WorldWideScience

Sample records for wind measurement sensors

  1. How good are remote sensors at measuring extreme winds?

    NARCIS (Netherlands)

    Sathe, A.R.; Courtney, M.; Mann, J.; Wagner, R.

    2011-01-01

    This article describes some preliminary efforts within the SafeWind project, aimed to identify the possible added value of using wind lidars to detect extreme wind events. Exceptionally good performance is now regularly reported in the measurement of the mean wind speed with some wind lidars in flat

  2. Measurements of Coastal Winds and Temperature. Sensor Evaluation, Data Quality, and Wind Structures

    Energy Technology Data Exchange (ETDEWEB)

    Heggem, Tore

    1997-12-31

    The long Norwegian coastline has excellent sites for wind power production. This thesis contains a documentation of a measurement station for maritime meteorological data at the coast of Mid-Norway, and analysis of temperature and wind data. It discusses experience with different types of wind speed and wind direction sensors. Accurate air temperature measurements are essential to obtain information about the stability of the atmosphere, and a sensor based on separately calibrated thermistors is described. The quality of the calibrations and the measurements is discussed. A database built up from measurements from 1982 to 1995 has been available. The data acquisition systems and the programs used to read the data are described, as well as data control and gap-filling methods. Then basic statistics from the data like mean values and distributions are given. Quality control of the measurements with emphasis on shade effects from the masts and direction alignment is discussed. The concept of atmospheric stability is discussed. The temperature profile tends to change from unstable to slightly stable as maritime winds passes land. Temperature spectra based on two-year time series are presented. Finally, there is a discussion of long-term turbulence spectra calculated from 14 years of measurements. The lack of a gap in the one-hour region of the spectra is explained from the overweight of unstable atmospheric conditions in the dominating maritime wind. Examples of time series with regular 40-minute cycles, and corresponding effect spectra are given. The validity of local lapse rate as a criterion of atmospheric stability is discussed. 34 refs., 86 figs., 11 tabs.

  3. Measurements of Coastal Winds and Temperature. Sensor Evaluation, Data Quality, and Wind Structures

    Energy Technology Data Exchange (ETDEWEB)

    Heggem, Tore

    1998-12-31

    The long Norwegian coastline has excellent sites for wind power production. This thesis contains a documentation of a measurement station for maritime meteorological data at the coast of Mid-Norway, and analysis of temperature and wind data. It discusses experience with different types of wind speed and wind direction sensors. Accurate air temperature measurements are essential to obtain information about the stability of the atmosphere, and a sensor based on separately calibrated thermistors is described. The quality of the calibrations and the measurements is discussed. A database built up from measurements from 1982 to 1995 has been available. The data acquisition systems and the programs used to read the data are described, as well as data control and gap-filling methods. Then basic statistics from the data like mean values and distributions are given. Quality control of the measurements with emphasis on shade effects from the masts and direction alignment is discussed. The concept of atmospheric stability is discussed. The temperature profile tends to change from unstable to slightly stable as maritime winds passes land. Temperature spectra based on two-year time series are presented. Finally, there is a discussion of long-term turbulence spectra calculated from 14 years of measurements. The lack of a gap in the one-hour region of the spectra is explained from the overweight of unstable atmospheric conditions in the dominating maritime wind. Examples of time series with regular 40-minute cycles, and corresponding effect spectra are given. The validity of local lapse rate as a criterion of atmospheric stability is discussed. 34 refs., 86 figs., 11 tabs.

  4. Measurement of temperature and pressure on the surface of a blunt cone using FBG sensor in hypersonic wind tunnel

    Science.gov (United States)

    Prasad, A. S. Guru; Sharath, U.; Nagarjun, V.; Hegde, G. M.; Asokan, S.

    2013-09-01

    Measurement of temperature and pressure exerted on the leeward surface of a blunt cone specimen has been demonstrated in the present work in a hypersonic wind tunnel using fiber Bragg grating (FBG) sensors. The experiments were conducted on a 30° apex-angle blunt cone with 51 mm base diameter at wind flow speeds of Mach 6.5 and 8.35 in a 300 mm hypersonic wind tunnel of Indian Institute of Science, Bangalore. A special pressure insensitive temperature sensor probe along with the conventional bare FBG sensors was used for explicit temperature and aerodynamic pressure measurement respectively on the leeward surface of the specimen. computational fluid dynamics (CFD) simulation of the flow field around the blunt cone specimen has also been carried out to obtain the temperature and pressure at conditions analogous to experiments. The results obtained from FBG sensors and the CFD simulations are found to be in good agreement with each other.

  5. Measurement of temperature and pressure on the surface of a blunt cone using FBG sensor in hypersonic wind tunnel

    International Nuclear Information System (INIS)

    Guru Prasad, A S; Sharath, U; Asokan, S; Nagarjun, V; Hegde, G M

    2013-01-01

    Measurement of temperature and pressure exerted on the leeward surface of a blunt cone specimen has been demonstrated in the present work in a hypersonic wind tunnel using fiber Bragg grating (FBG) sensors. The experiments were conducted on a 30° apex-angle blunt cone with 51 mm base diameter at wind flow speeds of Mach 6.5 and 8.35 in a 300 mm hypersonic wind tunnel of Indian Institute of Science, Bangalore. A special pressure insensitive temperature sensor probe along with the conventional bare FBG sensors was used for explicit temperature and aerodynamic pressure measurement respectively on the leeward surface of the specimen. computational fluid dynamics (CFD) simulation of the flow field around the blunt cone specimen has also been carried out to obtain the temperature and pressure at conditions analogous to experiments. The results obtained from FBG sensors and the CFD simulations are found to be in good agreement with each other. (paper)

  6. A comparison of Doppler lidar wind sensors for Earth-orbit global measurement applications

    Science.gov (United States)

    Menzies, Robert T.

    1985-01-01

    Now, there are four Doppler lidar configurations which are being promoted for the measurement of tropospheric winds: (1) the coherent CO2 Lidar, operating in the 9 micrometer region using a pulsed, atmospheric pressure CO2 gas discharge laser transmitter, and heterodyne detection; (2) the coherent Neodymium doped YAG or Glass Lidar, operating at 1.06 micrometers, using flashlamp or diode laser optical pumping of the solid state laser medium, and heterodyne detection; (3) the Neodymium doped YAG/Glass Lidar, operating at the doubled frequency (at 530 nm wavelength), again using flashlamp or diode laser pumping of the laser transmitter, and using a high resolution tandem Fabry-Perot filter and direct detection; and (4) the Raman shifted Xenon Chloride Lidar, operating at 350 nm wavelength, using a pulsed, atmospheric pressure XeCl gas discharge laser transmitter at 308 nm, Raman shifted in a high pressure hydrogen cell to 350 nm in order to avoid strong stratospheric ozone absorption, also using a high resolution tandem Fabry-Perot filter and direct detection. Comparisons of these four systems can include many factors and tradeoffs. The major portion of this comparison is devoted to efficiency. Efficiency comparisons are made by estimating the number of transmitted photons required for a single pulse wind velocity estimate of + or - 1 m/s accuracy in the middle troposphere, from an altitude of 800 km, which is assured to be reasonable for a polar orbiting platform.

  7. Optimisation of Data Acquisition in Wind Turbines with Data-Driven Conversion Functions for Sensor Measurements

    DEFF Research Database (Denmark)

    Colone, Lorenzo; Reder, M.; Tautz-Weinert, J.

    2017-01-01

    and evaluate their performance. A subsequent sensitivity analysis measuring the impact of the input variables on the predicted response reveals hidden relationships between signals. The concept feasibility is tested in a case study using Supervisory Control And Data Acquisition (SCADA) data from an offshore...

  8. A Long-Period Grating Sensor for Wind Turbine Blades

    DEFF Research Database (Denmark)

    Glavind, Lars

    This PhD project concerns the applied research for providing a novel sensor for measurements on wind turbine blades, based on Long-Period Gratings. The idea is based on the utilization of a special asymmetrical optical fibre with Long-Period Gratings for directional sensitive bend sensing...... blade material, where a suitable process and recoating material were investigated. The sensor was implemented and tested on a full scale wind turbine blade placed on a test rig. This first prototype has demonstrated the capability of the sensor for wind turbine blade monitoring, particular...... the possibility to distinguish between the flap- and edge-wise bend directions on the wind turbine blade, providing a selective sensor. The sensor has proven to be very robust and suitable for this application....

  9. VisibleWind: wind profile measurements at low altitude

    Science.gov (United States)

    Wilkerson, Tom; Bradford, Bill; Marchant, Alan; Apedaile, Tom; Wright, Cordell

    2009-09-01

    VisibleWindTM is developing an inexpensive rapid response system, for accurately characterizing wind shear and small scale wind phenomena in the boundary layer and for prospecting suitable locations for wind power turbines. The ValidWind system can also collect reliable "ground truth" for other remote wind sensors. The system employs small (0.25 m dia.) lightweight balloons and a tracker consisting of an Impulse 200 XL laser rangefinder coupled to a PC for automated data recording. Experiments on balloon trajectories demonstrate that the laser detection of range (+/- 0.5 m), together with measured azimuth and altitude, is an inexpensive, convenient, and capable alternative to other wind tracking methods. The maximum detection range has been increased to 2200 meters using micro-corner-cube retroreflector tape on balloons. Low power LEDs enable nighttime tracking. To avoid large balloon gyrations about the mean trajectory, we use balloons having low ascent rates and subcritical Reynolds numbers. Trajectory points are typically recorded every 4 - 7 seconds. Atmospheric features observed under conditions of inversions or "light and variable winds" include abrupt onsets of shear at altitudes of 100-250 m, velocity changes of order 1-3 m/s within layers of 10-20 m thickness, and veering of the wind direction by 180 degrees or more as altitude increases from 300 to 500 m. We have previously reported comparisons of balloon-based wind profiles with the output of a co-located sodar. Even with the Impulse rangefinder, our system still requires a "man in the loop" to track the balloon. A future system enhancement will automate balloon tracking, so that laser returns are obtained automatically at 1 Hz. While balloon measurements of large-scale, high altitude wind profiles are well known, this novel measurement system provides high-resolution, real-time characterization of the fluctuating local wind fields at the bottom of the boundary layer where wind power turbines and other

  10. A Wind Energy Powered Wireless Temperature Sensor Node

    Directory of Open Access Journals (Sweden)

    Chuang Zhang

    2015-02-01

    Full Text Available A wireless temperature sensor node composed of a piezoelectric wind energy harvester, a temperature sensor, a microcontroller, a power management circuit and a wireless transmitting module was developed. The wind-induced vibration energy harvester with a cuboid chamber of 62 mm × 19.6 mm × 10 mm converts ambient wind energy into electrical energy to power the sensor node. A TMP102 temperature sensor and the MSP430 microcontroller are used to measure the temperature. The power management module consists of LTC3588-1 and LT3009 units. The measured temperature is transmitted by the nRF24l01 transceiver. Experimental results show that the critical wind speed of the harvester was about 5.4 m/s and the output power of the harvester was about 1.59 mW for the electrical load of 20 kΩ at wind speed of 11.2 m/s, which was sufficient to power the wireless sensor node to measure and transmit the temperature every 13 s. When the wind speed increased from 6 m/s to 11.5 m/s, the self-powered wireless sensor node worked normally.

  11. Wind Speed Measurement by Paper Anemometer

    Science.gov (United States)

    Zhong, Juhua; Cheng, Zhongqi; Guan, Wenchuan

    2011-01-01

    A simple wind speed measurement device, a paper anemometer, is fabricated based on the theory of standing waves. In providing the working profile of the paper anemometer, an experimental device is established, which consists of an anemometer sensor, a sound sensor, a microphone, paper strips, a paper cup, and sonic acquisition software. It shows…

  12. Using wind speed from a blade-mounted flow sensor for power and load assessment on modern wind turbines

    DEFF Research Database (Denmark)

    Pedersen, Mads M.; Larsen, Torben J.; Madsen, Helge Aa

    2017-01-01

    In this paper an alternative method to evaluate power performance and loads on wind turbines using a blade-mounted flow sensor is investigated. The hypothesis is that the wind speed measured at the blades has a high correlation with the power and loads such that a power or load assessment can...... be performed from a few hours or days of measurements. In the present study a blade-mounted five-hole pitot tube is used as the flow sensor as an alternative to the conventional approach, where the reference wind speed is either measured at a nearby met mast or on the nacelle using lidar technology or cup...... anemometers. From the flow sensor measurements, an accurate estimate of the wind speed at the rotor plane can be obtained. This wind speed is disturbed by the presence of the wind turbine, and it is therefore different from the free-flow wind speed. However, the recorded wind speed has a high correlation...

  13. Wind Tunnel Measurements at LM Wind Power

    DEFF Research Database (Denmark)

    Bertagnolio, Franck

    2012-01-01

    This section presents the results obtained during the experimental campaign that was conducted in the wind tunnel at LM Wind Power in Lunderskov from August 16th to 26th, 2010. The goal of this study is to validate the so-called TNO trailing edge noise model through measurements of the boundary...... layer turbulence characteristics and the far-field noise generated by the acoustic scattering of the turbulent boundary layer vorticies as they convect past the trailing edge. This campaign was conducted with a NACA0015 airfoil section that was placed in the wind tunnel section. It is equipped with high...

  14. Autonomous Aerial Sensors for Wind Power Meteorology

    DEFF Research Database (Denmark)

    Giebel, Gregor; Schmidt Paulsen, Uwe; Reuder, Joachim

    2011-01-01

    , UAVs could be quite cost-effective. In order to test this assumption and to test the limits of UAVs for wind power meteorology, this project assembles four different UAVs from four participating groups. Risø has built a lighter-than-air kite with a long tether, Bergen University flies a derivative......This paper describes a new approach for measurements in wind power meteorology using small unmanned flying platforms. Large-scale wind farms, especially offshore, need an optimisation between installed wind power density and the losses in the wind farm due to wake effects between the turbines. Good...... movement. In any case, a good LIDAR or SODAR will cost many tenthousands of euros. Another current problem in wind energy is the coming generation of wind turbines in the 10-12MW class, with tip heights of over 200m. Very few measurement masts exist to verify our knowledge of atmospheric physics, and most...

  15. Optimal sensor placement for modal testing on wind turbines

    Science.gov (United States)

    Schulze, Andreas; Zierath, János; Rosenow, Sven-Erik; Bockhahn, Reik; Rachholz, Roman; Woernle, Christoph

    2016-09-01

    The mechanical design of wind turbines requires a profound understanding of the dynamic behaviour. Even though highly detailed simulation models are already in use to support wind turbine design, modal testing on a real prototype is irreplaceable to identify site-specific conditions such as the stiffness of the tower foundation. Correct identification of the mode shapes of a complex mechanical structure much depends on the placement of the sensors. For operational modal analysis of a 3 MW wind turbine with a 120 m rotor on a 100 m tower developed by W2E Wind to Energy, algorithms for optimal placement of acceleration sensors are applied. The mode shapes used for the optimisation are calculated by means of a detailed flexible multibody model of the wind turbine. Among the three algorithms in this study, the genetic algorithm with weighted off-diagonal criterion yields the sensor configuration with the highest quality. The ongoing measurements on the prototype will be the basis for the development of optimised wind turbine designs.

  16. Pressure Measurement Sensor

    Science.gov (United States)

    1997-01-01

    FFPI Industries Inc. is the manufacturer of fiber-optic sensors that furnish accurate pressure measurements in internal combustion chambers. Such an assessment can help reduce pollution emitted by these engines. A chief component in the sensor owes its seven year- long development to Lewis Research Center funding to embed optical fibers and sensors in metal parts. NASA support to Texas A&M University played a critical role in developing this fiber optic technology and led to the formation of FFPI Industries and the production of fiber sensor products. The simple, rugged design of the sensor offers the potential for mass production at low cost. Widespread application of the new technology is forseen, from natural gas transmission, oil refining and electrical power generation to rail transport and the petrochemical paper product industry.

  17. Can Wind Lidars Measure Turbulence?

    DEFF Research Database (Denmark)

    Sathe, Ameya; Mann, Jakob; Gottschall, Julia

    2011-01-01

    Modeling of the systematic errors in the second-order moments of wind speeds measured by continuous-wave (ZephIR) and pulsed (WindCube) lidars is presented. These lidars use the conical scanning technique to measure the velocity field. The model captures the effect of volume illumination and coni...

  18. Self-Powered Wind Sensor System for Detecting Wind Speed and Direction Based on a Triboelectric Nanogenerator.

    Science.gov (United States)

    Wang, Jiyu; Ding, Wenbo; Pan, Lun; Wu, Changsheng; Yu, Hua; Yang, Lijun; Liao, Ruijin; Wang, Zhong Lin

    2018-04-24

    The development of the Internet of Things has brought new challenges to the corresponding distributed sensor systems. Self-powered sensors that can perceive and respond to environmental stimuli without an external power supply are highly desirable. In this paper, a self-powered wind sensor system based on an anemometer triboelectric nanogenerator (a-TENG, free-standing mode) and a wind vane triboelectric nanogenerator (v-TENG, single-electrode mode) is proposed for simultaneously detecting wind speed and direction. A soft friction mode is adopted instead of a typical rigid friction for largely enhancing the output performance of the TENG. The design parameters including size, unit central angle, and applied materials are optimized to enhance sensitivity, resolution, and wide measurement scale. The optimized a-TENG could deliver an open-circuit voltage of 88 V and short-circuit current of 6.3 μA, corresponding to a maximum power output of 0.47 mW (wind speed of 6.0 m/s), which is capable of driving electronics for data transmission and storage. The current peak value of the a-TENG signal is used for analyzing wind speed for less energy consumption. Moreover, the output characteristics of a v-TENG are further explored, with six actual operation situations, and the v-TENG delivers fast response to the incoming wind and accurately outputs the wind direction data. As a wind sensor system, wind speed ranging from 2.7 to 8.0 m/s can be well detected (consistent with a commercial sensor) and eight regular directions can be monitored. Therefore, the fabricated wind sensor system has great potential in wireless environmental monitoring applications.

  19. Autonomous Aerial Sensors for Wind Power Meteorology

    DEFF Research Database (Denmark)

    Giebel, Gregor; la Cour-Harbo, Anders; Bange, Jens

    2012-01-01

    built a lighter-than-air kite with a long tether and nano-synchronised sensors, Bergen University flies the SUMO, a pusher airplane of 580g total weight equipped with a 100Hz Pitot tube, Tübingen University in conjunction with the TU Braunschweig flies the Carolo, a 2m wide two prop model with a 5-hole...... concern - both the campaign at Høvsøre and the alternate location at Risø had to be cancelled for different reasons, both related to flying permits. There was one week of flying though at the Nøjsomheds Odde wind farm in Lolland, where we could compare the SUMO and balloon with a Lidar and data from...

  20. Representivity of wind measurements for design wind speed estimations

    CSIR Research Space (South Africa)

    Goliger, Adam M

    2013-07-01

    Full Text Available of instrumentation sited according to World Meteorological Organization (WMO) requirements. With the advent of automatic weather station technology several decades ago, wind measurements have become much more cost-effective. While previously wind measurements were...

  1. Online wind turbine measurement laboratory

    DEFF Research Database (Denmark)

    Hansen, K.S.; Helgesen Pedersen, K.O.; Schmidt Paulsen, U.

    2006-01-01

    conditions, 3) electrical quantities and 4) mechanical loads in terms of strain gauge signals. The data acquisition system has been designed and implemented by Risø together with students and teachers from DTU. It is based on LabVIEW© combined with a MySQL database for data management. The system enables...... calculations and extreme loads estimation in basic wind turbine courses. Power quality analysis is carried out based on high speed sampled, three-phase voltage and current signals. The wide spectrum of sensors enables a detailed study of the correlation between meteorological, mechanical and electrical...

  2. Sensor comparison study for load alleviating wind turbine pitch control

    DEFF Research Database (Denmark)

    Kragh, Knud Abildgaard; Hansen, Morten Hartvig; Henriksen, Lars Christian

    2014-01-01

    As the size of wind turbines increases, the load alleviating capabilities of the turbine controller are becoming increasingly important. Load alleviating control schemes have traditionally been based on feedback from load sensor; however, recent developments of measurement technologies have enabled...... control on the basis of preview measurements of the inflow acquired using, e.g., light detection and ranging. The potential of alleviating load variations that are caused by mean wind speed changes through feed-forward control have been demonstrated through both experiments and simulations in several...... studies, whereas the potential of preview control for alleviating the load variations caused by azimuth dependent inflow variations is less described. Individual or cyclic pitch is required to alleviate azimuth dependent load variations and is traditionally applied through feedback control of the blade...

  3. LIDAR Wind Speed Measurements of Evolving Wind Fields

    Energy Technology Data Exchange (ETDEWEB)

    Simley, E.; Pao, L. Y.

    2012-07-01

    Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feedforward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. Past studies have assumed Taylor's frozen turbulence hypothesis, which implies that turbulence remains unchanged as it advects downwind at the mean wind speed. With Taylor's hypothesis applied, the only source of wind speed measurement error is distortion caused by the LIDAR. This study introduces wind evolution, characterized by the longitudinal coherence of the wind, to LIDAR measurement simulations to create a more realistic measurement model. A simple model of wind evolution is applied to a frozen wind field used in previous studies to investigate the effects of varying the intensity of wind evolution. LIDAR measurements are also evaluated with a large eddy simulation of a stable boundary layer provided by the National Center for Atmospheric Research. Simulation results show the combined effects of LIDAR errors and wind evolution for realistic turbine-mounted LIDAR measurement scenarios.

  4. Measuring Gas Concentration and Wind Intensity in a Turbulent Wind Tunnel with a Mobile Robot

    Directory of Open Access Journals (Sweden)

    Dani Martínez

    2016-01-01

    Full Text Available This paper presents the measurement of gas concentration and wind intensity performed with a mobile robot in a custom turbulent wind tunnel designed for experimentation with customizable wind and gas leak sources. This paper presents the representation in different information layers of the measurements obtained in the turbulent wind tunnel under different controlled environmental conditions in order to describe the plume of the gas and wind intensities inside the experimentation chamber. The information layers have been generated from the measurements gathered by individual onboard gas and wind sensors carried out by an autonomous mobile robot. On the one hand, the assumption was that the size and cost of these specialized sensors do not allow the creation of a net of sensors or other measurement alternatives based on the simultaneous use of several sensors, and on the other hand, the assumption is that the information layers created will have application on the development and test of automatic gas source location procedures based on reactive or nonreactive algorithms.

  5. Using wind speed from a blade-mounted flow sensor for power and load assessment on modern wind turbines

    Directory of Open Access Journals (Sweden)

    M. M. Pedersen

    2017-11-01

    Full Text Available In this paper an alternative method to evaluate power performance and loads on wind turbines using a blade-mounted flow sensor is investigated. The hypothesis is that the wind speed measured at the blades has a high correlation with the power and loads such that a power or load assessment can be performed from a few hours or days of measurements.In the present study a blade-mounted five-hole pitot tube is used as the flow sensor as an alternative to the conventional approach, where the reference wind speed is either measured at a nearby met mast or on the nacelle using lidar technology or cup anemometers. From the flow sensor measurements, an accurate estimate of the wind speed at the rotor plane can be obtained. This wind speed is disturbed by the presence of the wind turbine, and it is therefore different from the free-flow wind speed. However, the recorded wind speed has a high correlation with the actual power production as well as the flap-wise loads as it is measured close to the blade where the aerodynamic forces are acting.Conventional power curves are based on at least 180 h of 10 min mean values, but using the blade-mounted flow sensor both the observation average time and the overall assessment time can potentially be shortened. The basis for this hypothesis is that the sensor is able to provide more observations with higher accuracy, as the sensor follows the rotation of the rotor and because of the high correlation between the flow at the blades and the power production. This is the research question addressed in this paper.The method is first tested using aeroelastic simulations where the dependence of the radial position and effect of multiple blade-mounted flow sensors are also investigated. Next the method is evaluated on the basis of full-scale measurements on a pitch-regulated, variable-speed 3.6 MW wind turbine.It is concluded that the wind speed derived from the blade-mounted flow sensor is highly correlated with the

  6. RSA/Legacy Wind Sensor Comparison. Part 2; Eastern Range

    Science.gov (United States)

    Short, David A.; Wheeler, Mark M.

    2006-01-01

    This report describes a comparison of data from ultrasonic and propeller-and-vane anemometers on 5 wind towers at Kennedy Space Center and Cape Canaveral Air Force Station. The ultrasonic sensors are scheduled to replace the Legacy propeller-and-vane sensors under the Range Standardization and Automation (RSA) program. Because previous studies have noted differences between peak wind speeds reported by mechanical and ultrasonic wind sensors, the latter having no moving parts, the 30th and 45th Weather Squadrons wanted to understand possible differences between the two sensor types. The period-of-record was 13-30 May 2005, A total of 357,626 readings of 1-minute average and peak wind speed/direction from each sensor type were used. Statistics of differences in speed and direction were used to identify 15 out of 19 RSA sensors having the most consistent performance, with respect to the Legacy sensors. RSA average wind speed data from these 15 showed a small positive bias of 0.38 kts. A slightly larger positive bias of 0.94 kts was found in the RSA peak wind speed.

  7. RSA/Legacy Wind Sensor Comparison. Part 1; Western Range

    Science.gov (United States)

    Short, David A.; Wheeler, Mark M.

    2006-01-01

    This report describes a comparison of data from ultrasonic and cup-and-vane anemometers on 5 wind towers at Vandenberg AFB. The ultrasonic sensors are scheduled to replace the Legacy cup-and-vane sensors under the Range Standardization and Automation (RSA) program. Because previous studies have noted differences between peak wind speeds reported by mechanical and ultrasonic wind sensors, the latter having no moving parts, the 30th and 45th Weather Squadrons wanted to understand possible differences between the two sensor types. The period-of-record was 13-30 May 2005. A total of 153,961 readings of I-minute average and peak wind speed/direction from each sensor type were used. Statistics of differences in speed and direction were used to identify 18 out of 34 RSA sensors having the most consistent performance, with respect to the Legacy sensors. Data from these 18 were used to form a composite comparison. A small positive bias in the composite RSA average wind speed increased from +0.5 kts at 15 kts, to +1 kt at 25 kts. A slightly larger positive bias in the RSA peak wind speed increased from +1 kt at 15 kts, to +2 kts at 30 kts.

  8. Simultaneous Fault Detection and Sensor Selection for Condition Monitoring of Wind Turbines

    Directory of Open Access Journals (Sweden)

    Wenna Zhang

    2016-04-01

    Full Text Available Data collected from the supervisory control and data acquisition (SCADA system are used widely in wind farms to obtain operation and performance information about wind turbines. The paper presents a three-way model by means of parallel factor analysis (PARAFAC for wind turbine fault detection and sensor selection, and evaluates the method with SCADA data obtained from an operational farm. The main characteristic of this new approach is that it can be used to simultaneously explore measurement sample profiles and sensors profiles to avoid discarding potentially relevant information for feature extraction. With K-means clustering method, the measurement data indicating normal, fault and alarm conditions of the wind turbines can be identified, and the sensor array can be optimised for effective condition monitoring.

  9. Wind Speed Preview Measurement and Estimation for Feedforward Control of Wind Turbines

    Science.gov (United States)

    Simley, Eric J.

    the turbine are unknown, a Kalman filter-based wind speed estimator is developed that relies on turbine sensor outputs. Using simulated lidar measurements in conjunction with wind speed estimator outputs based on aeroelastic simulations of the NREL 5-MW turbine model, it is shown how the optimal prefilter can adapt to varying degrees of measurement quality.

  10. Measurement, instrumentation, and sensors handbook

    CERN Document Server

    Eren, Halit

    2014-01-01

    The Second Edition of the bestselling Measurement, Instrumentation, and Sensors Handbook brings together all aspects of the design and implementation of measurement, instrumentation, and sensors. Reflecting the current state of the art, it describes the use of instruments and techniques for performing practical measurements in engineering, physics, chemistry, and the life sciences and discusses processing systems, automatic data acquisition, reduction and analysis, operation characteristics, accuracy, errors, calibrations, and the incorporation of standards for control purposes. Organized acco

  11. Wind Velocity and Position Sensor-less Operation for PMSG Wind Generator

    Science.gov (United States)

    Senjyu, Tomonobu; Tamaki, Satoshi; Urasaki, Naomitsu; Uezato, Katsumi; Funabashi, Toshihisa; Fujita, Hideki

    Electric power generation using non-conventional sources is receiving considerable attention throughout the world. Wind energy is one of the available non-conventional energy sources. Electrical power generation using wind energy is possible in two ways, viz. constant speed operation and variable speed operation using power electronic converters. Variable speed power generation is attractive, because maximum electric power can be generated at all wind velocities. However, this system requires a rotor speed sensor, for vector control purpose, which increases the cost of the system. To alleviate the need of rotor speed sensor in vector control, we propose a new sensor-less control of PMSG (Permanent Magnet Synchronous Generator) based on the flux linkage. We can estimate the rotor position using the estimated flux linkage. We use a first-order lag compensator to obtain the flux linkage. Furthermore‚we estimate wind velocity and rotation speed using a observer. The effectiveness of the proposed method is demonstrated thorough simulation results.

  12. High resolution climatological wind measurements for wind energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, H. [Uppsala Univ. (Sweden). Dept. of Meteorology

    1996-12-01

    Measurements with a combined cup anemometer/wind vane instrument, developed at the Department of Meteorology in Uppsala, is presented. The instrument has a frequency response of about 1 Hz, making it suitable not only for mean wind measurements, but also for studies of atmospheric turbulence. It is robust enough to be used for climatological purposes. Comparisons with data from a hot-film anemometer show good agreement, both as regards standard deviations and the spectral decomposition of the turbulent wind signal. The cup anemometer/wind vane instrument is currently used at three sites within the Swedish wind energy research programme. These measurements are shortly described, and a few examples of the results are given. 1 ref, 10 figs

  13. Validation of Sodar Measurements for Wind Power

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose

    2006-01-01

    the project and a new remote power system has been designed. A direct comparison between SODAR and cup measurements revealed a limitation for the SODAR measurements during different weather conditions, especially since the SODAR was not able to measure wind speeds above 15 m/s due to an increasing back-ground......A ground-based SODAR has been tested for 1½ years together with a traditional measurement set-up consisting of cups and vanes for measuring wind data for wind power assessment at a remote location. Many problems associated to the operation of a remote located SODAR have been solved during...... noise. Instead, using the SODAR as a profiler to establish representative wind speed profiles was successful. These wind speed profiles are combined with low height reference measurements to establish reliable hub height wind speed distributions. Representative wind speed profiles can be establish...

  14. Fiber optic pressure sensors in skin-friction measurements

    Science.gov (United States)

    Kidwell, R.

    1985-01-01

    Fiber optic lever pressure sensors intended for use in a low speed wind tunnel environment were designed, constructed and tested for the measurement of normal and shear displacements associated with the pressures acting on a flat aluminum plate. On-site tests performed along with several static and dynamic measurements made have established that, with proper modifications and improvements, the design concepts are acceptable and can be utilized for their intended use. Several elastomers were investigated for use in sensors and for their incorporation into these sensors. Design and assembly techniques for probes and complete sensors were developed.

  15. Novel Sensor for Wind Tunnel Calibration and Characterization, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Advances in computational capabilities for modeling the performance of advanced flight vehicles depend on verification measurements made in ground-based wind...

  16. Data-Driven Method for Wind Turbine Yaw Angle Sensor Zero-Point Shifting Fault Detection

    Directory of Open Access Journals (Sweden)

    Yan Pei

    2018-03-01

    Full Text Available Wind turbine yaw control plays an important role in increasing the wind turbine production and also in protecting the wind turbine. Accurate measurement of yaw angle is the basis of an effective wind turbine yaw controller. The accuracy of yaw angle measurement is affected significantly by the problem of zero-point shifting. Hence, it is essential to evaluate the zero-point shifting error on wind turbines on-line in order to improve the reliability of yaw angle measurement in real time. Particularly, qualitative evaluation of the zero-point shifting error could be useful for wind farm operators to realize prompt and cost-effective maintenance on yaw angle sensors. In the aim of qualitatively evaluating the zero-point shifting error, the yaw angle sensor zero-point shifting fault is firstly defined in this paper. A data-driven method is then proposed to detect the zero-point shifting fault based on Supervisory Control and Data Acquisition (SCADA data. The zero-point shifting fault is detected in the proposed method by analyzing the power performance under different yaw angles. The SCADA data are partitioned into different bins according to both wind speed and yaw angle in order to deeply evaluate the power performance. An indicator is proposed in this method for power performance evaluation under each yaw angle. The yaw angle with the largest indicator is considered as the yaw angle measurement error in our work. A zero-point shifting fault would trigger an alarm if the error is larger than a predefined threshold. Case studies from several actual wind farms proved the effectiveness of the proposed method in detecting zero-point shifting fault and also in improving the wind turbine performance. Results of the proposed method could be useful for wind farm operators to realize prompt adjustment if there exists a large error of yaw angle measurement.

  17. Observer Based Detection of Sensor Faults in Wind Turbines

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Nielsen, R.

    2009-01-01

    , if an unknown input observer the fault detection  scheme can be non dependent on the actual wind speed. The scheme  is validated on data from a more advanced and detailed simulation  model. The proposed scheme detects the sensor faults a few samples  after the beginning of the faults....

  18. A simulation environment for assisting system design of coherent laser doppler wind sensor for active wind turbine pitch control

    Science.gov (United States)

    Shinohara, Leilei; Pham Tran, Tuan Anh; Beuth, Thorsten; Umesh Babu, Harsha; Heussner, Nico; Bogatscher, Siegwart; Danilova, Svetlana; Stork, Wilhelm

    2013-05-01

    In order to assist a system design of laser coherent Doppler wind sensor for active pitch control of wind turbine systems (WTS), we developed a numerical simulation environment for modeling and simulation of the sensor system. In this paper we present this simulation concept. In previous works, we have shown the general idea and the possibility of using a low cost coherent laser Doppler wind sensing system for an active pitch control of WTS in order to achieve a reduced mechanical stress, increase the WTS lifetime and therefore reduce the electricity price from wind energy. Such a system is based on a 1.55μm Continuous-Wave (CW) laser plus an erbium-doped fiber amplifier (EDFA) with an output power of 1W. Within this system, an optical coherent detection method is chosen for the Doppler frequency measurement in megahertz range. A comparatively low cost short coherent length laser with a fiber delay line is used for achieving a multiple range measurement. In this paper, we show the current results on the improvement of our simulation by applying a Monte Carlo random generation method for positioning the random particles in atmosphere and extend the simulation to the entire beam penetrated space by introducing a cylindrical co-ordinate concept and meshing the entire volume into small elements in order to achieve a faster calculation and gain more realistic simulation result. In addition, by applying different atmospheric parameters, such as particle sizes and distributions, we can simulate different weather and wind situations.

  19. High resolution wind measurements for offshore wind energy development

    Science.gov (United States)

    Nghiem, Son Van (Inventor); Neumann, Gregory (Inventor)

    2013-01-01

    A method, apparatus, system, article of manufacture, and computer readable storage medium provide the ability to measure wind. Data at a first resolution (i.e., low resolution data) is collected by a satellite scatterometer. Thin slices of the data are determined. A collocation of the data slices are determined at each grid cell center to obtain ensembles of collocated data slices. Each ensemble of collocated data slices is decomposed into a mean part and a fluctuating part. The data is reconstructed at a second resolution from the mean part and a residue of the fluctuating part. A wind measurement is determined from the data at the second resolution using a wind model function. A description of the wind measurement is output.

  20. Doppler Navigation System with a Non-Stabilized Antenna as a Sea-Surface Wind Sensor.

    Science.gov (United States)

    Nekrasov, Alexey; Khachaturian, Alena; Veremyev, Vladimir; Bogachev, Mikhail

    2017-06-09

    We propose a concept of the utilization of an aircraft Doppler Navigation System (DNS) as a sea-surface wind sensor complementary to its normal functionality. The DNS with an antenna, which is non-stabilized physically to the local horizontal with x -configured beams, is considered. We consider the wind measurements by the DNS configured in the multi-beam scatterometer mode for a rectilinear flight scenario. The system feasibility and the efficiency of the proposed wind algorithm retrieval are supported by computer simulations. Finally, the associated limitations of the proposed approach are considered.

  1. Simulation of the Impact of New Ocean Surface Wind Measurements on H*Wind Analyses

    Science.gov (United States)

    Miller, Timothy; Atlas, Robert; Black, Peter; Chen, Shuyi; Hood, Robbie; Johnson, James; Jones, Linwood; Ruf, Chris; Uhlhorn, Eric

    2008-01-01

    The H*Wind analysis, a product of the Hurricane Research Division of NOAA's Atlantic Oceanographic and Meteorological Laboratory, brings together wind measurements from a variety of observation platforms into an objective analysis of the distribution of surface wind speeds in a tropical cyclone. This product is designed to improve understanding of the extent and strength of the wind field, and to improve the assessment of hurricane intensity. See http://www.aoml.noaa.gov/hrd/data sub/wind.html. The Hurricane Imaging Radiometer (HIRAD) is a new passive microwave remote sensor for hurricane observations that is currently under development by NASA Marshall Space Flight Center, NOAA Hurricane Research Division, the University of Central Florida and the University of Michigan. HIRAD is being designed to enhance the current real-time airborne ocean surface winds observation capabilities of NOAA and USAF Weather Squadron hurricane hunter aircraft using the operational airbome Stepped Frequency Microwave Radiometer (SFMR). Unlike SFMR, which measures wind speed and rain rate along the ground track directly beneath the aircraft, HIRAD will provide images of the surface wind and rain field over a wide swath (approximately 3 x the aircraft altitude, or approximately 2 km from space). The instrument is described in a separate paper presented at this conference. The present paper describes a set of Observing System Simulation Experiments (OSSEs) in which measurements from the new instrument as well as those from existing instruments (air, surface, and space-based) are simulated from the output of a numerical model from the University of Miami, and those results are used to construct H*Wind analyses. Evaluations will be presented on the relative impact of HIRAD and other instruments on H*Wind analyses, including the use of HIRAD from 2 aircraft altitudes and from a space-based platform.

  2. Wind measurement via direct detection lidar

    Science.gov (United States)

    Afek, I.; Sela, N.; Narkiss, N.; Shamai, G.; Tsadka, S.

    2013-10-01

    Wind sensing Lidar is considered a promising technology for high quality wind measurements required for various applications such as hub height wind resource assessment, power curve measurements and advanced, real time, forward looking turbine control. Until recently, the only available Lidar technology was based on coherent Doppler shift detection, whose market acceptance has been slow primarily due to its exuberant price. Direct detection Lidar technology provides an alternative to remote sensing of wind by incorporating high precision measurement, a robust design and an affordable price tag.

  3. Optical sensors for mapping temperature and winds in the thermosphere from a CubeSat platform

    Science.gov (United States)

    Sullivan, Stephanie Whalen

    The thermosphere is the region between approximately 80 km and 320 or more km above the earth's surface. While many people consider this elevation to be space rather than atmosphere, there is a small quantity of gasses in this region. The behavior of these gasses influences the orbits of satellites, including the International Space Station, causes space weather events, and influences the weather closer to the surface of the earth. Due to the location and characteristics of the thermosphere, even basic properties such as temperature are very difficult to measure. High spatial and temporal resolution data on temperatures and winds in the thermosphere are needed by both the space weather and earth climate modeling communities. To address this need, Space Dynamics Laboratory (SDL) started the Profiling Oxygen Emissions of the Thermosphere (POET) program. POET consists of a series of sensors designed to fly on sounding rockets, CubeSats, or larger platforms, such as IridiumNEXT SensorPODS. While each sensor design is different, they all use characteristics of oxygen optical emissions to measure space weather properties. The POET program builds upon the work of the RAIDS, Odin, and UARS programs. Our intention is to dramatically reduce the costs of building, launching, and operating spectrometers in space, thus allowing for more sensors to be in operation. Continuous long-term data from multiple sensors is necessary to understand the underlying physics required to accurately model and predict weather in the thermosphere. While previous spectrometers have been built to measure winds and temperatures in the thermosphere, they have all been large and expensive. The POET sensors use new focal plane technology and optical designs to overcome these obstacles. This thesis focuses on the testing and calibration of the two POET sensors: the Oxygen Profiling of the Atmospheric Limb (OPAL) temperature sensor and the Split-field Etalon Doppler Imager (SEDI) wind sensor.

  4. Correlative studies of satellite ozone sensor measurements

    International Nuclear Information System (INIS)

    Lovill, J.E.; Ellis, J.S.

    1983-01-01

    Comparisons are made between total ozone measurements made by four satellite ozone sensors (TOMS, SBUV, TOVS and MFR). The comparisons were made during July 1979 when all sensors were operating simultaneously. The TOMS and SBUV sensors were observed to measure less total ozone than the MFR sensor, 10 and 15 Dobson units (DU) respectively. The MFR and TOMS sensors measured less ozone than the TOVS sensor, 19 an 28 DU, respectively. Latitudinal variability of the total ozone comparisons is discussed

  5. Range-Measuring Video Sensors

    Science.gov (United States)

    Howard, Richard T.; Briscoe, Jeri M.; Corder, Eric L.; Broderick, David

    2006-01-01

    Optoelectronic sensors of a proposed type would perform the functions of both electronic cameras and triangulation- type laser range finders. That is to say, these sensors would both (1) generate ordinary video or snapshot digital images and (2) measure the distances to selected spots in the images. These sensors would be well suited to use on robots that are required to measure distances to targets in their work spaces. In addition, these sensors could be used for all the purposes for which electronic cameras have been used heretofore. The simplest sensor of this type, illustrated schematically in the upper part of the figure, would include a laser, an electronic camera (either video or snapshot), a frame-grabber/image-capturing circuit, an image-data-storage memory circuit, and an image-data processor. There would be no moving parts. The laser would be positioned at a lateral distance d to one side of the camera and would be aimed parallel to the optical axis of the camera. When the range of a target in the field of view of the camera was required, the laser would be turned on and an image of the target would be stored and preprocessed to locate the angle (a) between the optical axis and the line of sight to the centroid of the laser spot.

  6. Mobile measurement system for wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Kildemoes Moeller, T.

    1997-06-01

    The aim of this project `Udviklingsafproevning af smaa moellevinger` has been to develop a mobile measurement system for wind turbines. The following report describes the measurement system. The project has been financed by the Danish Ministry of Energy. (au)

  7. Validation of Sodar Measurements for Wind Power

    OpenAIRE

    Hansen, Kurt Schaldemose

    2006-01-01

    A ground-based SODAR has been tested for 1½ years together with a traditional measurement set-up consisting of cups and vanes for measuring wind data for wind power assessment at a remote location. Many problems associated to the operation of a remote located SODAR have been solved during the project and a new remote power system has been designed. A direct comparison between SODAR and cup measurements revealed a limitation for the SODAR measurements during different weather conditions, espec...

  8. Atmospheric diffusion wind tunnel with automatic measurement

    Energy Technology Data Exchange (ETDEWEB)

    Maki, S; Sakai, J; Murata, E

    1974-01-01

    A wind tunnel which permits estimates of atmospheric diffusion is described. Smoke from power plant smoke stacks, for example, can be simulated and traced to determine the manner of diffusion in the air as well as the grade of dilution. The wind tunnel is also capable of temperature controlled diffusion tests in which temperature distribution inside the wind tunnel is controlled. A minimum wind velocity of 10 cm can be obtained with accuracy within plus or minus 0.05 percent using a controlled direct current motor; diffusion tests are often made at low wind velocity. Fully automatic measurements can be obtained by using a minicomputer so that the operation and reading of the measuring instruments can be remotely controlled from the measuring chamber. (Air Pollut. Abstr.)

  9. Wind turbine wake measurement in complex terrain

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Larsen, Gunner Chr.; Menke, Robert

    2016-01-01

    SCADA data from a wind farm and high frequency time series measurements obtained with remote scanning systems have been analysed with focus on identification of wind turbine wake properties in complex terrain. The analysis indicates that within the flow regime characterized by medium to large dow...

  10. Assessment of wind turbine load measurement instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Morfiadakis, E; Papadopoulos, K [CRES (Greece); Borg, N van der [ECN, Petten (Netherlands); Petersen, S M [Risoe, Roskilde (Denmark); Seifert, H [DEWI, Wilhelmshaven (Germany)

    1999-03-01

    In the framework of Sub-Task3 `Wind turbine load measurement instrumentation` of EU-project `European Wind Turbine Testing Procedure Development`, the load measurement techniques have been assessed by laboratory, full scale and numerical tests. The existing methods have been reviewed with emphasis on the strain gage application techniques on composite materials and recommendations are provided for the optimisation of load measurement techniques. (au) EU. 14 refs.

  11. Turbulent wind field characterization and re-generation based on pitot tube measurements mounted on a wind turbine

    DEFF Research Database (Denmark)

    Pedersen, Mads Mølgaard; Larsen, Torben J.; Aagaard Madsen, Helge

    2015-01-01

    models that compensate for axial and tangential induction, approximated by blade element momentum theory, radial expansion of the inflow, rotor tilt, dynamic and skew inflow, tip loss, as well as braking and circulation of the flow local to the airfoil. The wind speeds measured on the rotating blades...... the measured wind speeds at the recording position. In the theoretical part of this study a quite good agreement is seen between load sensors on a turbine model exposed to the reference and the re-generated turbulence field. Finally the method is applied to full scale measurements and reasonable wind shear...

  12. Measuring tropospheric wind with microwave sounders

    Science.gov (United States)

    Lambrigtsen, B.; Su, H.; Turk, J.; Hristova-Veleva, S. M.; Dang, V. T.

    2017-12-01

    In its 2007 "Decadal Survey" of earth science missions for NASA the U.S. National Research Council recommended that a Doppler wind lidar be developed for a three-dimensional tropospheric winds mission ("3D-Winds"). The technology required for such a mission has not yet been developed, and it is expected that the next Decadal Survey, planned to be released by the end of 2017, will put additional emphasis on the still pressing need for wind measurements from space. The first Decadal Survey also called for a geostationary microwave sounder (GMS) on a Precipitation and All-weather Temperature and Humidity (PATH) mission, which could be used to measure wind from space. Such a sounder, the Geostationary Synthetic Thinned Aperture Radiometer (GeoSTAR), has been developed at the Jet Propulsion Laboratory (JPL). The PATH mission has not yet been funded by NASA, but a low-cost subset of PATH, GeoStorm has been proposed as a hosted payload on a commercial communications satellite. Both PATH and GeoStorm would obtain frequent (every 15 minutes of better) measurements of tropospheric water vapor profiles, and they can be used to derive atmospheric motion vector (AMV) wind profiles, even in the presence of clouds. Measurement of wind is particularly important in the tropics, where the atmosphere is largely not in thermal balance and wind estimates cannot generally be derived from temperature and pressure fields. We report on simulation studies of AMV wind vectors derived from a GMS and from a cluster of low-earth-orbiting (LEO) small satellites (e.g., CubeSats). The results of two separate simulation studies are very encouraging and show that a ±2 m/s wind speed precision is attainable, which would satisfy WMO requirements. A GMS observing system in particular, which can be implemented now, would enable significant progress in the study of atmospheric dynamics. Copyright 2017 California Institute of Technology. Government sponsorship acknowledged

  13. Performance Enhancement and Load Reduction on Wind Turbines Using Inflow Measurements

    DEFF Research Database (Denmark)

    Kragh, Knud Abildgaard

    . The load variations on a wind turbine can be alleviated using either yaw or pitch actuation. A method is presented for alleviating load variations using yaw control, and it is shown how the method can be efficiently applied for decreasing the load variations that are caused by a vertical wind shear...... wind energy research is focused on decreasing the cost of the energy that can be produced from the wind. The cost of energy can for example be decreased by ensuring that wind turbines are operated in a way that ensures that the maximum amount of energy is extracted, and that the turbines are not loaded...... excessively. The operation of a wind turbine is governed by a number of controllers that are based on a series of sensors and actuators. Classical wind turbine control utilizes sensors for measuring turbine parameters such as rotor speed, power and shaft torque, as well as actuators for applying generator...

  14. The Skipheia Wind Measurement Station. Instrumentation, Wind Speed Profiles and Turbulence Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Aasen, S E

    1995-10-01

    This thesis describes the design of a measurement station for turbulent wind and presents results from an analysis of the collected data. The station is located at Skipheia near the south-west end of Froeya, an island off the coast of Mid-Norway. The station is unique for studies of turbulent winds because of the large numbers of sensors, which are located at various heights above ground up to 100 m, a sampling rate of 0.85 Hz and storage of the complete time series. The frequency of lightning and atmospheric discharges to the masts are quite high and much effort has gone into minimizing the damage caused by lightning activity. A major part of the thesis deals with data analysis and modelling. There are detailed discussions on the various types of wind sensors and their calibration, the data acquisition system and operating experiences with it, the database, data quality control, the wind speed profile and turbulence. 40 refs., 78 figs., 17 tabs.

  15. Structural Monitoring of Wind Turbines using Sensors Connected via UTP Cable

    Directory of Open Access Journals (Sweden)

    Dumitru SPERMEZAN

    2017-12-01

    Full Text Available Unpredicted faults that may occur at the wind generators elements affect their economic operation. A promising approach that avoids these faults is the real-time vibrations monitoring. Data measured by the sensors can be transmitted to a monitoring station using wireless techniques, or optical fiber, or UTP cable. The last possibility is the cheapest, but it permits connecting the monitoring station at a limited distance with respect to the monitored turbine. The paper presents the components of the monitoring system and the experimental results related to the monitored wind turbine.

  16. Ceramic thermal wind sensor based on advanced direct chip attaching package

    International Nuclear Information System (INIS)

    Zhou Lin; Qin Ming; Chen Shengqi; Chen Bei

    2014-01-01

    An advanced direct chip attaching packaged two-dimensional ceramic thermal wind sensor is studied. The thermal wind sensor chip is fabricated by metal lift-off processes on the ceramic substrate. An advanced direct chip attaching (DCA) packaging is adopted and this new packaged method simplifies the processes of packaging further. Simulations of the advanced DCA packaged sensor based on computational fluid dynamics (CFD) model show the sensor can detect wind speed and direction effectively. The wind tunnel testing results show the advanced DCA packaged sensor can detect the wind direction from 0° to 360° and wind speed from 0 to 20 m/s with the error less than 0.5 m/s. The nonlinear fitting based least square method in Matlab is used to analyze the performance of the sensor. (semiconductor devices)

  17. Calibration of an experimental six component wind tunnel block balance using optical fibre sensors

    CSIR Research Space (South Africa)

    de Ponte, JD

    2016-05-01

    Full Text Available In order to meet the increasingly stringent requirements for wind tunnel balances, as expressed by the wind tunnel testing community, balance design philosophy needs to be further expanded to include alternative sensor, material, design...

  18. Design and development of an experimental six component wind tunnel block balance using optical fibre sensors.

    CSIR Research Space (South Africa)

    De Ponte, JD

    2014-05-01

    Full Text Available In order to meet the increasingly stringent requirements for wind tunnel balances, as expressed by the wind tunnel testing community, balance design philosophy needs to be further expanded to include alternative sensor, material, design...

  19. High-Resolution Wind Measurements for Offshore Wind Energy Development

    Science.gov (United States)

    Nghiem, Son V.; Neumann, Gregory

    2011-01-01

    A mathematical transform, called the Rosette Transform, together with a new method, called the Dense Sampling Method, have been developed. The Rosette Transform is invented to apply to both the mean part and the fluctuating part of a targeted radar signature using the Dense Sampling Method to construct the data in a high-resolution grid at 1-km posting for wind measurements over water surfaces such as oceans or lakes.

  20. Free flow wind speed from a blade-mounted flow sensor

    DEFF Research Database (Denmark)

    Pedersen, Mads Mølgaard; Larsen, Torben Juul; Aagaard Madsen, Helge

    2018-01-01

    This paper presents a method for obtaining the free-inflow velocities from a 3-D flow sensor mounted on the blade of a wind turbine. From its position on the rotating blade, e.g. one-third from the tip, a blade-mounted flow sensor (BMFS) is able to provide valuable information about the turbulent...... sheared inflow in different regions of the rotor. At the rotor, however, the inflow is affected by the wind turbine, and in most cases the wind of interest is the inflow that the wind turbine is exposed to, i.e. the free-inflow velocities. The current method applies a combination of aerodynamic models...... and procedures to estimate the induced velocities, i.e. the disturbance of the flow field caused by the wind turbine. These velocities are subtracted from the flow velocities measured by the BMFS to obtain the free-inflow velocities. Aeroelastic codes, like HAWC2, typically use a similar approach to calculate...

  1. Measurement of Ozone Production Sensor

    Directory of Open Access Journals (Sweden)

    M. Cazorla

    2010-05-01

    Full Text Available A new ambient air monitor, the Measurement of Ozone Production Sensor (MOPS, measures directly the rate of ozone production in the atmosphere. The sensor consists of two 11.3 L environmental chambers made of UV-transmitting Teflon film, a unit to convert NO2 to O3, and a modified ozone monitor. In the sample chamber, flowing ambient air is exposed to the sunlight so that ozone is produced just as it is in the atmosphere. In the second chamber, called the reference chamber, a UV-blocking film over the Teflon film prevents ozone formation but allows other processes to occur as they do in the sample chamber. The air flows that exit the two chambers are sampled by an ozone monitor operating in differential mode so that the difference between the two ozone signals, divided by the exposure time in the chambers, gives the ozone production rate. High-efficiency conversion of NO2 to O3 prior to detection in the ozone monitor accounts for differences in the NOx photostationary state that can occur in the two chambers. The MOPS measures the ozone production rate, but with the addition of NO to the sampled air flow, the MOPS can be used to study the sensitivity of ozone production to NO. Preliminary studies with the MOPS on the campus of the Pennsylvania State University show the potential of this new technique.

  2. Fiber optic pressure sensors in skin-friction measurements

    Science.gov (United States)

    Cuomo, F. W.

    1986-01-01

    A fiber optic lever sensing technique that can be used to measure normal pressure as well as shear stresses is discussed. This method uses three unequal fibers combining small size and good sensitivity. Static measurements appear to confirm the theoretical models predicted by geometrical optics and dynamic tests performed at frequencies up to 10 kHz indicate a flat response within this frequency range. These sensors are intended for use in a low speed wind tunnel environment.

  3. Fiber Laser for Wind Speed Measurements

    DEFF Research Database (Denmark)

    Olesen, Anders Sig

    This PhD thesis evaluates the practical construction and use of a Frequency Stepped Pulse Train modulated coherent Doppler wind lidar (FSPT lidar) for wind speed measurement. The concept of Doppler lidar is introduced as a means to measure line of sight wind speed by the Doppler shift of reflected...... Sweeper (LSFS) is introduced and analyzed as a light source for the FSPT lidar. The setup of the LSFS is discussed, and the necessary concepts for modeling and analyzing LSFS noise are developed. The model and measurements are then used to discuss the growth of optical noise in the LSFS and the impact...... on its use in the FSPT lidar. A complex ABCD model is developed and described as a method for calculating spatial and frequency dependency of a lidar’s signal strength. The model includes both spatial and temporal components of the lidar system, enabling a model capable of describing both CW, pulsed...

  4. A Wind Tunnel Study on the Mars Pathfinder (MPF) Lander Descent Pressure Sensor

    Science.gov (United States)

    Soriano, J. Francisco; Coquilla, Rachael V.; Wilson, Gregory R.; Seiff, Alvin; Rivell, Tomas

    2001-01-01

    The primary focus of this study was to determine the accuracy of the Mars Pathfinder lander local pressure readings in accordance with the actual ambient atmospheric pressures of Mars during parachute descent. In order to obtain good measurements, the plane of the lander pressure sensor opening should ideally be situated so that it is parallel to the freestream. However, due to two unfavorable conditions, the sensor was positioned in locations where correction factors are required. One of these disadvantages is due to the fact that the parachute attachment point rotated the lander's center of gravity forcing the location of the pressure sensor opening to be off tangent to the freestream. The second and most troublesome factor was that the lander descends with slight oscillations that could vary the amplitude of the sensor readings. In order to accurately map the correction factors required at each sensor position, an experiment simulating the lander descent was conducted in the Martian Surface Wind Tunnel at NASA Ames Research Center. Using a 115 scale model at Earth ambient pressures, the test settings provided the necessary Reynolds number conditions in which the actual lander was possibly subjected to during the descent. In the analysis and results of this experiment, the readings from the lander sensor were converted to the form of pressure coefficients. With a contour map of pressure coefficients at each lander oscillatory position, this report will provide a guideline to determine the correction factors required for the Mars Pathfinder lander descent pressure sensor readings.

  5. Intercalibration of HRDI and WINDII wind measurements

    Directory of Open Access Journals (Sweden)

    M. D. Burrage

    1997-09-01

    Full Text Available The High Resolution Doppler Imager (HRDI and the Wind Imaging Interferometer (WINDII in- struments, which are both on the Upper Atmosphere Research Satellite, measure winds by sensing the Doppler shift in atmospheric emission features. Because the two observation sets are frequently nearly coincident in space and time, each provides a very e.ective validation test of the other. Discrepancies due to geophysical di.erences should be much smaller than for comparisons with other techniques (radars, rockets, etc., and the very large sizes of the coincident data sets provide excellent statistics for the study. Issues that have been examined include relative systematic o.sets and the wind magnitudes obtained with the two systems. A significant zero wind position di.erence of ~6 m s–1 is identified for the zonal component, and it appears that this arises from an absolute perturbation in WINDII winds of –4 m s–1 and in HRDI of +2 m s–1. Altitude o.sets appear to be relatively small, and do not exceed 1 km. In addition, no evidence is found for the existence of a systematic wind speed bias between HRDI and WINDII. However, considerable day-to-day variability is found in the quality of the agreement, and RMS di.erences are surprisingly large, typically in the range of 20±30 m s–1.

  6. Intercalibration of HRDI and WINDII wind measurements

    Directory of Open Access Journals (Sweden)

    M. D. Burrage

    Full Text Available The High Resolution Doppler Imager (HRDI and the Wind Imaging Interferometer (WINDII in- struments, which are both on the Upper Atmosphere Research Satellite, measure winds by sensing the Doppler shift in atmospheric emission features. Because the two observation sets are frequently nearly coincident in space and time, each provides a very e.ective validation test of the other. Discrepancies due to geophysical di.erences should be much smaller than for comparisons with other techniques (radars, rockets, etc., and the very large sizes of the coincident data sets provide excellent statistics for the study. Issues that have been examined include relative systematic o.sets and the wind magnitudes obtained with the two systems. A significant zero wind position di.erence of ~6 m s–1 is identified for the zonal component, and it appears that this arises from an absolute perturbation in WINDII winds of –4 m s–1 and in HRDI of +2 m s–1. Altitude o.sets appear to be relatively small, and do not exceed 1 km. In addition, no evidence is found for the existence of a systematic wind speed bias between HRDI and WINDII. However, considerable day-to-day variability is found in the quality of the agreement, and RMS di.erences are surprisingly large, typically in the range of 20±30 m s–1.

  7. Noise measurements in 4 wind turbine farms

    International Nuclear Information System (INIS)

    Van Zuylen, E.J.; Koerts, M.

    1993-02-01

    The title wind turbine arrays are situated in Herbayum (Newinco 23PI250), Callantsoog (Bouma 160/20), Noordoostpolder (Windmaster WM300), and Ulketocht (Newinco 500 kW). Measurements were carried out by means of the so-called Ecofys Correlating Noise Meter to determine the source level of the wind turbines. The resulting source level as a function of the wind speed is interpolated to a source level for a wind speed of 8 m/s at 10 m height, on the basis of which the noise contours can be calculated. The noise contours are determined to analyze the noise load for people living in the neighbourhood of the wind parks. The source levels are compared with values as indicated in certificates, which are granted on the basis of a so-called Restricted Quality Certificate (BKC, abbreviated in Dutch) or the new standard NNI 6096/2 for the above-mentioned wind turbines. In general the results of this study agree quite well with the certified values. 12 figs., 7 tabs., 6 refs

  8. Aerial measuring system sensor modeling

    International Nuclear Information System (INIS)

    Detwiler, Rebecca

    2002-01-01

    The AMS fixed-wing and rotary-wing systems are critical National Nuclear Security Administration (NNSA) Emergency Response assets. This project is principally focused on the characterization of the sensors utilized with these systems via radiation transport calculations. The Monte Carlo N-Particle code (MCNP) which has been developed at Los Alamos National Laboratory was used to model the detector response of the AMS fixed wing and helicopter systems. To validate the calculations, benchmark measurements were made for simple source-detector configurations. The fixed-wing system is an important tool in response to incidents involving the release of mixed fission products (a commercial power reactor release), the threat or actual explosion of a Radiological Dispersal Device, and the loss or theft of a large industrial source (a radiography source). Calculations modeled the spectral response for the sensors contained, a 3-element NaI detector pod and HpGe detector, in the relevant energy range of 50 keV to 3 MeV. NaI detector responses were simulated for both point and distributed surface sources as a function of gamma energy and flying altitude. For point sources, photo-peak efficiencies were calculated for a zero radial distance and an offset equal to the altitude. For distributed sources approximating infinite plane, gross count efficiencies were calculated and normalized to a uniform surface deposition of 1 C i/m2

  9. Deflection estimation of a wind turbine blade using FBG sensors embedded in the blade bonding line

    International Nuclear Information System (INIS)

    Kim, Sang-Woo; Kang, Woo-Ram; Jeong, Min-Soo; Lee, In; Kwon, Il-Bum

    2013-01-01

    Estimating the deflection of flexible composite wind turbine blades is very important to prevent the blades from hitting the tower. Several researchers have used fiber Bragg grating (FBG) sensors—a type of optical fiber sensor (OFS)—to monitor the structural behavior of the blades. They can be installed on the surface and/or embedded in the interior of composites. However, the typical installation positions of OFSs present several problems, including delamination of sensing probes and a higher risk of fiber breakage during installation. In this study, we proposed using the bonding line between the shear web and spar cap as a new installation position of embedded OFSs for estimating the deflection of the blades. Laboratory coupon tests were undertaken preliminarily to confirm the strain measuring capability of embedded FBG sensors in adhesive layers, and the obtained values were verified by comparison with results obtained by electrical strain gauges and finite element analysis. We performed static loading tests on a 100 kW composite wind turbine blade to evaluate its deflections using embedded FBG sensors positioned in the bonding line. The deflections were estimated by classical beam theory considering a rigid body rotation near the tip of the blade. The evaluated tip deflections closely matched those measured by a linear variable differential transformer. Therefore, we verified the capability of embedded FBG sensors for evaluating the deflections of wind turbine blades. In addition, we confirmed that the bonding line between the shear web and spar cap is a practical location to embed the FBG sensors. (paper)

  10. Wind Atlas of Bay of Bengal with Satellite Wind Measurement

    DEFF Research Database (Denmark)

    Nadi, Navila Rahman

    footstep towards offshore wind energy analysis for this region. Generally, it is difficult to find offshore wind data relative to the wind turbine hub heights, therefore a starting point is necessary to identify the possible wind power density of the region. In such scenario, Synthetic aperture radars (SAR......The objective of this study is to obtain appropriate offshore location in the Bay of Bengal, Bangladesh for further development of wind energy. Through analyzing the previous published works, no offshore wind energy estimation has been found here. That is why, this study can be claimed as the first......) have proven useful. In this study, SAR based dataset- ENVISAT ASAR has been used for Wind Atlas generation. Furthermore, a comparative study has been performed with Global Wind Atlas (GWA) to determine a potential offshore wind farm. Additionally, the annual energy production of that offshore windfarm...

  11. Autonomous Aerial Sensors for Wind Power Meteorology - A Pre-Project

    DEFF Research Database (Denmark)

    Giebel, Gregor; Schmidt Paulsen, Uwe; Bange, Jens

    Autonomous Aerial Sensors, i.e. meteorological sensors mounted on Unmanned Aerial Systems UAS, can characterise the atmospheric flow in and around wind farms. We instrumented three planes, a helicopter and a lighter-than-air LTA system to fly one week together in a well-instrumented wind farm...

  12. Aerial Measuring System Sensor Modeling

    International Nuclear Information System (INIS)

    Detwiler, R.S.

    2002-01-01

    This project deals with the modeling the Aerial Measuring System (AMS) fixed-wing and rotary-wing sensor systems, which are critical U.S. Department of Energy's National Nuclear Security Administration (NNSA) Consequence Management assets. The fixed-wing system is critical in detecting lost or stolen radiography or medical sources, or mixed fission products as from a commercial power plant release at high flying altitudes. The helicopter is typically used at lower altitudes to determine ground contamination, such as in measuring americium from a plutonium ground dispersal during a cleanup. Since the sensitivity of these instruments as a function of altitude is crucial in estimating detection limits of various ground contaminations and necessary count times, a characterization of their sensitivity as a function of altitude and energy is needed. Experimental data at altitude as well as laboratory benchmarks is important to insure that the strong effects of air attenuation are modeled correctly. The modeling presented here is the first attempt at such a characterization of the equipment for flying altitudes. The sodium iodide (NaI) sensors utilized with these systems were characterized using the Monte Carlo N-Particle code (MCNP) developed at Los Alamos National Laboratory. For the fixed wing system, calculations modeled the spectral response for the 3-element NaI detector pod and High-Purity Germanium (HPGe) detector, in the relevant energy range of 50 keV to 3 MeV. NaI detector responses were simulated for both point and distributed surface sources as a function of gamma energy and flying altitude. For point sources, photopeak efficiencies were calculated for a zero radial distance and an offset equal to the altitude. For distributed sources approximating an infinite plane, gross count efficiencies were calculated and normalized to a uniform surface deposition of 1 microCi/m 2 . The helicopter calculations modeled the transport of americium-241 ( 241 Am) as this is

  13. Strain measurement using multiplexed fiber optic sensors

    International Nuclear Information System (INIS)

    Kwon, Il Bum; Kim, Chi Yeop; Yoon, Dong Jin; Lee, Seung Seok

    2003-01-01

    FBG(Fiber Bragg grating) sensor, which is one of the fiber optic sensors for the application of smart structures, can not only measure one specific point but also multiple points by multiplexing techniques. We have proposed a novel multiplexing technique of FBG sensor by the intensity modulation of light source. This technique is applicable to WDM(Wavelength Division Multiplexing) technique and number of sensors in this system can be increased by using this technique with WDM technique.

  14. Study of eddy current power loss from outer-winding coils of a magnetic position sensor

    International Nuclear Information System (INIS)

    Liu, C.-P.; Lin, T.-K.; Chang, Y.-H.; Yu, C.-S.; Wu, K.-T.; Wang, S.-J.; Ying, T.-F.; Huang, D.-R.

    2000-01-01

    The present analysis is concerned with eddy current power loss of a magnetic position sensor, which arises from a non-uniform flux linkage distribution between magnetic material and position sensor. In the paper, a magnetic position sensor system is simplified to be an outer-winding coil along the axial direction of a low carbon steel bar, and developed a numerical model to compute the electrical characteristics by an excited current source. According to the simulated and measured data in this proposed model from 2.52 to 11.37 Oes, eddy current power losses of conducting material have a variation of 6.1% and 9.77%, respectively. Finally, the phases of waveform of the induced output voltage will also be obtained in the conducting material, and have a variation of 3.68% obtained by using the current source in the proposed model

  15. Study of eddy current power loss from outer-winding coils of a magnetic position sensor

    CERN Document Server

    Liu, C P; Chang, Y H; Yu, C S; Wu, K T; Wang, S J; Ying, T F; Huang, D R

    2000-01-01

    The present analysis is concerned with eddy current power loss of a magnetic position sensor, which arises from a non-uniform flux linkage distribution between magnetic material and position sensor. In the paper, a magnetic position sensor system is simplified to be an outer-winding coil along the axial direction of a low carbon steel bar, and developed a numerical model to compute the electrical characteristics by an excited current source. According to the simulated and measured data in this proposed model from 2.52 to 11.37 Oes, eddy current power losses of conducting material have a variation of 6.1% and 9.77%, respectively. Finally, the phases of waveform of the induced output voltage will also be obtained in the conducting material, and have a variation of 3.68% obtained by using the current source in the proposed model.

  16. Wind Tunnel Measurements at Virginia Tech

    DEFF Research Database (Denmark)

    Fischer, Andreas; Bertagnolio, Franck

    2012-01-01

    In this section, the wind tunnel configuration used for aerodynamic and aeroacoustic measurement is described. Then, the validation of the method for evaluating far-field noise from surface microphones as described in Section 5 is presented. Finally, the design concept proposed in Section 6 is ve...

  17. Anemometers for Mars. [Viking '75 wind measurements

    Science.gov (United States)

    Henry, R. M.; Greene, G. C.

    1974-01-01

    An investigation is conducted concerning the problems involved in the conduction of wind measurements on the planet Mars, taking into account the currently known characteristics of the Martian atmosphere. Problems introduced by the presence of the lander are examined. The suitability of several different types of anemometers for making the measurements is discussed, giving attention to rotating anemometers, sonic anemometers, ion tracers, drag force anemometers, pitot tubes, and thermal anemometers.

  18. Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

    Directory of Open Access Journals (Sweden)

    Xingjun Lv

    2011-11-01

    Full Text Available In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

  19. Brillouin corrosion expansion sensors for steel reinforced concrete structures using a fiber optic coil winding method.

    Science.gov (United States)

    Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

    2011-01-01

    In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

  20. Wind-stilling in the light of wind speed measurements: the Czech experience

    Czech Academy of Sciences Publication Activity Database

    Brázdil, Rudolf; Valík, A.; Zahradníček, Pavel; Řezníčková, Ladislava; Tolasz, R.; Možný, M.

    2018-01-01

    Roč. 74 (2018), s. 131-143 ISSN 0936-577X R&D Projects: GA MŠk(CZ) LO1415; GA ČR(CZ) GA15-11805S Institutional support: RVO:86652079 Keywords : universal anemograph * vaisala wind-speed sensors * wind speed * homogenisation * wind stilling * Czech Republic Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Meteorology and atmospheric sciences Impact factor: 1.578, year: 2016

  1. Intelligent pressure measurement in multiple sensor arrays

    International Nuclear Information System (INIS)

    Matthews, C.A.

    1995-01-01

    Pressure data acquisition has typically consisted of a group of sensors scanned by an electronic or mechanical multiplexer. The data accuracy was dependent upon the temperature stability of the sensors. This paper describes a new method of pressure measurement that combines individual temperature compensated pressure sensors, a microprocessor, and an A/D converter in one module. Each sensor has its own temperature characteristics stored in a look-up table to minimize sensor thermal errors. The result is an intelligent pressure module that can output temperature compensated engineering units over an Ethernet interface. Calibration intervals can be dramatically extended depending upon system accuracy requirements and calibration techniques used

  2. FLEHAP: A Wind Powered Supply for Autonomous Sensor Nodes

    Directory of Open Access Journals (Sweden)

    Gregorio Boccalero

    2016-10-01

    Full Text Available The development of the Internet of Things infrastructure requires the deployment of millions of heterogeneous sensors embedded in the environment. The powering of these sensors cannot be done with wired connections, and the use of batteries is often impracticable. Energy harvesting is the common proposed solution, and many devices have been developed for this purpose, using light, mechanical vibrations, and temperature differences as energetic sources. In this paper we present a novel energy-harvester device able to capture the kinetic energy from a fluid in motion and transform it in electrical energy. This device, named FLEHAP (FLuttering Energy Harvester for Autonomous Powering, is based on an aeroelastic effect, named fluttering, in which a totally passive airfoil shows large and regular self-sustained motions (limit cycle oscillations even in extreme conditions (low Reynolds numbers, thanks to its peculiar mechanical configuration. This system shows, in some centimeter-sized configurations, an electrical conversion efficiency that exceeds 8% at low wind speed (3.5 m/s. By using a specialized electronic circuit, it is possible to store the electrical energy in a super capacitor, and so guarantee self-powering in such environmental conditions.

  3. Influence of wind conditions on wind turbine loads and measurement of turbulence using lidars

    NARCIS (Netherlands)

    Sathe, A.R.

    2012-01-01

    Variations in wind conditions influence the loads on wind turbines significantly. In order to determine these loads it is important that the external conditions are well understood. Wind lidars are well developed nowadays to measure wind profiles upwards from the surface. But how turbulence can be

  4. Sensor platform for gas composition measurement

    NARCIS (Netherlands)

    De Graaf, G.; Bakker, F.; Wolffenbuttel, R.F.

    2011-01-01

    The gas sensor research presented here has a focus on the measurement of the composition of natural gas and gases from sustainable resources, such as biogas. For efficient and safe combustion, new sensor systems need to be developed to measure the composition of these new gases. In general about 6

  5. Wireless sensor for temperature and humidity measurement

    Science.gov (United States)

    Drumea, Andrei; Svasta, Paul

    2010-11-01

    Temperature and humidity sensors have a broad range of applications, from heating and ventilation of houses to controlled drying of fruits, vegetables or meat in food industry. Modern sensors are integrated devices, usually MEMS, factory-calibrated and with digital output of measured parameters. They can have power down modes for reduced energy consumption. Such an integrated device allows the implementation of a battery powered wireless sensor when coupled with a low power microcontroller and a radio subsystem. A radio sensor can work independently or together with others in a radio network. Presented paper focuses mainly on measurement and construction aspects of sensors for temperature and humidity designed and implemented by authors; network aspects (communication between two or more sensors) are not analyzed.

  6. Measuring gas concentration and wind intensity in a turbulent wind tunnel with a mobile robot

    OpenAIRE

    Martínez Lacasa, Daniel; Moreno Blanc, Javier; Tresánchez, Marcel; Clotet Bellmunt, Eduard; Jiménez-Soto, Juan M.; Magrans, Rudys; Pardo Martínez, Antonio; Marco Colás, Santiago; Palacín Roca, Jordi

    2016-01-01

    This paper presents themeasurement of gas concentration and wind intensity performed with amobile robot in a customturbulent wind tunnel designed for experimentation with customizable wind and gas leak sources.This paper presents the representation in different information layers of the measurements obtained in the turbulent wind tunnel under different controlled environmental conditions in order to describe the plume of the gas and wind intensities inside the experimentation chamber...

  7. Gearbox Fault Diagnosis in a Wind Turbine Using Single Sensor Based Blind Source Separation

    Directory of Open Access Journals (Sweden)

    Yuning Qian

    2016-01-01

    Full Text Available This paper presents a single sensor based blind source separation approach, namely, the wavelet-assisted stationary subspace analysis (WSSA, for gearbox fault diagnosis in a wind turbine. Continuous wavelet transform (CWT is used as a preprocessing tool to decompose a single sensor measurement data into a set of wavelet coefficients to meet the multidimensional requirement of the stationary subspace analysis (SSA. The SSA is a blind source separation technique that can separate the multidimensional signals into stationary and nonstationary source components without the need for independency and prior information of the source signals. After that, the separated nonstationary source component with the maximum kurtosis value is analyzed by the enveloping spectral analysis to identify potential fault-related characteristic frequencies. Case studies performed on a wind turbine gearbox test system verify the effectiveness of the WSSA approach and indicate that it outperforms independent component analysis (ICA and empirical mode decomposition (EMD, as well as the spectral-kurtosis-based enveloping, for wind turbine gearbox fault diagnosis.

  8. 3D WindScanner lidar measurements of wind and turbulence around wind turbines, buildings and bridges

    Science.gov (United States)

    Mikkelsen, T.; Sjöholm, M.; Angelou, N.; Mann, J.

    2017-12-01

    WindScanner is a distributed research infrastructure developed at DTU with the participation of a number of European countries. The research infrastructure consists of a mobile technically advanced facility for remote measurement of wind and turbulence in 3D. The WindScanners provide coordinated measurements of the entire wind and turbulence fields, of all three wind components scanned in 3D space. Although primarily developed for research related to on- and offshore wind turbines and wind farms, the facility is also well suited for scanning turbulent wind fields around buildings, bridges, aviation structures and of flow in urban environments. The mobile WindScanner facility enables 3D scanning of wind and turbulence fields in full scale within the atmospheric boundary layer at ranges from 10 meters to 5 (10) kilometers. Measurements of turbulent coherent structures are applied for investigation of flow pattern and dynamical loads from turbines, building structures and bridges and in relation to optimization of the location of, for example, wind farms and suspension bridges. This paper presents our achievements to date and reviews briefly the state-of-the-art of the WindScanner measurement technology with examples of uses for wind engineering applications.

  9. Manufacturing technology of integrated textile-based sensor networks for in situ monitoring applications of composite wind turbine blades

    Science.gov (United States)

    Haentzsche, Eric; Mueller, Ralf; Huebner, Matthias; Ruder, Tristan; Unger, Reimar; Nocke, Andreas; Cherif, Chokri

    2016-10-01

    Based on in situ strain sensors consisting of piezo-resistive carbon filament yarns (CFYs), which have been successfully integrated into textile reinforcement structures during their textile-technological manufacturing process, a continuous load of fibre-reinforced plastic (FRP) components has been realised. These sensors are also suitable for structural health monitoring (SHM) applications. The two-dimensional sensor layout is made feasible by the usage of a modular warp yarn path manipulation unit. Using a functional model of a small wind turbine blade in thermoset composite design, the sensor function for basic SHM applications (e.g. static load monitoring) are demonstrated. Any mechanical loads along the pressure or suction side of the wind turbine blade can be measured and calculated via a correlative change in resistance of the CFYs within the textile reinforcement plies. Performing quasi-static load tests on both tensile specimen and full-scale wind turbine blade, elementary results have been obtained concerning electro-mechanical behaviour and spatial resolution of global and even local static stresses according to the CFY sensor integration length. This paper demonstrates the great potential of textile-based and textile-technological integrated sensors in reinforcement structures for future SHM applications of FRPs.

  10. Measurement campaign for wind power potential in west Greenland

    Science.gov (United States)

    Rønnow Jakobsen, Kasper

    2013-04-01

    . During the first years, the influence of instrument icing was not considered, but recently one of the sites was equipped with an ice rate sensor and a heated ultrasonic anemometer to study the ice influence. 3 Results The predominant wind direction for most sites is away from the ice cap at the center of the continent, but for some coastal sites it is north or south. The north-south wind pattern is expected from the synoptic patterns and the barrier effect of the ice cap. The sites where the predominant wind direction is away from the inland ice are dominated by katabatic wind systems from the ice cap and form valley systems. These sites also seem to have the highest wind resource and will be studied further. A good example of the influence of katabatic and thermal wind systems can be seen in the measurement data from Sarfannguit and Nanortalik 66 and 60 degrees northern latitude respectively. In future work, these katabatic flows and their impact on the wind resource will be studied using mesoscale modelling and microscale downscaling.

  11. Results of Sexbierum Wind Farm: single wake measurements

    NARCIS (Netherlands)

    Cleijne, J.W.

    1993-01-01

    In the framework of the JOULE-0064 'Full-scale Measurements in Wind Turbine Arrays' in the period between June-November 1992 measurements have been performed in the Sexbierum Wind Farm. The aim of the measurements is to provide data for the validation of wake and wind farm models, which are being

  12. Offshore wind resources at Danish measurement sites

    Energy Technology Data Exchange (ETDEWEB)

    Barthelmie, R J; Courtney, M S; Lange, B; Nielsen, M; Sempreviva, A M [Risoe National Lab., Dept. of Wind Energy and Atmospheric Physics, Roskilde (Denmark); Svenson, J; Olsen, F [SEAS, Haslev (Denmark); Christensen, T [Elsamprojekt, Fredericia (Denmark)

    1999-03-01

    In order to characterise wind and turbulence characteristics at prospective offshore wind energy sites, meteorological observations from a number of purpose-built offshore monitoring sites have been analyzed and compared with long wind speed time series. New analyses have been conducted on the data sets focussing on meteorology, turbulence, extreme winds and wind and wave interactions. Relationships between wind speed, turbulence and fetch are highly complex. Minimum turbulence intensity offshore is associated with wind speeds of about 12 m/s. At lower wind speeds, stability effects are important while at higher winds speeds wind and wave interactions appear to dominate. On average, turbulence intensity offshore at 48 m height is approximately 0.08 if no coastal effects are present. However, the effect of the coastal discontinuity persists in wind speed and turbulence characteristics for considerable distances offshore. The majority of the adjustment of appears to occur within 20 km of the coast. (au)

  13. Full scale measurement of wind induced pressures : 1 configuration of wind induced pressures

    NARCIS (Netherlands)

    Geurts, C.P.W.; Wijen, H.L.M.

    1994-01-01

    A research project 10 the spectral characteristics of wind induced pressures is in progress in Eindhoven. This project includes both wind tunnel and full scale measurements. Wind induced pressures are measured in full scale at the main building of Eindhoven University of Technology. This paper

  14. Measurements of Waves in a Wind-wave Tank Under Steady and Time-varying Wind Forcing.

    Science.gov (United States)

    Zavadsky, Andrey; Shemer, Lev

    2018-02-13

    This manuscript describes an experimental procedure that allows obtaining diverse quantitative information on temporal and spatial evolution of water waves excited by time-dependent and steady wind forcing. Capacitance-type wave gauge and Laser Slope Gauge (LSG) are used to measure instantaneous water surface elevation and two components of the instantaneous surface slope at a number of locations along the test section of a wind-wave facility. The computer-controlled blower provides airflow over the water in the tank whose rate can vary in time. In the present experiments, the wind speed in the test section initially increases quickly from rest to the set value. It is then kept constant for the prescribed duration; finally, the airflow is shut down. At the beginning of each experimental run, the water surface is calm and there is no wind. Operation of the blower is initiated simultaneously with the acquisition of data provided by all sensors by a computer; data acquisition continues until the waves in the tank fully decay. Multiple independent runs performed under identical forcing conditions allow determining statistically reliable ensemble-averaged characteristic parameters that quantitatively describe wind-waves' variation in time for the initial development stage as a function of fetch. The procedure also allows characterizing the spatial evolution of the wave field under steady wind forcing, as well as decay of waves in time, once the wind is shut down, as a function of fetch.

  15. ALADIN: an atmospheric laser Doppler wind lidar instrument for wind velocity measurements from space

    Science.gov (United States)

    Krawczyk, R.; Ghibaudo, JB.; Labandibar, JY.; Willetts, D.; Vaughan, M.; Pearson, G.; Harris, M.; Flamant, P. H.; Salamitou, P.; Dabas, A.; Charasse, R.; Midavaine, T.; Royer, M.; Heimel, H.

    2018-04-01

    This paper, "ALADIN: an atmospheric laser Doppler wind lidar instrument for wind velocity measurements from space," was presented as part of International Conference on Space Optics—ICSO 1997, held in Toulouse, France.

  16. Electrical Impedance Measurements of PZT Nanofiber Sensors

    Directory of Open Access Journals (Sweden)

    Richard Galos

    2017-01-01

    Full Text Available Electrical impedance measurements of PZT nanofiber sensors were performed using a variety of methods over a frequency spectrum ranging from DC to 1.8 GHz. The nanofibers formed by electrospinning with diameters ranging from 10 to 150 nm were collected and integrated into sensors using microfabrication techniques. Special matching circuits with ultrahigh input impedance were fabricated to produce low noise, measurable sensor outputs. Material properties including resistivity and dielectric constant are derived from the impedance measurements. The resulting material properties are also compared with those of individual nanofibers being tested using conductive AFM and Scanning Conductive Microscopy.

  17. Damage detection of rotating wind turbine blades using local flexibility method and long-gauge fiber Bragg grating sensors

    Science.gov (United States)

    Hsu, Ting-Yu; Shiao, Shen-Yuan; Liao, Wen-I.

    2018-01-01

    Wind turbines are a cost-effective alternative energy source; however, their blades are susceptible to damage. Therefore, damage detection of wind turbine blades is of great importance for condition monitoring of wind turbines. Many vibration-based structural damage detection techniques have been proposed in the last two decades. The local flexibility method, which can determine local stiffness variations of beam-like structures by using measured modal parameters, is one of the most promising vibration-based approaches. The local flexibility method does not require a finite element model of the structure. A few structural modal parameters identified from the ambient vibration signals both before and after damage are required for this method. In this study, we propose a damage detection approach for rotating wind turbine blades using the local flexibility method based on the dynamic macro-strain signals measured by long-gauge fiber Bragg grating (FBG)-based sensors. A small wind turbine structure was constructed and excited using a shaking table to generate vibration signals. The structure was designed to have natural frequencies as close as possible to those of a typical 1.5 MW wind turbine in real scale. The optical fiber signal of the rotating blades was transmitted to the data acquisition system through a rotary joint fixed inside the hollow shaft of the wind turbine. Reversible damage was simulated by aluminum plates attached to some sections of the wind turbine blades. The damaged locations of the rotating blades were successfully detected using the proposed approach, with the extent of damage somewhat over-estimated. Nevertheless, although the specimen of wind turbine blades cannot represent a real one, the results still manifest that FBG-based macro-strain measurement has potential to be employed to obtain the modal parameters of the rotating wind turbines and then locations of wind turbine segments with a change of rigidity can be estimated effectively by

  18. Automatic tracking of wake vortices using ground-wind sensor data

    Science.gov (United States)

    1977-01-03

    Algorithms for automatic tracking of wake vortices using ground-wind anemometer : data are developed. Methods of bad-data suppression, track initiation, and : track termination are included. An effective sensor-failure detection-and identification : ...

  19. 3D WindScanner lidar measurements of wind and turbulence around wind turbines, buildings and bridges

    DEFF Research Database (Denmark)

    Mikkelsen, Torben Krogh; Sjöholm, Mikael; Angelou, Nikolas

    2017-01-01

    WindScanner is a distributed research infrastructure developed at DTU with the participation of a number of European countries. The research infrastructure consists of a mobile technically advanced facility for remote measurement of wind and turbulence in 3D. The WindScanners provide coordinated...... structures and of flow in urban environments. The mobile WindScanner facility enables 3D scanning of wind and turbulence fields in full scale within the atmospheric boundary layer at ranges from 10 meters to 5 (10) kilometers. Measurements of turbulent coherent structures are applied for investigation...

  20. Acoustic and geophysical measurement of infrasound from turbines at wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Hepburn, H.G. [Hepburn Exploration Inc., Canmore, AB (Canada)

    2005-07-01

    An experiment was conducted at the Castle River Wind Farm in southern Alberta to measure and characterize infrasound from the turbines. The wind farm contains one 600 MW turbine and fifty-nine 660 MW wind turbines. Three types of sensors were used to measure both the low and high frequency acoustic energy and geophysical sound levels. These included low frequency geophones, acoustic microphones and a precision sound analyzer. Data was recorded for low, medium and high wind states, with the entire wind turbine array operating, and with the entire wind farm stopped. Downwind telemetry measurements were recorded for 30 continuous 50 metre offsets, up to a distance of 1450 metres from the wind farm. The objective of the project was to characterize the ambient noise levels and sound emitted by the turbines. Measurements were taken for wind speed and direction, atmospheric pressure, atmospheric temperature and turbine related data. Visual observations included atmospheric conditions, extraneous sources of noise such as aircraft, trains, motor vehicle traffic, highway noise, bird song, crickets and the rotational state of the turbines. It was concluded that for studying low frequency sound, the linear dB scale should be used instead of the dBA scale. Measurements of frequencies down to 6.3 Hz, showed that infrasound emission from the Castle River Wind Farm is not a significant concern. Lower frequencies down to about 2.5 Hz also confirmed that infrasound emissions are not significantly above the ambient noise levels. Any infrasound emissions were strongly coupled to the ground and were attenuated quickly. Time domain measurements showed that at all wind speeds and for frequencies up to 270 Hz, wind noise was actually attenuated when the wind farm is in operation. The noise levels were higher when the turbines were not turning. This finding was confirmed through spectral analysis. 12 refs., 2 tabs., 46 figs.

  1. Analysis of Anholt offshore wind farm SCADA measurements

    DEFF Research Database (Denmark)

    Hansen, Kurt Schaldemose; Volker, Patrick; Pena Diaz, Alfredo

    SCADA measurements from the Danish Anholt offshore wind farm (ANH) for a period of 2½ years have been qualified. ANH covers 12 km × 22 km and is located between Djursland and the island Anholt in Kattegat, Denmark. This qualification encompasses identification of curtailment and idling periods......, start/stop events and a power curve control for each wind turbine in the wind farm. Data also include wind speed measurements from a nearby WindCube lidar and simulations from the WRF model for the same period as the SCADA. An equivalent wind speed (wsi) is derived from the combined power and pitch...

  2. A MEMS sensor for microscale force measurements

    International Nuclear Information System (INIS)

    Majcherek, S; Aman, A; Fochtmann, J

    2016-01-01

    This paper describes the development and testing of a new MEMS-based sensor device for microscale contact force measurements. A special MEMS cell was developed to reach higher lateral resolution than common steel-based load cells with foil-type strain gauges as mechanical-electrical converters. The design provided more than one normal force measurement point with spatial resolution in submillimeter range. Specific geometric adaption of the MEMS-device allowed adjustability of its measurement range between 0.5 and 5 N. The thin film nickel-chromium piezo resistors were used to achieve a mechanical-electrical conversion. The production process was realized by established silicon processing technologies such as deep reactive ion etching and vapor deposition (sputtering). The sensor was tested in two steps. Firstly, the sensor characteristics were carried out by application of defined loads at the measurement points by a push-pull tester. As a result, the sensor showed linear behavior. A measurement system analysis (MSA1) was performed to define the reliability of the measurement system. The measured force values had the maximal relative deviation of 1% to average value of 1.97 N. Secondly, the sensor was tested under near-industrial conditions. In this context, the thermal induced relaxation behavior of the electrical connector contact springs was investigated. The handling of emerging problems during the characterization process of the sensor is also described. (paper)

  3. Doppler Wind Lidar Measurements and Scalability to Space

    Data.gov (United States)

    National Aeronautics and Space Administration — Global measurements of wind speed and direction from Doppler wind lidars, if available, would significantly improve forecasting of severe weather events such as...

  4. Compact, High Energy 2-micron Coherent Doppler Wind Lidar Development for NASA's Future 3-D Winds Measurement from Space

    Science.gov (United States)

    Singh, Upendra N.; Koch, Grady; Yu, Jirong; Petros, Mulugeta; Beyon, Jeffrey; Kavaya, Michael J.; Trieu, Bo; Chen, Songsheng; Bai, Yingxin; Petzar, paul; hide

    2010-01-01

    This paper presents an overview of 2-micron laser transmitter development at NASA Langley Research Center for coherent-detection lidar profiling of winds. The novel high-energy, 2-micron, Ho:Tm:LuLiF laser technology developed at NASA Langley was employed to study laser technology currently envisioned by NASA for future global coherent Doppler lidar winds measurement. The 250 mJ, 10 Hz laser was designed as an integral part of a compact lidar transceiver developed for future aircraft flight. Ground-based wind profiles made with this transceiver will be presented. NASA Langley is currently funded to build complete Doppler lidar systems using this transceiver for the DC-8 aircraft in autonomous operation. Recently, LaRC 2-micron coherent Doppler wind lidar system was selected to contribute to the NASA Science Mission Directorate (SMD) Earth Science Division (ESD) hurricane field experiment in 2010 titled Genesis and Rapid Intensification Processes (GRIP). The Doppler lidar system will measure vertical profiles of horizontal vector winds from the DC-8 aircraft using NASA Langley s existing 2-micron, pulsed, coherent detection, Doppler wind lidar system that is ready for DC-8 integration. The measurements will typically extend from the DC-8 to the earth s surface. They will be highly accurate in both wind magnitude and direction. Displays of the data will be provided in real time on the DC-8. The pulsed Doppler wind lidar of NASA Langley Research Center is much more powerful than past Doppler lidars. The operating range, accuracy, range resolution, and time resolution will be unprecedented. We expect the data to play a key role, combined with the other sensors, in improving understanding and predictive algorithms for hurricane strength and track. 1

  5. Wind turbine power performance measurement with the use of spinner anemometry

    DEFF Research Database (Denmark)

    Demurtas, Giorgio

    The spinner anemometer was patented by DTU in 2004 and licenced to ROMO Wind in 2011. By 2015 the spinner anemometer was installed on several hundred wind turbines for yaw misalignment measurements. The goal of this PhD project was to investigate the feasibility of use of spinner anemometry......-mast and spinner anemometer were then compared. Application of the NTF from one turbine to the other was made with a difference of only 0.38% in AEP. Different methods of analysis of fast sampled measurements such as the Langevin power curve were tested, concluding that the method of bins (IEC61400...... measurements was further improved with an innovation step to calibrate without use of the yaw position sensor, saving cost and time of installing the additional yaw sensor. The so called "wind speed response method" was validated by comparing 27 different calibration tests to the fist methods. This method...

  6. Dynamic temperature measurements with embedded optical sensors.

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Daniel H.,; Seagle, Christopher T; Ao, Tommy

    2013-10-01

    This report summarizes LDRD project number 151365, \\Dynamic Temperature Measurements with Embedded Optical Sensors". The purpose of this project was to develop an optical sensor capable of detecting modest temperature states (<1000 K) with nanosecond time resolution, a recurring diagnostic need in dynamic compression experiments at the Sandia Z machine. Gold sensors were selected because the visible re ectance spectrum of gold varies strongly with temperature. A variety of static and dynamic measurements were performed to assess re ectance changes at di erent temperatures and pressures. Using a minimal optical model for gold, a plausible connection between static calibrations and dynamic measurements was found. With re nements to the model and diagnostic upgrades, embedded gold sensors seem capable of detecting minor (<50 K) temperature changes under dynamic compression.

  7. A Fault Diagnostic Method for Position Sensor of Switched Reluctance Wind Generator

    DEFF Research Database (Denmark)

    Wang, Chao; Liu, Xiao; Liu, Hui

    2016-01-01

    Fast and accurate fault diagnosis of the position sensor is of great significance to ensure the reliability as well as sensor fault tolerant operation of the Switched Reluctance Wind Generator (SRWG). This paper presents a fault diagnostic scheme for a SRWG based on the residual between the estim...

  8. Electromagnetic sensors for monitoring of scour and deposition processes at bridges and offshore wind turbines

    Science.gov (United States)

    Michalis, Panagiotis; Tarantino, Alessandro; Judd, Martin

    2014-05-01

    Recent increases in precipitation have resulted in severe and frequent flooding incidents. This has put hydraulic structures at high risk of failure due to scour, with severe consequences to public safety and significant economic losses. Foundation scour is the leading cause of bridge failures and one of the main climate change impacts to highway and railway infrastructure. Scour action is also being considered as a major risk for offshore wind farm developments as it leads to excessive excavation of the surrounding seabed. Bed level conditions at underwater foundations are very difficult to evaluate, considering that scour holes are often re-filled by deposited loose material which is easily eroded during smaller scale events. An ability to gather information concerning the evolution of scouring will enable the validation of models derived from laboratory-based studies and the assessment of different engineering designs. Several efforts have focused on the development of instrumentation techniques to measure scour processes at foundations. However, they are not being used routinely due to numerous technical and cost issues; therefore, scour continues to be inspected visually. This research project presents a new sensing technique, designed to measure scour depth variation and sediment deposition around the foundations of bridges and offshore wind turbines, and to provide an early warning of an impending structural failure. The monitoring system consists of a probe with integrated electromagnetic sensors, designed to detect the change in the surrounding medium around the foundation structure. The probe is linked to a wireless network to enable remote data acquisition. A developed prototype and a commercial sensor were evaluated to quantify their capabilities to detect scour and sediment deposition processes. Finite element modelling was performed to define the optimum geometric characteristics of the prototype scour sensor based on models with various permittivity

  9. Advanced load alleviation for wind turbines using adaptive trailing edge flaps: Sensoring and control

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Peter Bjoern

    2010-02-15

    The purpose of wind turbines and their predecessors the windmill, is to convert the energy in the wind to usable energy forms. Whereas windmills of the past focused on the conversion of wind power to torque for grinding, pumping and winching, modern wind turbines convert the wind energy into electric power. They do so through incorporation of generators, which convert mechanical torque into electricity. Wind turbines are designed to keep the overall cost per produced Kilo Watt hour as low as possible. One way of improving the performance and lifetime of the wind turbine is through active flow control. Active control is often considered costly but if the lifespan of the components can be increased it could be justifiable. This thesis covers various aspects of 'smart control' such as control theory, sensoring, optimization, experiments and numerical modeling. (author)

  10. Acoustic Emission Stethoscope - Measurements with Acoustic Emission on Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Krystof Kryniski [AaF Infrastructure, Stockholm (Sweden)

    2013-02-15

    A remote ultrasonic stethoscope, designed on mobile devices to help a maintenance team in diagnosing drive train problems, has been demonstrated. By implementing an acoustic emission technology, the operating conditions of wind turbines have been assessed by trending techniques and ultrasonic acoustic emission converted into audible sound. The new approach has been developed and tested and compared to other monitoring techniques. Acoustic emission has generally been shown to provide a number of advantages over vibration and shock pulse methods because the system is operating in a substantially higher frequency range (100 kHz) and therefore it is more immune to operation of surrounding machines and components. Quick attenuation of ultrasonic propagation waves in the drive-train structure helps to pin-point the origin of any fault as the signals are sharper and more pronounced. Further, with the intensity measurements a direction of the source of ultrasonic energy can be identified. Using a high frequency thus makes the method suitable for measuring local effects and to determine local defects since the disturbing signals from other parts are damped. Recently developed programmable sensors capable of processing signals onboard, producing quality outputs with extremely low noise-to-signal ratio, have been used. It is discussed how the new approach can lower the cost of a wind-turbine monitoring system, while at the same time making it simple and more reliable, see Appendix A. The method has been tested on rotating parts of wind-turbines, including traditionally difficult areas such as low speed main bearings and planetary gearboxes. The method developed in the project was designed to see physical processes such as friction, impacts and metal removal, occurring when machinery degrades, can be detected and notified with the developed notification system. Apart from reporting the status and displaying the changes of the pre-defined parameters or symptoms, the system has

  11. Comparison of 3D turbulence measurements using three staring wind lidars and a sonic anemometer

    DEFF Research Database (Denmark)

    Mann, Jakob; Cariou, J.-P.; Courtney, Michael

    2008-01-01

    Three pulsed lidars were used in staring, non-scanning mode, placed so that their beams crossed close to a 3D sonic anemometer. The goal is to compare lidar volume averaged wind measurement with point measurement reference sensors and to demonstrate the feasibility of performing 3D turbulence mea...... measurements with lidars. The results show a very good correlation between the lidar and the sonic times series. The variance of the velocity measured by the Mar is attenuated due to spatial filtering, and the amount of attenuation can be predicted theoretically.......Three pulsed lidars were used in staring, non-scanning mode, placed so that their beams crossed close to a 3D sonic anemometer. The goal is to compare lidar volume averaged wind measurement with point measurement reference sensors and to demonstrate the feasibility of performing 3D turbulence...

  12. On the energy pattern factor in wind measurements

    Energy Technology Data Exchange (ETDEWEB)

    Buick, T R; Doherty, M A; McMullan, J.T., Morgan, R.; Murray, R B

    1977-01-01

    Measurements of energy pattern factor K/sub e/ were made using a continuous-analogue wind-power metering technique, rather than by the more usual sampling procedure. The values obtained were significantly larger than the usually accepted figure. The discrepancy is attributed partly to the method of measurement, which includes the actual power present rather than the amount that can be extracted, and partly to the use of rather more typical wind speeds. It is concluded, however, that more energy can be derived from wind schemes than was thought, even during periods of light wind. These conclusions improve the viability of wind power plants.

  13. Optical sensor for measuring American Lobster vitality

    International Nuclear Information System (INIS)

    Tomassetti, Brian R. A.; Vetelino, John F.

    2011-01-01

    The vitality of the American Lobster (Homarus americanus) is correlated to the total hemolymph protein (THP) in lobster hemolymph (blood). The standard technique for determining lobster vitality is to draw blood from a lobster and measure THP with a refractometer. This technique is invasive and endangers the lobster's health since blood must be drawn from the lobster. In the present work an optical sensor is developed to measure a lobster's vitality in vivo. It is comprised of a broadband light source, a monochromator, a fiber optic reflection probe, a spectrometer and a computer. This sensor measures protein concentrations by exciting a lobster with 280 nm and 334 nm wavelength light sources and measuring the corresponding absorbance peaks for THP and the fluorescence peak for hemocyanin (Hc), the majority protein in hemolymph. In this work several lobsters are tested. For each lobster, absorbance and fluorescence peaks are measured using the sensor and compared to protein concentrations measured using a refractometer. It is found that the shell thickness and muscle density, which correspond directly to protein concentration and the molting stage of the lobster have a significant effect on the absorbance and fluorescence measurements. It is also found that within specific molting stages, such as pre-molt and post-molt, protein concentration measured with a refractometer correlates linearly to absorbance and fluorescence measurements with the optical sensor.

  14. Optical Sensor for Measuring American Lobster Vitality

    Science.gov (United States)

    Tomassetti, Brian R. A.; Vetelino, John F.

    2011-06-01

    The vitality of the American Lobster (Homarus americanus) is correlated to the total hemolymph protein (THP) in lobster hemolymph (blood). The standard technique for determining lobster vitality is to draw blood from a lobster and measure THP with a refractometer. This technique is invasive and endangers the lobster's health since blood must be drawn from the lobster. In the present work an optical sensor is developed to measure a lobster's vitality in vivo. It is comprised of a broadband light source, a monochromator, a fiber optic reflection probe, a spectrometer and a computer. This sensor measures protein concentrations by exciting a lobster with 280 nm and 334 nm wavelength light sources and measuring the corresponding absorbance peaks for THP and the fluorescence peak for hemocyanin (Hc), the majority protein in hemolymph. In this work several lobsters are tested. For each lobster, absorbance and fluorescence peaks are measured using the sensor and compared to protein concentrations measured using a refractometer. It is found that the shell thickness and muscle density, which correspond directly to protein concentration and the molting stage of the lobster have a significant effect on the absorbance and fluorescence measurements. It is also found that within specific molting stages, such as pre-molt and post-molt, protein concentration measured with a refractometer correlates linearly to absorbance and fluorescence measurements with the optical sensor.

  15. Wind Atlas for South Africa (WASA). Report on Measurements

    DEFF Research Database (Denmark)

    Mabille, Eugéne; Prinsloo, Eric; Mortensen, Niels Gylling

    , to verify the results of the meso-scale modelling. The Measurements work package (WP2) is one of six work packages that collectively make up the Wind Atlas for South Africa (WASA) project. The measurements also provide observed wind climates at the measurement sites, which can be used by micrositing...... to be commissioned was WM06 (Sutherland) and this was completed on 17 September 2010. The outputs of WP2 are: i. Establish 10 high quality wind measurement stations providing three years of measurement data for calibration of the mesoscale modelling. ii. A database system for wind data collection and on-line Web...

  16. On mean wind and turbulence profile measurements from ground-based wind lidars

    DEFF Research Database (Denmark)

    Mikkelsen, Torben

    2009-01-01

    Two types of wind lidar?s have become available for ground-based vertical mean wind and turbulence profiling. A continuous wave (CW) wind lidar, and a pulsed wind lidar. Although they both are build upon the same recent 1.55 μ telecom fibre technology, they possess fundamental differences between...... their temporal and spatial resolution capabilities. A literature review of the two lidar systems spatial and temporal resolution characteristics will be presented, and the implication for the two lidar types vertical profile measurements of mean wind and turbulence in the lower atmospheric boundary layer...

  17. Microparticle impact sensor measures energy directly

    Science.gov (United States)

    Alexander, W. M.; Berg, O. E.

    1965-01-01

    Construction of a capacitor sensor consisting of a dielectric layer between two conductive surface layers and connected across a potential source through a sensing resistor permits measurement of energy of impinging particles without degradation of sensitivity. A measurable response is produced without penetration of the dielectric layer.

  18. Near DC force measurement using PVDF sensors

    Science.gov (United States)

    Ramanathan, Arun Kumar; Headings, Leon M.; Dapino, Marcelo J.

    2018-03-01

    There is a need for high-performance force sensors capable of operating at frequencies near DC while producing a minimal mass penalty. Example application areas include steering wheel sensors, powertrain torque sensors, robotic arms, and minimally invasive surgery. The beta crystallographic phase polyvinylidene fluoride (PVDF) films are suitable for this purpose owing to their large piezoelectric constant. Unlike conventional capacitive sensors, beta crystallographic phase PVDF films exhibit a broad linear range and can potentially be designed to operate without complex electronics or signal processing. A fundamental challenge that prevents the implementation of PVDF in certain high-performance applications is their inability to measure static signals, which results from their first-order electrical impedance. Charge readout algorithms have been implemented which address this issue only partially, as they often require integration of the output signal to obtain the applied force profile, resulting in signal drift and signal processing complexities. In this paper, we propose a straightforward real time drift compensation strategy that is applicable to high output impedance PVDF films. This strategy makes it possible to utilize long sample times with a minimal loss of accuracy; our measurements show that the static output remains within 5% of the original value during half-hour measurements. The sensitivity and full-scale range are shown to be determined by the feedback capacitance of the charge amplifier. A linear model of the PVDF sensor system is developed and validated against experimental measurements, along with benchmark tests against a commercial load cell.

  19. Wind gust measurements using pulsed Doppler wind-lidar: comparison of direct and indirect techniques

    DEFF Research Database (Denmark)

    The measurements of wind gusts, defined as short duration wind speed maxima, have traditionally been limited by the height that can be reached by weather masts. Doppler lidars can potentially provide information from levels above this and thereby fill this gap in our knowledge. To measure the 3D...... is 3.9 s) which can provide high resolution turbulent measurements, both in the vertical direction, and potentially in the horizontal direction. In this study we explore different strategies of wind lidar measurements to measure the wind speed maxima. We use a novel stochastic turbulence reconstruction...... model, driven by the Doppler lidar measurements, which uses a non-linear particle filter to estimate the small-scale turbulent fluctuations. The first results show that the reconstruction method can reproduce the wind speed maxima measured by the sonic anemometer if a low-pass filter with a cut...

  20. Unknown input observer based detection of sensor faults in a wind turbine

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2010-01-01

    In this paper an unknown input observer is designed to detect three different sensor fault scenarios in a specified bench mark model for fault detection and accommodation of wind turbines. In this paper a subset of faults is dealt with, it are faults in the rotor and generator speed sensors as well...... as a converter sensor fault. The proposed scheme detects the speed sensor faults in question within the specified requirements given in the bench mark model, while the converter fault is detected but not within the required time to detect....

  1. Hot Wire Anemometer Turbulence Measurements in the wind Tunnel of LM Wind Power

    DEFF Research Database (Denmark)

    Fischer, Andreas

    downstream of the nozzle contraction. We used two different hot wire probes: a dual sensor miniature wire probe (Dantec 55P61) and a triple sensor fiber film probe (Dantec 55R91). The turbulence intensity measured with the dual sensor probe in the empty tunnel section was significantly lower than the one...

  2. Standards for measurements and testing of wind turbine power quality

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, P [Risoe National Lab., Roskilde (Denmark); Gerdes, G; Klosse, R; Santjer, F [DEWI, Wilhelmshaven (Germany); Robertson, N; Davy, W [NEL, Glasgow (United Kingdom); Koulouvari, M; Morfiadakis, E [CRES, Pikermi (Greece); Larsson, Aa [Chalmers Univ. of Technology, Goeteborg (Sweden)

    1999-03-01

    The present paper describes the work done in power quality sub-task of the project `European Wind Turbine Testing Procedure Developments` funded by the EU SMT program. The objective of the power quality sub-task has been to make analyses and new recommendation(s) for the standardisation of measurement and verification of wind turbine power quality. The work has been organised in three major activities. The first activity has been to propose measurement procedures and to verify existing and new measurement procedures. This activity has also involved a comparison of the measurements and data processing of the participating partners. The second activity has been to investigate the influence of terrain, grid properties and wind farm summation on the power quality of wind turbines with constant rotor speed. The third activity has been to investigate the influence of terrain, grid properties and wind farm summation on the power quality of wind turbines with variable rotor speed. (au)

  3. An energy harvesting system using the wind-induced vibration of a stay cable for powering a wireless sensor node

    International Nuclear Information System (INIS)

    Jung, Hyung-Jo; Kim, In-Ho; Jang, Seon-Jun

    2011-01-01

    This paper proposes an electromagnetic energy harvesting system, which utilizes the wind-induced vibration of a stay cable, and investigates its feasibility for powering a wireless sensor node on the cable through numerical simulations as well as experimental tests. To this end, the ambient acceleration responses of a stay cable installed in an in-service cable-stayed bridge are measured, and then they are used as input excitations in cases of both numerical simulations and experimental tests to evaluate the performance of the proposed energy harvesting system. The results of the feasibility test demonstrate that the proposed system generates sufficient electricity for operation of a wireless sensor node attached on the cable under the moderate wind conditions

  4. Sensor for Viscosity and Shear Strength Measurement

    International Nuclear Information System (INIS)

    Dillon, J.; Moore, J.E. Jr.; Ebadian, M.A.; Jones, W.K.

    1998-01-01

    Measurement of the physical properties (viscosity and density) of waste slurries is critical in evaluating transport parameters to ensure turbulent flow through transport pipes. The environment for measurement and sensor exposure is extremely harsh; therefore, reliability and ruggedness are critical in the sensor design. The work for this project will be performed in three phases. The first phase, carried out in FY96, involved (1) an evaluation of acoustic and other methods for viscosity measurement; (2) measurement of the parameters of slurries over the range of percent solids found in tanks and transport systems; (3) a comparison of physical properties (e.g., viscosity and density) to percent solids found composition; and (4) the design of a prototype sensor. The second phase (FY97) will involve the fabrication of a prototype hybrid sensor to measure the viscosity and mechanical properties of slurries in remote, high-radiation environments. Two different viscometer designs are being investigated in this study: a magnetostrictive pulse wave guide viscometer; an oscillating cylinder viscometer. In FY97, the Hemispheric Center for Environmental Technology (HCET) at Florida International University (FIU), which has printed circuit, thick film, thin film, and co-fired ceramic fabrication capability, will fabricate five probes for demonstration after technology selection and evaluation

  5. Fundamentals for remote structural health monitoring of wind turbine blades - a preproject. Annex E. Full-scale test of wind turbine blade, using sensors and NDT

    DEFF Research Database (Denmark)

    Kristensen, O.J.D.; McGugan, Malcolm; Sendrup, P.

    2002-01-01

    A 19.1 metre wind turbine blade was subjected to static tests. The purpose of the test series was to verify the abilities of different types of sensors to detect damage in wind turbine blades. Prior to each of the static test-series an artificial damagewas made on the blade. The damage made...... for each test-series was surveyed during each series by acoustic emission, fiber optic micro bend displacement transducers and strain gauges. The propagation of the damage was determined by use of ultra sonic andX-ray surveillance during stops in the test-series. By use of acoustic emission it was possible...... to measure damage propagation before the propagation was of visible size. By use of fiber optic micro bend displacement transducers and strain gauges it waspossible to measure minor damage propagation. By use of both ultra sonic, and X-ray NDT-equipment it were possible to determine the size of propagated...

  6. Autonomous aerial sensors for wind power meteorology - A pre-project

    Energy Technology Data Exchange (ETDEWEB)

    Giebel, G. (ed.); Schmidt Paulsen, U.; Bange, J.; la Cour-Harbo, A.; Reuder, J.; Mayer, S.; van der Kroonenberg, A.; Moelgaard, J.

    2012-01-15

    Autonomous Aerial Sensors, i.e. meteorological sensors mounted on Unmanned Aerial Systems UAS, can characterise the atmospheric flow in and around wind farms. We instrumented three planes, a helicopter and a lighter-than-air LTA system to fly one week together in a well-instrumented wind farm, partly with nano-synchronised sensors (time stamped with about 100 ns global accuracy). Between bankruptcy of a partner, denied overflight rights at the main test location, denied Civil Aviation Authorities permits at the alternative location, stolen planes, and crashed UAS we managed to collect data at a wind farm in Lolland and on an atmospheric campaign in France. Planning of an offshore campaign using the developed techniques is underway. (Author)

  7. Measuring method for optical fibre sensors

    NARCIS (Netherlands)

    Lammerink, Theodorus S.J.; Fluitman, J.H.J.

    1984-01-01

    A new measuring method for the signal amplitude in intensity modulating fibre optic sensors is described. A reference signal is generated in the time domain. The method is insensitive for the sensitivity fluctuations of the light transmitter and the light receiver. The method is experimentally

  8. Optimizing Lidar Scanning Strategies for Wind Energy Measurements (Invited)

    Science.gov (United States)

    Newman, J. F.; Bonin, T. A.; Klein, P.; Wharton, S.; Chilson, P. B.

    2013-12-01

    Environmental concerns and rising fossil fuel prices have prompted rapid development in the renewable energy sector. Wind energy, in particular, has become increasingly popular in the United States. However, the intermittency of available wind energy makes it difficult to integrate wind energy into the power grid. Thus, the expansion and successful implementation of wind energy requires accurate wind resource assessments and wind power forecasts. The actual power produced by a turbine is affected by the wind speeds and turbulence levels experienced across the turbine rotor disk. Because of the range of measurement heights required for wind power estimation, remote sensing devices (e.g., lidar) are ideally suited for these purposes. However, the volume averaging inherent in remote sensing technology produces turbulence estimates that are different from those estimated by a sonic anemometer mounted on a standard meteorological tower. In addition, most lidars intended for wind energy purposes utilize a standard Doppler beam-swinging or Velocity-Azimuth Display technique to estimate the three-dimensional wind vector. These scanning strategies are ideal for measuring mean wind speeds but are likely inadequate for measuring turbulence. In order to examine the impact of different lidar scanning strategies on turbulence measurements, a WindCube lidar, a scanning Halo lidar, and a scanning Galion lidar were deployed at the Southern Great Plains Atmospheric Radiation Measurement (ARM) site in Summer 2013. Existing instrumentation at the ARM site, including a 60-m meteorological tower and an additional scanning Halo lidar, were used in conjunction with the deployed lidars to evaluate several user-defined scanning strategies. For part of the experiment, all three scanning lidars were pointed at approximately the same point in space and a tri-Doppler analysis was completed to calculate the three-dimensional wind vector every 1 second. In another part of the experiment, one of

  9. Comparison of wind pressure measurements on Silsoe ...

    African Journals Online (AJOL)

    user

    and the over production of turbulent kinetic energy near the sharp edges. The various RANS ... can predict the general wind conditions around building reasonably well except those in the separation regions .... cable to a remote A/D converter.

  10. Comparison of wind pressure measurements on Silsoe ...

    African Journals Online (AJOL)

    International Journal of Engineering, Science and Technology ... from full-scale observation, wind-tunnel experiments and various CFD techniques ... The paper is the result of extensive research concentrated on analyzing the accuracy and ...

  11. Comparison of wind pressure measurements on Silsoe ...

    African Journals Online (AJOL)

    user

    turbulence models available widely and the state of the art techniques for the ... model, suitable for wind engineering applications, should be able to model the .... the Commonwealth Advisory Aeronautical Council (CAARC) building using vari-.

  12. Wind energy analysis system

    OpenAIRE

    2014-01-01

    M.Ing. (Electrical & Electronic Engineering) One of the most important steps to be taken before a site is to be selected for the extraction of wind energy is the analysis of the energy within the wind on that particular site. No wind energy analysis system exists for the measurement and analysis of wind power. This dissertation documents the design and development of a Wind Energy Analysis System (WEAS). Using a micro-controller based design in conjunction with sensors, WEAS measure, calcu...

  13. Rotor equivalent wind speed for power curve measurement – comparative exercise for IEA Wind Annex 32

    DEFF Research Database (Denmark)

    Wagner, Rozenn; Cañadillas, B.; Clifton, A.

    2014-01-01

    was the definition of the segment area used as weighting for the wind speeds measured at the various heights in the calculation of the REWS. This comparative exercise showed that the REWS method results in a significant difference compared to the standard method using the wind speed at hub height in conditions...

  14. Wind profile modelling using WAsP and "tall" wind measurements

    DEFF Research Database (Denmark)

    Floors, Rogier Ralph; Kelly, Mark C.; Troen, Ib

    2015-01-01

    extrapolations (the wind profile) this is done using the Weibull distribution and the geostrophic drag law. Wind lidar measurements obtained during the ’Tall wind’ campaign at three different sites are used to evaluate the assumptions and equations that are used in the WAsP vertical extrapolation strategy...

  15. Wake Measurements in ECN's Scaled Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Wagenaar, J.W.; Schepers, J.G. [ECN Wind Energy, Petten (Netherlands)

    2013-02-15

    In ECN's scaled wind farm the wake evolution is studied in two different situations. A single wake is studied at two different locations downstream of a turbine and a single wake is studied in conjunction with a triple wake. Here, the wake is characterized by the wind speed ratio, the turbulence intensity, the vertical wind speed and the turbulence (an)isotropy. Per situation all wake measurements are taken simultaneously together with the inflow conditions.

  16. Optimal sensor locations for the backward Lagrangian stochastic technique in measuring lagoon gas emission

    Science.gov (United States)

    This study evaluated the impact of gas concentration and wind sensor locations on the accuracy of the backward Lagrangian stochastic inverse-dispersion technique (bLS) for measuring gas emission rates from a typical lagoon environment. Path-integrated concentrations (PICs) and 3-dimensional (3D) wi...

  17. Wind Turbine Measurement Technique—an Open Laboratory for Educational Purposes

    DEFF Research Database (Denmark)

    Pedersen, Knud Ole Helgesen; Hansen, Kurt Schaldemose; Schmidt Paulsen, Uwe

    2008-01-01

    operational parameters, (ii) meteorological onditions, (iii) electrical quantities and (iv) mechanical loads. The data acquisition system was PC based, and it was combined with a MySQL® database for data management.The system enabled online access for real-time recordings,which were used both...... of non-commercial time series, which would be available for practicing fatigue calculations and extreme load estimation in basic wind turbine courses. Power quality analysis was carried out based on high-speed-sampled, three-phase voltage and current signals. The wide spectrum of sensors enabled....... The WTMLAB was included in a new course entitled Wind Turbine Measurement Techniques....

  18. Real-time Wind Profile Estimation using Airborne Sensors

    NARCIS (Netherlands)

    In 't Veld, A.C.; De Jong, P.M.A.; Van Paassen, M.M.; Mulder, M.

    2011-01-01

    Wind is one of the major contributors to uncertainty in continuous descent approach operations. Especially when aircraft that are flying low or idle thrust approaches are issued a required time of arrival over the runway threshold, as is foreseen in some of the future ATC scenarios, the on-board

  19. Multi-component wind measurements of wind turbine wakes performed with three LiDARs

    Science.gov (United States)

    Iungo, G. V.; Wu, Y.-T.; Porté-Agel, F.

    2012-04-01

    Field measurements of the wake flow produced from the interaction between atmospheric boundary layer and a wind turbine are performed with three wind LiDARs. The tested wind turbine is a 2 MW Enercon E-70 located in Collonges, Switzerland. First, accuracy of mean values and frequency resolution of the wind measurements are surveyed as a function of the number of laser rays emitted for each measurement. Indeed, measurements performed with one single ray allow maximizing sampling frequency, thus characterizing wake turbulence. On the other hand, if the number of emitted rays is increased accuracy of mean wind is increased due to the longer sampling period. Subsequently, two-dimensional measurements with a single LiDAR are carried out over vertical sections of the wind turbine wake and mean wake flow is obtained by averaging 2D measurements consecutively performed. The high spatial resolution of the used LiDAR allows characterizing in details velocity defect present in the central part of the wake and its downstream recovery. Single LiDAR measurements are also performed by staring the laser beam at fixed directions for a sampling period of about ten minutes and maximizing the sampling frequency in order to characterize wake turbulence. From these tests wind fluctuation peaks are detected in the wind turbine wake at blade top-tip height for different downstream locations. The magnitude of these turbulence peaks is generally reduced by moving downstream. This increased turbulence level at blade top-tip height observed for a real wind turbine has been already detected from previous wind tunnel tests and Large Eddy simulations, thus confirming the presence of a source of dangerous fatigue loads for following wind turbines within a wind farm. Furthermore, the proper characterization of wind fluctuations through LiDAR measurements is proved by the detection of the inertial subrange from spectral analysis of these velocity signals. Finally, simultaneous measurements with two

  20. Model Predictive Control of Wind Turbines using Uncertain LIDAR Measurements

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Soltani, Mohsen; Poulsen, Niels Kjølstad

    2013-01-01

    , we simplify state prediction for the MPC. Consequently, the control problem of the nonlinear system is simplified into a quadratic programming. We consider uncertainty in the wind propagation time, which is the traveling time of wind from the LIDAR measurement point to the rotor. An algorithm based......The problem of Model predictive control (MPC) of wind turbines using uncertain LIDAR (LIght Detection And Ranging) measurements is considered. A nonlinear dynamical model of the wind turbine is obtained. We linearize the obtained nonlinear model for different operating points, which are determined...... on wind speed estimation and measurements from the LIDAR is devised to find an estimate of the delay and compensate for it before it is used in the controller. Comparisons between the MPC with error compensation, the MPC without error compensation and an MPC with re-linearization at each sample point...

  1. Wind atlas for Egypt: Measurements, micro- and mesoscale modelling

    DEFF Research Database (Denmark)

    Mortensen, N.G.; Hansen, J.C.; Badger, J.

    2006-01-01

    – close to consumers and the electrical grid. The KAMM simulations seem to capture the main features of the wind climate of Egypt, but in regions where the horizontal wind gradients are large, the uncertainties are large as well and additional measurements are required. The results are now published...

  2. CAT LIDAR wind shear studies

    Science.gov (United States)

    Goff, R. W.

    1978-01-01

    The studies considered the major meteorological factors producing wind shear, methods to define and classify wind shear in terms significant from an aircraft perturbation standpoint, the significance of sensor location and scan geometry on the detection and measurement of wind shear, and the tradeoffs involved in sensor performance such as range/velocity resolution, update frequency and data averaging interval.

  3. GPS/INS Sensor Fusion Using GPS Wind up Model

    Science.gov (United States)

    Williamson, Walton R. (Inventor)

    2013-01-01

    A method of stabilizing an inertial navigation system (INS), includes the steps of: receiving data from an inertial navigation system; and receiving a finite number of carrier phase observables using at least one GPS receiver from a plurality of GPS satellites; calculating a phase wind up correction; correcting at least one of the finite number of carrier phase observables using the phase wind up correction; and calculating a corrected IMU attitude or velocity or position using the corrected at least one of the finite number of carrier phase observables; and performing a step selected from the steps consisting of recording, reporting, or providing the corrected IMU attitude or velocity or position to another process that uses the corrected IMU attitude or velocity or position. A GPS stabilized inertial navigation system apparatus is also described.

  4. Pressure field in measurement section of wind tunnel

    Directory of Open Access Journals (Sweden)

    Hnidka Jakub

    2017-01-01

    Full Text Available The University of Defence in Brno has a new low-speed wind tunnel. In order to confirm the quality of the wind inside of the measurement section, several measurements of the dynamic pressure have been performed with the Pitot-static tube. The pressure fields are then analysed and quality of the field is evaluated. Measurement of a pressure drop on the body of a standing helicopter was conducted.

  5. Inflow measurements from blade-mounted flow sensors: Flow analysis, application and aeroelastic response

    DEFF Research Database (Denmark)

    Pedersen, Mads Mølgaard

    -mounted flow sensor, BMFS, e.g. a five-hole pitot tube, which has been used in several research experiments over the last 30 years. The BMFS measured flow velocity is, however, located inside the induction zone and thereby influenced by the aerodynamic properties, the control strategy and the operational......The power and load performance of wind turbines are both crucial for the development and expansion of wind energy. The power and loads are highly dependent on the inflow conditions, which can be measured using different types of sensors mounted on nearby met masts, on the nacelle, at the spinner...... or at the blade. Each combination of sensor type and mounting position has advantages and shortcomings. To characterise the inflow that results in high and low fatigue loads, information about the temporal and spatial variations within the rotor area is required. This information can be obtained from a blade...

  6. Kinematic measurements using an infrared sensor

    International Nuclear Information System (INIS)

    Marinho, F; Paulucci, L

    2016-01-01

    The use of an infrared sensor as a new alternative to measure position as a function of time in kinematic experiments was investigated using a microcontroller as the data acquisition and control device. These are versatile sensors that offer advantages over typical ultrasound devices. The setup described in this paper enables students to develop their own experiments, promoting opportunities for learning physical concepts such as the different types of forces that can act on a body (gravitational, elastic, drag, etc) and the resulting types of movements with good sensitivity within the 4–30 cm range. As a proof of concept we also present the application of a prototype designed to record the kinematics of mass-spring systems. (paper)

  7. A sensor element for direct radiation measurement

    Energy Technology Data Exchange (ETDEWEB)

    Bajons, P.; Wernhart, U.; Zeiler, H. [University of Vienna (Austria). Institut of Material Physics

    1998-08-01

    A combination of a photodiode with a nonimaging light concentrator is developed to perform measurements of the direct solar radiation component. A prototype composed of low price elements is taken as a starting point to discuss the problems which must be faced when calibrating such sensors. By this the influence of the angle of incidence and spectral distribution (caused by different air mass or varying degree of clearness) of the incident radiation on the behavior of the system is studied. The readings are compared to the calculated (global minus diffuse) readings obtained from two standard star pyranometers. Finally the possibilities for increasing the accuracy of the sensor element and for applying the device are discussed. (author)

  8. Simulation of the Impact of New Aircraft- and Satellite-Based Ocean Surface Wind Measurements on H*Wind Analyses and Numerical Forecasts

    Science.gov (United States)

    Miller, Timothy; Atlas, Robert; Black, Peter; Chen, Shuyi; Hood, Robbie; Johnson, James; Jones, Linwood; Ruf, Chris; Uhlhorn, Eric; Krishnamurti, T. N.; hide

    2009-01-01

    The Hurricane Imaging Radiometer (HIRAD) is a new airborne microwave remote sensor for hurricane observations that is currently under development by NASA Marshall Space Flight Center, NOAA Hurricane Research Division, the University of Central Florida and the University of Michigan. HIRAD is being designed to enhance the realtime airborne ocean surface winds observation capabilities of NOAA and USAF Weather Squadron hurricane hunter aircraft using the operational airborne Stepped Frequency Microwave Radiometer (SFMR). Unlike SFMR, which measures wind speed and rain rate along the ground track directly beneath the aircraft, HIRAD will provide images of the surface wind and rain field over a wide swath ( 3 x the aircraft altitude). The present paper describes a set of Observing System Simulation Experiments (OSSEs) in which measurements from the new instrument as well as those from existing instruments (air, surface, and space-based) are simulated from the output of a detailed numerical model, and those results are used to construct H*Wind analyses. The H*Wind analysis, a product of the Hurricane Research Division of NOAA s Atlantic Oceanographic and Meteorological Laboratory, brings together wind measurements from a variety of observation platforms into an objective analysis of the distribution of wind speeds in a tropical cyclone. This product is designed to improve understanding of the extent and strength of the wind field, and to improve the assessment of hurricane intensity. See http://www.aoml.noaa.gov/hrd/data_sub/wind.html. Evaluations will be presented on the impact of the HIRAD instrument on H*Wind analyses, both in terms of adding it to the full suite of current measurements, as well as using it to replace instrument(s) that may not be functioning at the future time the HIRAD instrument is implemented. Also shown will be preliminary results of numerical weather prediction OSSEs in which the impact of the addition of HIRAD observations to the initial state

  9. Sensor for viscosity and shear strength measurement

    Energy Technology Data Exchange (ETDEWEB)

    Ebadian, M.A.; Dillion, J.; Moore, J.; Jones, K.

    1998-01-01

    Measurement of the physical properties (viscosity and density) of waste slurries is critical in evaluating transport parameters to ensure turbulent flow through transport pipes. The environment for measurement and sensor exposure is extremely harsh; therefore, reliability and ruggedness are critical in the sensor design. Two different viscometer techniques are being investigated in this study, based on: magnetostrictive pulse generated acoustic waves; and an oscillating cylinder. Prototype sensors have been built and tested which are based on both techniques. A base capability instrumentation system has been designed, constructed, and tested which incorporates both of these sensors. It requires manual data acquisition and off-line calculation. A broad range of viscous media has been tested using this system. Extensive test results appear in this report. The concept for each technique has been validated by these test results. This base capability system will need to be refined further before it is appropriate for field tests. The mass of the oscillating system structure will need to be reduced. A robust acoustic probe assembly will need to be developed. In addition, in March 1997 it was made known for the first time that the requirement was for a deliverable automated viscosity instrumentation system. Since then such a system has been designed, and the hardware has been constructed so that the automated concept can be proved. The rest of the hardware, which interfaced to a computer, has also been constructed and tested as far as possible. However, for both techniques the computer software for automated data acquisition, calculation, and logging had not been completed before funding and time ran out.

  10. Representativeness of wind measurements in moderately complex terrain

    Science.gov (United States)

    van den Bossche, Michael; De Wekker, Stephan F. J.

    2018-02-01

    We investigated the representativeness of 10-m wind measurements in a 4 km × 2 km area of modest relief by comparing observations at a central site with those at four satellite sites located in the same area. Using a combination of established and new methods to quantify and visualize representativeness, we found significant differences in wind speed and direction between the four satellite sites and the central site. The representativeness of the central site wind measurements depended strongly on surface wind speed and direction, and atmospheric stability. Through closer inspection of the observations at one of the satellite sites, we concluded that terrain-forced flows combined with thermally driven downslope winds caused large biases in wind direction and speed. We used these biases to generate a basic model, showing that terrain-related differences in wind observations can to a large extent be predicted. Such a model is a cost-effective way to enhance an area's wind field determination and to improve the outcome of pollutant dispersion and weather forecasting models.

  11. Kompensasi Kesalahan Sensor Berbasis Descriptor dengan Performa H_inf pada Winding Machine

    Directory of Open Access Journals (Sweden)

    Hendra Antomy

    2015-12-01

    Full Text Available Kesalahan pada sensor dapat terjadi pada sistem kontrol dengan umpan balik sehingga mengakibatkan sistem mengalami penurunan stabilitas dan performa. Fault Tolerant Control (FTC adalah metode untuk mengkompensasi kesalahan pada komponen sistem, salah satunya adalah kesalahan sensor. FTC dapat disusun dengan cara mendesain estimator untuk mengestimasi besarnya kesalahan sensor yang terjadi. Kompensasi dilakukan dengan cara mengurangkan estimasi kesalahan sensor dengan keluaran sistem. Pada makalah ini, FTC untuk kesalahan sensor diterapkan pada sistem winding machine. Estimator dirancang menggunakan pendekatan sistem descriptor dan didesain memenuhi performa H_inf. Permasalahan dalam desain estimator dirumuskan dalam bentuk Linear Matrix Inequality (LMI. Untuk merancang kontroler nominal, sistem winding machine direpresentasikan sebagai model fuzzy Takagi-Sugeno (T-S. Berdasarkan model tersebut, aturan kontroler disusun menggunakan konsep Parallel Distributed Compensation (PDC dengan struktur kontrol servo tipe 1. Hasil simulasi menunjukkan bahwa kompensasi yang diberikan dapat menjaga performa dan stabilitas sistem saat terjadi kesalahan sensor. Selain itu, estimator memenuhi performa H_inf dengan L2-Gain kurang dari tingkat pelemahan yang ditentukan.

  12. Wind measurement on the Linth plain; Windmessung in der Linthebene

    Energy Technology Data Exchange (ETDEWEB)

    Langraf, B.

    2003-07-01

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) presents the results of wind measurements made on the Linth plain, a flat alluvial plain in eastern Switzerland located between mountain ranges. The data, which were collected using temporary measurement masts at two locations are presented in the form of tables, diagrams and maps showing the wind-energy potential of various areas of the plain. The actual measurements are compared with prognoses from a geo-information system. The wind measurement equipment and installations are described, as are the software models for the calculation of wind direction, wind intensity and of a prognosis for energy production. Particular attention was also paid to the question of wind turbulence. Further factors investigated included the possibility of icing-up in winter and the choice of a meteorological station in the neighbourhood with similar characteristics that could be used as a reference station. The report also presents the results of the evaluation of various possible locations for wind turbines on the Linth plain. Visual, noise and shadow-casing factors are considered.

  13. High-altitude wind prediction and measurement technology assessment

    Science.gov (United States)

    2009-06-30

    The principles and operational characteristics of balloon and radar-based techniques for measuring upper air winds in support of launches and recoveries are presented. Though either a balloon or radar system could serve as a standalone system, the sa...

  14. Wind Ressources in Complex Terrain investigated with Synchronized Lidar Measurements

    Science.gov (United States)

    Mann, J.; Menke, R.; Vasiljevic, N.

    2017-12-01

    The Perdigao experiment was performed by a number of European and American universities in Portugal 2017, and it is probably the largest field campaign focussing on wind energy ressources in complex terrain ever conducted. 186 sonic anemometers on 50 masts, 20 scanning wind lidars and a host of other instruments were deployed. The experiment is a part of an effort to make a new European wind atlas. In this presentation we investigate whether scanning the wind speed over ridges in this complex terrain with multiple Doppler lidars can lead to an efficient mapping of the wind resources at relevant positions. We do that by having pairs of Doppler lidars scanning 80 m above the ridges in Perdigao. We compare wind resources obtained from the lidars and from the mast-mounted sonic anemometers at 80 m on two 100 m masts, one on each of the two ridges. In addition, the scanning lidar measurements are also compared to profiling lidars on the ridges. We take into account the fact that the profiling lidars may be biased due to the curvature of the streamlines over the instrument, see Bingol et al, Meteorolog. Z. vol. 18, pp. 189-195 (2009). We also investigate the impact of interruptions of the lidar measurements on the estimated wind resource. We calculate the relative differences of wind along the ridge from the lidar measurements and compare those to the same obtained from various micro-scale models. A particular subject investigated is how stability affects the wind resources. We often observe internal gravity waves with the scanning lidars during the night and we quantify how these affect the relative wind speed on the ridges.

  15. A New Position Measurement System Using a Motion-Capture Camera for Wind Tunnel Tests

    Directory of Open Access Journals (Sweden)

    Yousok Kim

    2013-09-01

    Full Text Available Considering the characteristics of wind tunnel tests, a position measurement system that can minimize the effects on the flow of simulated wind must be established. In this study, a motion-capture camera was used to measure the displacement responses of structures in a wind tunnel test, and the applicability of the system was tested. A motion-capture system (MCS could output 3D coordinates using two-dimensional image coordinates obtained from the camera. Furthermore, this remote sensing system had some flexibility regarding lab installation because of its ability to measure at relatively long distances from the target structures. In this study, we performed wind tunnel tests on a pylon specimen and compared the measured responses of the MCS with the displacements measured with a laser displacement sensor (LDS. The results of the comparison revealed that the time-history displacement measurements from the MCS slightly exceeded those of the LDS. In addition, we confirmed the measuring reliability of the MCS by identifying the dynamic properties (natural frequency, damping ratio, and mode shape of the test specimen using system identification methods (frequency domain decomposition, FDD. By comparing the mode shape obtained using the aforementioned methods with that obtained using the LDS, we also confirmed that the MCS could construct a more accurate mode shape (bending-deflection mode shape with the 3D measurements.

  16. Comparison of 3D turbulence measurements using three staring wind lidars and a sonic anemometer

    International Nuclear Information System (INIS)

    Mann, J; Courtney, M S; Mikkelsen, T; Wagner, R; Lindeloew, P; Sjoeholm, M; Enevoldsen, K; Cariou, J-P; Parmentier, R

    2008-01-01

    Three pulsed lidars were used in staring, non-scanning mode, placed so that their beams crossed close to a 3D sonic anemometer. The goal is to compare lidar volume averaged wind measurement with point measurement reference sensors and to demonstrate the feasibility of performing 3D turbulence measurements with lidars. The results show a very good correlation between the lidar and the sonic times series. The variance of the velocity measured by the lidar is attenuated due to spatial filtering, and the amount of attenuation can be predicted theoretically

  17. Empirical wind retrieval model based on SAR spectrum measurements

    Science.gov (United States)

    Panfilova, Maria; Karaev, Vladimir; Balandina, Galina; Kanevsky, Mikhail; Portabella, Marcos; Stoffelen, Ad

    The present paper considers polarimetric SAR wind vector applications. Remote-sensing measurements of the near-surface wind over the ocean are of great importance for the understanding of atmosphere-ocean interaction. In recent years investigations for wind vector retrieval using Synthetic Aperture Radar (SAR) data have been performed. In contrast with scatterometers, a SAR has a finer spatial resolution that makes it a more suitable microwave instrument to explore wind conditions in the marginal ice zones, coastal regions and lakes. The wind speed retrieval procedure from scatterometer data matches the measured radar backscattering signal with the geophysical model function (GMF). The GMF determines the radar cross section dependence on the wind speed and direction with respect to the azimuthal angle of the radar beam. Scatterometers provide information on wind speed and direction simultaneously due to the fact that each wind vector cell (WVC) is observed at several azimuth angles. However, SAR is not designed to be used as a high resolution scatterometer. In this case, each WVC is observed at only one single azimuth angle. That is why for wind vector determination additional information such as wind streak orientation over the sea surface is required. It is shown that the wind vector can be obtained using polarimetric SAR without additional information. The main idea is to analyze the spectrum of a homogeneous SAR image area instead of the backscattering normalized radar cross section. Preliminary numerical simulations revealed that SAR image spectral maxima positions depend on the wind vector. Thus the following method for wind speed retrieval is proposed. In the first stage of the algorithm, the SAR spectrum maxima are determined. This procedure is carried out to estimate the wind speed and direction with ambiguities separated by 180 degrees due to the SAR spectrum symmetry. The second stage of the algorithm allows us to select the correct wind direction

  18. Noise measurement on Preshower Si sensors

    CERN Document Server

    Evangelou, Ioannis; Barney, David; Bloch, Philippe; Elsha, Vladimir; Go, Apollo; Kloukinas, Kostas; Kokkas, Panagiotis; Manthos, Nikolaos; Peisert, Anna; Prouskas, C; Reynaud, Serge; Triantis, Frixos A; Tzoulis, Nikolaos; Zub, E

    2002-01-01

    Throughout the past couple of years when we were designing the Preshower silicon sensors we have noticed that some of them have strips with a noise higher than the average and not correlated to the leakage current. In order to investigate this effect we have developed a set-up for noise measurement on wafers and diced sensors that does not require bonding. The set-up is based on the DeltaStream chip coupled to a probe card with 32 pins at a pitch of 1.9 mm. All the digital electronics, including the analogue-to-digital converter and a microprocessor, is placed on a motherboard which communicates with a PC via an RS232 line. We have tested 45 sensors and found that some strips which have an above average noise, also have a higher relative current increase as a function of voltage, deltaI/(I deltaV), even though their leakage current is below 50 nA. We also observed that on these strips th e breakdown occurs within about 60 V from the onset of the noise. The source of this noise is not yet clear and the investi...

  19. Fluxgate Magnetic Sensor and Its Application for Current Measurement

    International Nuclear Information System (INIS)

    Mitra-Djamal

    2007-01-01

    Conventionally electric current can be measured by connecting the instrument serially on the circuit. This method has disadvantage because its disturb the measured current flow. By using a magnetic sensor, current can be measured without disturbing the current flow, because it just measures the magnetic field of the measured current. This paper shows the use of fluxgate magnetic sensor for current measurement. It is shown that the sensor can measure widely range of current with resolution ≤ 2 %. (author)

  20. Electrostatic sensor modeling for torque measurements

    Directory of Open Access Journals (Sweden)

    M. Mika

    2017-09-01

    Full Text Available Torque load measurements play an important part in various engineering applications, as for automotive industry, in which the drive torque of a motor has to be determined. A widely used measuring method are strain gauges. A thin flexible foil, which supports a metallic pattern, is glued to the surface of the object the torque is being applied to. In case of a deformation due to the torque load, the change in the electrical resistance is measured. With the combination of constitutive equations the applied torque load is determined by the change of electrical resistance. The creep of the glue and the foil material, together with the temperature and humidity dependence, may become an obstacle for some applications Kapralov and Fesenko(1984. Thus, there have been optical and magnetical, as well as capacitive sensors introduced . This paper discusses the general idea behind an electrostatic capacitive sensor based on a simple draft of an exemplary measurement setup. For better understanding an own electrostatical, geometrical and mechanical model of this setup has been developed.

  1. Electrostatic sensor modeling for torque measurements

    Science.gov (United States)

    Mika, Michał; Dannert, Mirjam; Mett, Felix; Weber, Harry; Mathis, Wolfgang; Nackenhorst, Udo

    2017-09-01

    Torque load measurements play an important part in various engineering applications, as for automotive industry, in which the drive torque of a motor has to be determined. A widely used measuring method are strain gauges. A thin flexible foil, which supports a metallic pattern, is glued to the surface of the object the torque is being applied to. In case of a deformation due to the torque load, the change in the electrical resistance is measured. With the combination of constitutive equations the applied torque load is determined by the change of electrical resistance. The creep of the glue and the foil material, together with the temperature and humidity dependence, may become an obstacle for some applications Kapralov and Fesenko (1984). Thus, there have been optical and magnetical, as well as capacitive sensors introduced). This paper discusses the general idea behind an electrostatic capacitive sensor based on a simple draft of an exemplary measurement setup. For better understanding an own electrostatical, geometrical and mechanical model of this setup has been developed.

  2. Optical measurements of winds in the lower thermosphere

    International Nuclear Information System (INIS)

    Wiens, R.H.; Shepherd, G.G.; Gault, W.A.; Kosteniuk, P.R.

    1988-01-01

    WAMDII, the wide-angle Michelson Doppler imaging interferometer, was used to measure the neutral wind in the lower thermosphere by the Doppler shift of the O I 557-nm line. Observations were made at Saskatoon (60.5 degree N invariant) around the spring equinox of 1985 with WAMDII coupled to an all-sky lens. With dopplergrams averaged over 3 to 30 min, no evidence was found for persistent highly localized winds on either of the two nights studied, one viewing only aurora and one viewing only airglow. The nocturnal variation was determined for both nights using average horizontal wind for the whole all-sky image. The pattern for the auroral case shows winds parallel to the aurora orientation in the evening but substantial crosswinds near midnight. High latitude general circulation models seem to represent this case better than local auroral generation models. The airglow case showed eastward winds in the morning sector

  3. Velocity measurement of model vertical axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.A.; McWilliam, M. [Waterloo Univ., ON (Canada). Dept. of Mechanical Engineering

    2006-07-01

    An increasingly popular solution to future energy demand is wind energy. Wind turbine designs can be grouped according to their axis of rotation, either horizontal or vertical. Horizontal axis wind turbines have higher power output in a good wind regime than vertical axis turbines and are used in most commercial class designs. Vertical axis Savonius-based wind turbine designs are still widely used in some applications because of their simplistic design and low wind speed performance. There are many design variables that must be considered in order to optimize the power output in a given wind regime in a typical wind turbine design. Using particle image velocimetry, a study of the air flow around five different model vertical axis wind turbines was conducted in a closed loop wind tunnel. A standard Savonius design with two semi-circular blades overlapping, and two variations of this design, a deep blade and a shallow blade design were among the turbine models included in this study. It also evaluated alternate designs that attempt to increase the performance of the standard design by allowing compound blade curvature. Measurements were collected at a constant phase angle and also at random rotor orientations. It was found that evaluation of the flow patterns and measured velocities revealed consistent and stable flow patterns at any given phase angle. Large scale flow structures are evident in all designs such as vortices shed from blade surfaces. An important performance parameter was considered to be the ability of the flow to remain attached to the forward blade and redirect and reorient the flow to the following blade. 6 refs., 18 figs.

  4. Empowering smartphone users with sensor node for air quality measurement

    Science.gov (United States)

    Oletic, Dinko; Bilas, Vedran

    2013-06-01

    We present an architecture of a sensor node developed for use with smartphones for participatory sensing of air quality in urban environments. Our solution features inexpensive metal-oxide semiconductor gas sensors (MOX) for measurement of CO, O3, NO2 and VOC, along with sensors for ambient temperature and humidity. We focus on our design of sensor interface consisting of power-regulated heater temperature control, and the design of resistance sensing circuit. Accuracy of the sensor interface is characterized. Power consumption of the sensor node is analysed. Preliminary data obtained from the CO gas sensors in laboratory conditions and during the outdoor field-test is shown.

  5. Empowering smartphone users with sensor node for air quality measurement

    International Nuclear Information System (INIS)

    Oletic, Dinko; Bilas, Vedran

    2013-01-01

    We present an architecture of a sensor node developed for use with smartphones for participatory sensing of air quality in urban environments. Our solution features inexpensive metal-oxide semiconductor gas sensors (MOX) for measurement of CO, O 3 , NO 2 and VOC, along with sensors for ambient temperature and humidity. We focus on our design of sensor interface consisting of power-regulated heater temperature control, and the design of resistance sensing circuit. Accuracy of the sensor interface is characterized. Power consumption of the sensor node is analysed. Preliminary data obtained from the CO gas sensors in laboratory conditions and during the outdoor field-test is shown.

  6. Phasor measurement of wind power plant operation in Eastern Denmark

    DEFF Research Database (Denmark)

    Rasmussen, Joana; Nielsen, Arne Hejde

    2007-01-01

    Four Phasor Measurement Units (PMUs) record continuously voltage and current phasors in the 400 kV and 132 kV transmission system of Eastern Denmark. The abstract evaluates the unique concept for power system monitoring using PMUs. It focuses on utilization of synchronized phasor measurements from...... Nysted off-shore wind farm during a severe storm in 2005. The wind speeds during the event were so high, that Nysted offshore wind farm as well as a significant amount of on-land wind production in Denmark was disconnected from the grid. The PMU analysis illustrates that PMUs complement the traditional...... measurements from a traditional SCADA system. The case reveals the close relation between voltages, power flows and voltage phase angles over a wide area....

  7. Comet 73P Measurements of Solar Wind Interactions, Cometary Ion Pickup, and Spatial Distribution

    Science.gov (United States)

    Gilbert, J. A.; Lepri, S. T.; Rubin, M.; Combi, M. R.; Zurbuchen, T.

    2015-12-01

    Several fragments of Comet 73P/Schwassmann-Wachmann 3 passed near the Earth following a 2006 disintegration episode. Unique measurements regarding the charge state composition and the elemental abundances of both cometary and heliospheric plasma were made during this time by both the ACE/SWICS and Wind/STICS sensors. As the solar wind passed through the neutral cometary coma, it experienced charge exchange that was observed as an increase in the ratio of He+/He++. In addition, particles originating from fragments trailing the major cometary objects were ionized and picked up by the solar wind. The cometary material can be identified by the concentrations of water-group pickup ions having a mass-per-charge ratio of 16-18 amu/e, indicating that these are actively sublimating fragments. Here we present an analysis of cometary composition, spatial distribution, directionality, and heliospheric interactions with a focus on Helium, Carbon (C/O), and water-group ions.

  8. Fundamentals for remote structural health monitoring of wind turbine blades - a preproject. Annex A. Cost-benefit for embedded sensors in large wind turbine blades

    OpenAIRE

    Hansen, L.G.; Lading, Lars

    2002-01-01

    This report contains the results of a cost-benefit analysis for the use of embed-ded sensors for damage detection in large wind turbine blades - structural health monitoring - (in connection with remote surveillance) of large wind turbine placedoff-shore. The total operating costs of a three-bladed 2MW turbine placed offshore either without sensors or with sensors are compared. The price of a structural health monitoring system of a price of 100 000 DKK (per tur-bine) results in a break-event...

  9. "Rapid Revisit" Measurements of Sea Surface Winds Using CYGNSS

    Science.gov (United States)

    Park, J.; Johnson, J. T.

    2017-12-01

    The Cyclone Global Navigation Satellite System (CYGNSS) is a space-borne GNSS-R (GNSS-Reflectometry) mission that launched December 15, 2016 for ocean surface wind speed measurements. CYGNSS includes 8 small satellites in the same LEO orbit, so that the mission provides wind speed products having unprecedented coverage both in time and space to study multi-temporal behaviors of oceanic winds. The nature of CYGNSS coverage results in some locations on Earth experiencing multiple wind speed measurements within a short period of time (a "clump" of observations in time resulting in a "rapid revisit" series of measurements). Such observations could seemingly provide indications of regions experiencing rapid changes in wind speeds, and therefore be of scientific utility. Temporally "clumped" properties of CYGNSS measurements are investigated using early CYGNSS L1/L2 measurements, and the results show that clump durations and spacing vary with latitude. For example, the duration of a clump can extend as long as a few hours at higher latitudes, with gaps between clumps ranging from 6 to as high as 12 hours depending on latitude. Examples are provided to indicate the potential of changes within a clump to produce a "rapid revisit" product for detecting convective activity. Also, we investigate detector design for identifying convective activities. Results from analyses using recent CYGNSS L2 winds will be provided in the presentation.

  10. Evolution of offshore wind waves tracked by surface drifters with a point-positioning GPS sensor

    Science.gov (United States)

    Komatsu, K.

    2009-12-01

    Wind-generated waves have been recognized as one of the most important factors of the sea surface roughness which plays crucial roles in various air-sea interactions such as energy, momentum, heat and gas exchanges. At the same time, wind waves with extreme wave heights representatively called as freak or rogue waves have been a matter of great concern for many people involved in shipping, fishing, constracting, surfing and other marine activities, because such extreme waves frequently affect on the marine activities and sometimes cause serious disasters. Nevertheless, investigations of actual conditions for the evolution of wind waves in the offshore region are less and sparse in contrast to dense monitoring networks in the coastal regions because of difficulty of offshore observation with high accuracy. Recently accurate in situ observation of offshore wind waves is getting possible at low cost owing to a wave height and direction sensor developed by Harigae et al. (2004) by installing a point-positioning GPS receiver on a surface drifting buoy. The point-positioning GPS sensor can extract three dimensional movements of the buoy excited by ocean waves with minimizing effects of GPS point-positioning errors through the use of a high-pass filter. Two drifting buoys equipped with the GPS-based wave sensor charged by solar cells were drifted in the western North Pacific and one of them continued to observe wind waves during 16 months from Sep. 2007. The RMSE of the GPS-based wave sensor was less than 10cm in significant wave height and about 1s in significant wave period in comparison with other sensors, i.e. accelerometers installed on drifting buoys of Japan Meteorological Agency, ultrasonic sensors placed at the Hiratsuka observation station of the University of Tokyo and altimeter of the JASON-1. The GPS-based wave buoys enabled us to detect freak waves defined as waves whose height is more than twice the significant wave height. The observation conducted by the

  11. ACCUWIND - Accurate wind speed measurements in wind energy - Summary report[Cup and sonic anemometers

    Energy Technology Data Exchange (ETDEWEB)

    Friis Pedersen, T.; Dahlberg, J.Aa.; Cuerva, A.; Mouzakis, F.; Busche, P.; Eecen, P.; Sanz-Andres, A.; Franchini, S.; Markkilde Petersen, S.

    2006-07-15

    The cup anemometer is at present the standard instrument used for mean wind speed measurement in wind energy. It is being applied in high numbers around the world for wind energy assessments. It is also applied exclusively for accredited power performance measurements for certification and verification purposes, and for purposes of optimisation in research and development. The revised IEC standard on power performance measurements has now included requirements for classification of cup anemometers. The basis for setting up such requirements of cup anemometers is two EU projects SITEPARIDEN and CLASSCUP from which the proposed classification method for cup anemometers was developed for the IEC standard. While cup anemometers at present are the standard anemometer being used for average wind speed measurements, sonic anemometers have been developed significantly over the last years, and prices have come down. The application of sonic anemometers may increase in wind energy if they prove to have comparable or better operational characteristics compared to cup anemometers, and if similar requirements to sonic anemometers are established as for cup anemometers. Sonic anemometers have historically been used by meteorologists for turbulence measurements, but have also found a role on wind turbine nacelles for wind speed and yaw control purposes. The report on cup and sonic anemometry deals with establishment of robustness in assessment and classification by focus on methods and procedures for analysis of characteristics of cup and sonic anemometers. The methods and procedures provide a platform, hopefully for use in meeting the requirements of the IEC standard on power performance measurements, as well as for development of improved instruments. (au)

  12. Optical sensors for the measurement of electric current and voltage

    Energy Technology Data Exchange (ETDEWEB)

    Rutgers, W R; Hulshof, H J.M.; Laurensse, I J; van der Wey, A H

    1987-01-01

    Optical sensors for the measurement of electrical current and voltage were developed for application in electric power systems. The current sensor, based on the Faraday effect in a monomode glass fiber, and the voltage sensor, based on the transverse Pockels effect in a crystal, are demonstrated in wide-band (10 MHz) interference-free measurements of pulsed currents and impulse voltages.

  13. The sound power measurement and certification of wind turbines

    International Nuclear Information System (INIS)

    MacKinnon, A.; Henderson, R.

    1992-01-01

    It is anticipated that there will be a substantial growth in the exploitation of renewable energy from the wind over the next few years. A major factor in this expected growth is the environmental acceptance or otherwise of wind turbines and in particular their acoustic characteristics. It is generally accepted within the turbine community that reliable methods of measuring and quantifying a turbine's acoustic signature are essential if this exploitation is to be realised. This paper will seek to review current practice both in the UK and further afield and will describe the development of a practical and reliable test method, which will aid the wind turbine Manufacturer, Developer and Planner. (author)

  14. Cup anemometer response to the wind turbulence-measurement of the horizontal wind variance

    Directory of Open Access Journals (Sweden)

    S. Yahaya

    2004-11-01

    Full Text Available This paper presents some dynamic characteristics of an opto-electronic cup anemometer model in relation to its response to the wind turbulence. It is based on experimental data of the natural wind turbulence measured both by an ultrasonic anemometer and two samples of the mentioned cup anemometer. The distance constants of the latter devices measured in a wind tunnel are in good agreement with those determined by the spectral analysis method proposed in this study. In addition, the study shows that the linear compensation of the cup anemometer response, beyond the cutoff frequency, is limited to a given frequency, characteristic of the device. Beyond this frequency, the compensation effectiveness relies mainly on the wind characteristics, particularly the direction variability and the horizontal turbulence intensity. Finally, this study demonstrates the potential of fast cup anemometers to measure some turbulence parameters (like wind variance with errors of the magnitude as those deriving from the mean speed measurements. This result proves that fast cup anemometers can be used to assess some turbulence parameters, especially for long-term measurements in severe climate conditions (icing, snowing or sandy storm weathers.

  15. Development and Design of a Flexible Measurement System for Offshore Wind Farm

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Arana Aristi, Iván; Hjerrild, Jesper

    The development process of a flexible measurement system for multi-point, high-speed and long-term offshore data logging is described in this paper. This covers the complete design taking into account precise synchronisation, electromagnetic compatibility, software development and sensor...... calibration. The presented measurement set-up was tested in a rough offshore environment. Results from measurement campaigns at Avedøre and Gunfleet Sands offshore wind farms including synchronisation precision and accuracy, electromagnetic interference of power electronic devices are briefly presented....

  16. Development and Design of a Flexible Measurement System for Offshore Wind Farms

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Arana Aristi, Ivan; Hjerrild, Jesper

    2011-01-01

    The development process of a flexible measurement system for multi-point, high-speed and long-term offshore data logging is described in this paper. This covers the complete design taking into account precise synchronisation, electromagnetic compatibility, software development and sensor...... calibration. The presented measurement set-up was tested in a rough offshore environment. Results from measurement campaigns at Avedøre and Gunfleet Sands offshore wind farms including synchronisation precision and accuracy, electromagnetic interference of power electronic devices are briefly presented....

  17. Review of SQUID Sensors for Measuring Magnetocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. H.; Kim, J. M.; Yu, K. K.; Kim, K.; Kwon, H. [Brain and Cognition Measurement Lab, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2011-08-15

    Measurement of magnetic signals generated from electric activity of myocardium provides useful information for the functional diagnosis of heart diseases. Key technical component of the magnetocardiography (MCG) technology is SQUID. To measure MCG signals with high signal-to-noise ratio, sensitive SQUID magnetic field sensors are needed. Present magnetic field sensors based on Nb SQUIDs have field sensitivity good enough to measure most of MCG signals. However, for accurate measurement of fine signal pattern or detection of local atrial fibrillation signals, we may need higher field sensitivity. In addition to field sensitivity, economic aspect of the SQUID system is also important. To simplify the SQUID readout electronics, the output voltage or flux-to-voltage transfer of SQUID should be large enough so that direct measurement of SQUID output can be done using room-temperature preamplifiers. Double relaxation oscillation SQUID (DROS), having about 10 times larger flux-to-voltage transfers than those of DC-SQUIDs, was shown to be a good choice to make the electronics compact. For effective cancellation of external noise inside a thin economic shielded room, first-order axial gradiometer with high balance, simple structure and long-baseline is needed. We developed a technology to make the axial gradiometer compact using direct bonding of superconductive wires between pickup coil and input coil. Conventional insert has mechanical support to hold the gradiometer array, and the dewar neck has equal diameter with the dewar bottom. Boiling of the liquid He can generate mechanical vibrations in the gradiometer array due to mechanical connection structure. Elimination of the mechanical support, and direct mounting of the gradiometer array into the dewar bottom can reduce the dewar neck diameter, resulting in the reduction of liquid He consumption.

  18. Noise measurement at wind power plants; Geraeuschmessung an Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Schoene, Ralph [Cirrus Research plc, Frankfurt am Main (Germany)

    2012-09-15

    Wind energy is a supporting pillar of the energy transition. For further expansion, it is important to reduce prejudices, for example by measurements as precise as possible and assessments of the often unobjectively discussed noise emissions. These measurements are based on instruments which can analyze and measure low-frequency sound.

  19. Underwater Acoustic Measurements to Estimate Wind and Rainfall in the Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Sara Pensieri

    2015-01-01

    Full Text Available Oceanic ambient noise measurements can be analyzed to obtain qualitative and quantitative information about wind and rainfall phenomena over the ocean filling the existing gap of reliable meteorological observations at sea. The Ligurian Sea Acoustic Experiment was designed to collect long-term synergistic observations from a passive acoustic recorder and surface sensors (i.e., buoy mounted rain gauge and anemometer and weather radar to support error analysis of rainfall rate and wind speed quantification techniques developed in past studies. The study period included combination of high and low wind and rainfall episodes and two storm events that caused two floods in the vicinity of La Spezia and in the city of Genoa in 2011. The availability of high resolution in situ meteorological data allows improving data processing technique to detect and especially to provide effective estimates of wind and rainfall at sea. Results show a very good correspondence between estimates provided by passive acoustic recorder algorithm and in situ observations for both rainfall and wind phenomena and demonstrate the potential of using measurements provided by passive acoustic instruments in open sea for early warning of approaching coastal storms, which for the Mediterranean coastal areas constitutes one of the main causes of recurrent floods.

  20. Development of Rayleigh Doppler lidar for measuring middle atmosphere winds

    Science.gov (United States)

    Raghunath, K.; Patra, A. K.; Narayana Rao, D.

    Interpretation of most of the middle and upper atmospheric dynamical and chemical data relies on the climatological description of the wind field Rayleigh Doppler lidar is one instrument which monitors wind profiles continuously though continuity is limited to clear meteorological conditions in the middle atmosphere A Doppler wind lidar operating in incoherent mode gives excellent wind and temperature information at these altitudes with necessary spectral sensitivity It observes atmospheric winds by measuring the spectral shift of the scattered light due to the motions of atmospheric molecules with background winds and temperature by spectral broadening The presentation is about the design and development of Incoherent Doppler lidar to obtain wind information in the height regions of 30-65 km The paper analyses and describes various types of techniques that can be adopted viz Edge technique and Fringe Imaging technique The paper brings out the scientific objectives configuration simulations error sources and technical challenges involved in the development of Rayleigh Doppler lidar The presentation also gives a novel technique for calibrating the lidar

  1. Demonstration of an efficient interpolation technique of inverse time and distance for Oceansat-2 wind measurements at 6-hourly intervals

    Directory of Open Access Journals (Sweden)

    J Swain

    2017-12-01

    Full Text Available Indian Space Research Organization had launched Oceansat-2 on 23 September 2009, and the scatterometer onboard was a space-borne sensor capable of providing ocean surface winds (both speed and direction over the globe for a mission life of 5 years. The observations of ocean surface winds from such a space-borne sensor are the potential source of data covering the global oceans and useful for driving the state-of-the-art numerical models for simulating ocean state if assimilated/blended with weather prediction model products. In this study, an efficient interpolation technique of inverse distance and time is demonstrated using the Oceansat-2 wind measurements alone for a selected month of June 2010 to generate gridded outputs. As the data are available only along the satellite tracks and there are obvious data gaps due to various other reasons, Oceansat-2 winds were subjected to spatio-temporal interpolation, and 6-hour global wind fields for the global oceans were generated over 1 × 1 degree grid resolution. Such interpolated wind fields can be used to drive the state-of-the-art numerical models to predict/hindcast ocean-state so as to experiment and test the utility/performance of satellite measurements alone in the absence of blended fields. The technique can be tested for other satellites, which provide wind speed as well as direction data. However, the accuracy of input winds is obviously expected to have a perceptible influence on the predicted ocean-state parameters. Here, some attempts are also made to compare the interpolated Oceansat-2 winds with available buoy measurements and it was found that they are reasonably in good agreement with a correlation coefficient of R  > 0.8 and mean deviation 1.04 m/s and 25° for wind speed and direction, respectively.

  2. Assessing trophic linkages in and around offshore wind farms using two high-speed optical sensors

    Science.gov (United States)

    Dudeck, Tim; Hufnagl, Marc; Auch, Dominik; Eckhardt, André; Möller, Klas-Ove; van Beusekom, Justus; Walter, Bettina; Möllmann, Christian; Floeter, Jens

    2016-04-01

    In search for clean, renewable energy sources European countries have built and planned numerous Offshore Wind Farms (OWF) in the North Sea region. While some research has been carried out on their influence on marine mammals and bottom-dwelling organisms, less is known about fish and lower trophic levels in these areas. Yet, marine mammals purposely seek these structures and there are indications that there are higher chances of fish encounters. However, the local bottom-up effects probably driving these aggregations of higher trophic level organisms are poorly understood. In this study we show preliminary results of primary and secondary production in and around German OWFs in the North Sea using a Laser Optical Particle Counter and a Video Plankton Recorder. With the two sensors working simultaneously on the TRIAXUS system at high speed, we were able to investigate and ground-truth size-spectrum changes on a very high spatial resolution making it possible to detect OWF effects from local to larger scales. Our results show new possibilities in OWF research and the necessity to collect highly resolved field data for meaningful results in these dynamic environments. Furthermore, the use of size spectra simplifies the integration of energy flow through low and medium trophic levels into biogeochemical models by using only a single automatically measurable variable such as size.

  3. Flight and wind-tunnel calibrations of a flush airdata sensor at high angles of attack and sideslip and at supersonic Mach numbers

    Science.gov (United States)

    Moes, Timothy R.; Whitmore, Stephen A.; Jordan, Frank L., Jr.

    1993-01-01

    A nonintrusive airdata-sensing system was calibrated in flight and wind-tunnel experiments to an angle of attack of 70 deg and to angles of sideslip of +/- 15 deg. Flight-calibration data have also been obtained to Mach 1.2. The sensor, known as the flush airdata sensor, was installed on the nosecap of an F-18 aircraft for flight tests and on a full-scale F-18 forebody for wind-tunnel tests. Flight tests occurred at the NASA Dryden Flight Research Facility, Edwards, California, using the F-18 High Alpha Research Vehicle. Wind-tunnel tests were conducted in the 30- by 60-ft wind tunnel at the NASA LaRC, Hampton, Virginia. The sensor consisted of 23 flush-mounted pressure ports arranged in concentric circles and located within 1.75 in. of the tip of the nosecap. An overdetermined mathematical model was used to relate the pressure measurements to the local airdata quantities. The mathematical model was based on potential flow over a sphere and was empirically adjusted based on flight and wind-tunnel data. For quasi-steady maneuvering, the mathematical model worked well throughout the subsonic, transonic, and low supersonic flight regimes. The model also worked well throughout the angle-of-attack and sideslip regions studied.

  4. Performance enhancement and load reduction on wind turbines using inflow measurements

    Energy Technology Data Exchange (ETDEWEB)

    Abildgaard Kragh, K.

    2013-06-15

    Wind energy is being applied at a larger and larger scale worldwide, and is one of the technologies eligible for accommodating the increasing demand for renewable energy. However, wind energy is still not competitive compared to technologies that are based on fossil energy sources. Therefore, much wind energy research is focused on decreasing the cost of the energy that can be produced from the wind. The cost of energy can for example be decreased by ensuring that wind turbines are operated in a way that ensures that the maximum amount of energy is extracted, and that the turbines are not loaded excessively. The operation of a wind turbine is governed by a number of controllers that are based on a series of sensors and actuators. Classical wind turbine control utilizes sensors for measuring turbine parameters such as rotor speed, power and shaft torque, as well as actuators for applying generator torque and collective pitch angle changes. Thus, classical wind turbine control schemes are based on measurements of the effects of the inflow on the turbine. Therefore, the reactions of the control system to the inflow changes are inherently delayed compared to the actual inflow changes. Because of the inherent delay of the control system, the ability of the system to react promptly to inflow changes is limited. Control schemes that are based on inflow measurements have been developed to overcome the limitations of the classical wind turbine control system. By measuring the inflow directly, actuation can be initiated instantly as the inflow changes. If the inflow is measured upstream of the turbine, actuation can be initiated prior to the occurrence of a wind speed change at the turbine. Hereby, even the actuator delay can be compensated for. Upstream inflow measurements could for example be acquired using ''Light Detection and Ranging''. In this thesis, the potentials for improving the power production and decreasing the load variations of horizontal axis upwind turbines

  5. Organic Electroluminescent Sensor for Pressure Measurement

    Directory of Open Access Journals (Sweden)

    Tomohide Niimi

    2012-10-01

    Full Text Available We have proposed a novel concept of a pressure sensor called electroluminescent pressure sensor (ELPS based on oxygen quenching of electroluminescence. The sensor was fabricated as an organic light-emitting device (OLED with phosphorescent dyes whose phosphorescence can be quenched by oxygenmolecules, and with a polymer electrode which permeates oxygen molecules. The sensor was a single-layer OLED with Platinum (II octaethylporphine (PtOEP doped into poly(vinylcarbazole (PVK as an oxygen sensitive emissive layer and poly(3,4-ethylenedioxythiophene mixed with poly(styrenesulfonate (PEDOT:PSS as an oxygen permeating polymer anode. The pressure sensitivity of the fabricated ELPS sample was equivalent to that of the sensor excited by an illumination light source. Moreover, the pressure sensitivity of the sensor is equivalent to that of conventional pressure-sensitive paint (PSP, which is an optical pressure sensor based on photoluminescence.

  6. Large Capacitance Measurement by Multiple Uses of MBL Charge Sensor

    Science.gov (United States)

    Lee, Jung Sook; Chae, Min; Kim, Jung Bog

    2010-01-01

    A recent article by Morse described interesting electrostatics experiments using an MBL charge sensor. In this application, the charge sensor has a large capacitance compared to the charged test object, so nearly all charges can be transferred to the sensor capacitor from the capacitor to be measured. However, the typical capacitance of commercial…

  7. Hydrogel-based sensor for CO2 measurements

    NARCIS (Netherlands)

    Herber, S.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2004-01-01

    A hydrogel-based sensor is presented for CO2 measurements. The sensor consists of a pressure sensor and porous silicon cover. A pH-sensitive hydrogel is confined between the two parts. Furthermore the porous cover contains a bicarbonate solution and a gaspermeable membrane. CO2 reacts with the

  8. Design of Electric Field Sensors for Measurement of Electromagnetic Pulse

    Directory of Open Access Journals (Sweden)

    Hui ZHANG

    2014-01-01

    Full Text Available In this paper, a D-dot electric field sensor and a fiber-optic transmission electric field sensor are developed for measurement of electromagnetic pulse. The D-dot sensor is a differential model sensor without source and has a simple structure. The fiber-optic transmission sensor is in the type of small dipole antenna, which uses its outside shielding layer as a pair of antennas. Design of the sensor circuit and the test system are introduced in this paper. A calibration system for these pulsed field sensors is established and the test results verified the ability of the developed sensors for measurement of the standard electromagnetic pulse field (the half peak width is 25 ns and the rising time is 2.5 ns.

  9. Photonic Crystal Fiber Sensors for Strain and Temperature Measurement

    Directory of Open Access Journals (Sweden)

    Jian Ju

    2009-01-01

    Full Text Available This paper discusses the applications of photonic crystal fibers (PCFs for strain and temperature measurement. Long-period grating sensors and in-fiber modal interferometric sensors are described and compared with their conventional single-mode counterparts. The strain sensitivities of the air-silica PCF sensors are comparable or higher than those implemented in conventional single-mode fibers but the temperature sensitivities of the PCF sensors are much lower.

  10. Wind Turbine Load Mitigation based on Multivariable Robust Control and Blade Root Sensors

    Science.gov (United States)

    Díaz de Corcuera, A.; Pujana-Arrese, A.; Ezquerra, J. M.; Segurola, E.; Landaluze, J.

    2014-12-01

    This paper presents two H∞ multivariable robust controllers based on blade root sensors' information for individual pitch angle control. The wind turbine of 5 MW defined in the Upwind European project is the reference non-linear model used in this research work, which has been modelled in the GH Bladed 4.0 software package. The main objective of these controllers is load mitigation in different components of wind turbines during power production in the above rated control zone. The first proposed multi-input multi-output (MIMO) individual pitch H" controller mitigates the wind effect on the tower side-to-side acceleration and reduces the asymmetrical loads which appear in the rotor due to its misalignment. The second individual pitch H" multivariable controller mitigates the loads on the three blades reducing the wind effect on the bending flapwise and edgewise momentums in the blades. The designed H" controllers have been validated in GH Bladed and an exhaustive analysis has been carried out to calculate fatigue load reduction on wind turbine components, as well as to analyze load mitigation in some extreme cases.

  11. Wind Turbine Load Mitigation based on Multivariable Robust Control and Blade Root Sensors

    International Nuclear Information System (INIS)

    Corcuera, A Díaz de; Pujana-Arrese, A; Ezquerra, J M; Segurola, E; Landaluze, J

    2014-01-01

    This paper presents two H ∞ multivariable robust controllers based on blade root sensors' information for individual pitch angle control. The wind turbine of 5 MW defined in the Upwind European project is the reference non-linear model used in this research work, which has been modelled in the GH Bladed 4.0 software package. The main objective of these controllers is load mitigation in different components of wind turbines during power production in the above rated control zone. The first proposed multi-input multi-output (MIMO) individual pitch H'' controller mitigates the wind effect on the tower side-to-side acceleration and reduces the asymmetrical loads which appear in the rotor due to its misalignment. The second individual pitch H'' multivariable controller mitigates the loads on the three blades reducing the wind effect on the bending flapwise and edgewise momentums in the blades. The designed H'' controllers have been validated in GH Bladed and an exhaustive analysis has been carried out to calculate fatigue load reduction on wind turbine components, as well as to analyze load mitigation in some extreme cases

  12. A new fiber optic sensor for inner surface roughness measurement

    Science.gov (United States)

    Xu, Xiaomei; Liu, Shoubin; Hu, Hong

    2009-11-01

    In order to measure inner surface roughness of small holes nondestructively, a new fiber optic sensor is researched and developed. Firstly, a new model for surface roughness measurement is proposed, which is based on intensity-modulated fiber optic sensors and scattering modeling of rough surfaces. Secondly, a fiber optical measurement system is designed and set up. Under the help of new techniques, the fiber optic sensor can be miniaturized. Furthermore, the use of micro prism makes the light turn 90 degree, so the inner side surface roughness of small holes can be measured. Thirdly, the fiber optic sensor is gauged by standard surface roughness specimens, and a series of measurement experiments have been done. The measurement results are compared with those obtained by TR220 Surface Roughness Instrument and Form Talysurf Laser 635, and validity of the developed fiber optic sensor is verified. Finally, precision and influence factors of the fiber optic sensor are analyzed.

  13. Measured wind speed trends on the west coast of Canada

    Science.gov (United States)

    Tuller, Stanton E.

    2004-09-01

    Trends in measured wind speed are discussed for four stations on the west coast of Canada. Periods of record vary with the station. They begin in the late 1940s or the 1950s and run through to the early to mid 1990s. The most prominent feature of the time series was a decline in mean annual and winter wind speeds at Cape St James, Victoria International Airport, and Vancouver International Airport during the middle portion of the record. Declines in mean annual wind speed are matched by increases in the percentage of calms and decreases in high wind speed observations. The pressure gradient between Victoria, Vancouver and Comox, the Pacific North American index, the Pacific decadal oscillation index, and other climate elements in British Columbia and the northwestern USA show trends at roughly the same time, indicating a natural cause of the wind speed decrease. Comox Airport mean wind speeds increased, however, perhaps the result of reduced friction in the vicinity of the anemometer outweighing the decrease in the regional pressure gradient.

  14. Micro packaged MEMS pressure sensor for intracranial pressure measurement

    International Nuclear Information System (INIS)

    Liu Xiong; Yao Yan; Ma Jiahao; Zhang Zhaohua; Zhang Yanhang; Wang Qian; Ren Tianling

    2015-01-01

    This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to BioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Miniaturization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 μm 2 . It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm 2 . In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm 2 . Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10 −2 mV/kPa. (paper)

  15. Thermal effects influencing measurements in a supersonic blowdown wind tunnel

    Directory of Open Access Journals (Sweden)

    Vuković Đorđe S.

    2016-01-01

    Full Text Available During a supersonic run of a blowdown wind tunnel, temperature of air in the test section drops which can affect planned measurements. Adverse thermal effects include variations of the Mach and Reynolds numbers, variation of airspeed, condensation of moisture on the model, change of characteristics of the instrumentation in the model, et cetera. Available data on thermal effects on instrumentation are pertaining primarily to long-run-duration wind tunnel facilities. In order to characterize such influences on instrumentation in the models, in short-run-duration blowdown wind tunnels, temperature measurements were made in the wing-panel-balance and main-balance spaces of two wind tunnel models tested in the T-38 wind tunnel. The measurements showed that model-interior temperature in a run increased at the beginning of the run, followed by a slower drop and, at the end of the run, by a large temperature drop. Panel-force balance was affected much more than the main balance. Ways of reducing the unwelcome thermal effects by instrumentation design and test planning are discussed.

  16. A method of measuring and correcting tilt of anti - vibration wind turbines based on screening algorithm

    Science.gov (United States)

    Xiao, Zhongxiu

    2018-04-01

    A Method of Measuring and Correcting Tilt of Anti - vibration Wind Turbines Based on Screening Algorithm is proposed in this paper. First of all, we design a device which the core is the acceleration sensor ADXL203, the inclination is measured by installing it on the tower of the wind turbine as well as the engine room. Next using the Kalman filter algorithm to filter effectively by establishing a state space model for signal and noise. Then we use matlab for simulation. Considering the impact of the tower and nacelle vibration on the collected data, the original data and the filtering data are classified and stored by the Screening algorithm, then filter the filtering data to make the output data more accurate. Finally, we eliminate installation errors by using algorithm to achieve the tilt correction. The device based on this method has high precision, low cost and anti-vibration advantages. It has a wide range of application and promotion value.

  17. Development of a Wind Plant Large-Eddy Simulation with Measurement-Driven Atmospheric Inflow: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Quon, Eliot; Churchfield, Matthew; Cheung, Lawrence; Kern, Stefan

    2017-02-01

    This paper details the development of an aeroelastic wind plant model with large-eddy simulation (LES). The chosen LES solver is the Simulator for Wind Farm Applications (SOWFA) based on the OpenFOAM framework, coupled to NREL's comprehensive aeroelastic analysis tool, FAST. An atmospheric boundary layer (ABL) precursor simulation was constructed based on assessments of meteorological tower, lidar, and radar data over a 3-hour window. This precursor was tuned to the specific atmospheric conditions that occurred both prior to and during the measurement campaign, enabling capture of a night-to-day transition in the turbulent ABL. In the absence of height-varying temperature measurements, spatially averaged radar data were sufficient to characterize the atmospheric stability of the wind plant in terms of the shear profile, and near-ground temperature sensors provided a reasonable estimate of the ground heating rate describing the morning transition. A full aeroelastic simulation was then performed for a subset of turbines within the wind plant, driven by the precursor. Analysis of two turbines within the array, one directly waked by the other, demonstrated good agreement with measured time-averaged loads.

  18. Development of a Wind Plant Large-Eddy Simulation with Measurement-Driven Atmospheric Inflow

    Energy Technology Data Exchange (ETDEWEB)

    Quon, Eliot W.; Churchfield, Matthew J.; Cheung, Lawrence; Kern, Stefan

    2017-01-09

    This paper details the development of an aeroelastic wind plant model with large-eddy simulation (LES). The chosen LES solver is the Simulator for Wind Farm Applications (SOWFA) based on the OpenFOAM framework, coupled to NREL's comprehensive aeroelastic analysis tool, FAST. An atmospheric boundary layer (ABL) precursor simulation was constructed based on assessments of meteorological tower, lidar, and radar data over a 3-hour window. This precursor was tuned to the specific atmospheric conditions that occurred both prior to and during the measurement campaign, enabling capture of a night-to-day transition in the turbulent ABL. In the absence of height-varying temperature measurements, spatially averaged radar data were sufficient to characterize the atmospheric stability of the wind plant in terms of the shear profile, and near-ground temperature sensors provided a reasonable estimate of the ground heating rate describing the morning transition. A full aeroelastic simulation was then performed for a subset of turbines within the wind plant, driven by the precursor. Analysis of two turbines within the array, one directly waked by the other, demonstrated good agreement with measured time-averaged loads.

  19. Comparison of NWP wind speeds and directions to measured wind speeds and directions

    DEFF Research Database (Denmark)

    Astrup, Poul; Mikkelsen, Torben

    Numerical Weather Predictions (NWP) of wind speed and direction has been compared to measurements for seven German sites for nuclear power plants, and for Risø, the site of the Danish nuclear research reactors now being decommissioned . For the German sites the data cover approximately three month...

  20. Quality controls for wind measurement of a 1290-MHz boundary layer profiler under strong wind conditions.

    Science.gov (United States)

    Liu, Zhao; Zheng, Chaorong; Wu, Yue

    2017-09-01

    Wind profilers have been widely adopted to observe the wind field information in the atmosphere for different purposes. But accuracy of its observation has limitations due to various noises or disturbances and hence need to be further improved. In this paper, the data measured under strong wind conditions, using a 1290-MHz boundary layer profiler (BLP), are quality controlled via a composite quality control (QC) procedure proposed by the authors. Then, through the comparison with the data measured by radiosonde flights (balloon observations), the critical thresholds in the composite QC procedure, including consensus average threshold T 1 and vertical shear threshold T 3 , are systematically discussed. And the performance of the BLP operated under precipitation is also evaluated. It is found that to ensure the high accuracy and high data collectable rate, the optimal range of subsets is determined to be 4 m/s. Although the number of data rejected by the combined algorithm of vertical shear examination and small median test is quite limited, it is proved that the algorithm is quite useful to recognize the outlier with a large discrepancy. And the optimal wind shear threshold T 3 can be recommended as 5 ms -1 /100m. During patchy precipitation, the quality of data measured by the four oblique beams (using the DBS measuring technique) can still be ensured. After the BLP data are quality controlled by the composite QC procedure, the output can show good agreement with the balloon observation.

  1. Offshore Wind Turbine Foundation Model Validation with Wind Farm Measurements and Uncertainty Quantification

    DEFF Research Database (Denmark)

    Koukoura, Christina; Natarajan, Anand; Krogh, Thomas

    2013-01-01

    The variation in simulated monopile substructure loads is quantified by validating an aero-hydro-servo-elastic design tool with offshore foundation load measurements. A three bladed 3.6MW pitch controlled variable speed wind turbine for offshore monopile foundations is modeled in the HAWC2...

  2. Fundamentals for remote structural health monitoring of wind turbine blades - a pre-project. Annex D - Full-scale test of wind turbine blade, using sensors and NDT

    Energy Technology Data Exchange (ETDEWEB)

    Kristensen, O.J.D.; McGugan, M.; Sendrup, P.; Rheinlaender, J.; Rusborg, J.; Hansen, A.M.; Debel, C.P.; Soerensen, B.F.

    2002-05-01

    A 19.1 metre wind turbine blade was subjected to static tests. The purpose of the test series was to verify the abilities of different types of sensors to detect damage in wind turbine blades. Prior to each of the static test-series an artificial damage was made on the blade. The damage made for each test-series was surveyed during each series by acoustic emission, fiber optic micro bend displacement transducers and strain gauges. The propagation of the damage was determined by use of ultra sonic and X-ray surveillance during stops in the test series. By use of acoustic emission it was possible to measure damage propagation before the propagation was of visible size. By use of fiber optic micro bend displacement transducers and strain gauges it was possible to measure minor damage propagation. By use of both ultra sonic, and X-ray NDT-equipment it were possible to determine the size of propagated damage. (au)

  3. Arctic wind energy

    Energy Technology Data Exchange (ETDEWEB)

    Peltola, E. [Kemijoki Oy (Finland); Holttinen, H.; Marjaniemi, M. [VTT Energy, Espoo (Finland); Tammelin, B. [Finnish Meteorological Institute, Helsinki (Finland)

    1998-12-31

    Arctic wind energy research was aimed at adapting existing wind technologies to suit the arctic climatic conditions in Lapland. Project research work included meteorological measurements, instrument development, development of a blade heating system for wind turbines, load measurements and modelling of ice induced loads on wind turbines, together with the development of operation and maintenance practices in arctic conditions. As a result the basis now exists for technically feasible and economically viable wind energy production in Lapland. New and marketable products, such as blade heating systems for wind turbines and meteorological sensors for arctic conditions, with substantial export potential, have also been developed. (orig.)

  4. Arctic wind energy

    International Nuclear Information System (INIS)

    Peltola, E.; Holttinen, H.; Marjaniemi, M.; Tammelin, B.

    1998-01-01

    Arctic wind energy research was aimed at adapting existing wind technologies to suit the arctic climatic conditions in Lapland. Project research work included meteorological measurements, instrument development, development of a blade heating system for wind turbines, load measurements and modelling of ice induced loads on wind turbines, together with the development of operation and maintenance practices in arctic conditions. As a result the basis now exists for technically feasible and economically viable wind energy production in Lapland. New and marketable products, such as blade heating systems for wind turbines and meteorological sensors for arctic conditions, with substantial export potential, have also been developed. (orig.)

  5. The effect of winding and core support material on the thermal gain dependence of a fluxgate magnetometer sensor

    Science.gov (United States)

    Miles, David M.; Mann, Ian R.; Kale, Andy; Milling, David K.; Narod, Barry B.; Bennest, John R.; Barona, David; Unsworth, Martyn J.

    2017-10-01

    Fluxgate magnetometers are an important tool in geophysics and space physics but are typically sensitive to variations in sensor temperature. Changes in instrumental gain with temperature, thermal gain dependence, are thought to be predominantly due to changes in the geometry of the wire coils that sense the magnetic field and/or provide magnetic feedback. Scientific fluxgate magnetometers typically employ some form of temperature compensation and support and constrain wire sense coils with bobbins constructed from materials such as MACOR machinable ceramic (Corning Inc.) which are selected for their ultra-low thermal deformation rather than for robustness, cost, or ease of manufacturing. We present laboratory results comparing the performance of six geometrically and electrically matched fluxgate sensors in which the material used to support the windings and for the base of the sensor is varied. We use a novel, low-cost thermal calibration procedure based on a controlled sinusoidal magnetic source and quantitative spectral analysis to measure the thermal gain dependence of fluxgate magnetometer sensors at the ppm°C-1 level in a typical magnetically noisy university laboratory environment. We compare the thermal gain dependence of sensors built from MACOR, polyetheretherketone (PEEK) engineering plastic (virgin, 30 % glass filled and 30 % carbon filled), and acetal to examine the trade between the thermal properties of the material, the impact on the thermal gain dependence of the fluxgate, and the cost and ease of manufacture. We find that thermal gain dependence of the sensor varies as one half of the material properties of the bobbin supporting the wire sense coils rather than being directly related as has been historically thought. An experimental sensor constructed from 30 % glass-filled PEEK (21.6 ppm°C-1) had a thermal gain dependence within 5 ppm°C-1 of a traditional sensor constructed from MACOR ceramic (8.1 ppm°C-1). If a modest increase in thermal

  6. The effect of winding and core support material on the thermal gain dependence of a fluxgate magnetometer sensor

    Directory of Open Access Journals (Sweden)

    D. M. Miles

    2017-10-01

    Full Text Available Fluxgate magnetometers are an important tool in geophysics and space physics but are typically sensitive to variations in sensor temperature. Changes in instrumental gain with temperature, thermal gain dependence, are thought to be predominantly due to changes in the geometry of the wire coils that sense the magnetic field and/or provide magnetic feedback. Scientific fluxgate magnetometers typically employ some form of temperature compensation and support and constrain wire sense coils with bobbins constructed from materials such as MACOR machinable ceramic (Corning Inc. which are selected for their ultra-low thermal deformation rather than for robustness, cost, or ease of manufacturing. We present laboratory results comparing the performance of six geometrically and electrically matched fluxgate sensors in which the material used to support the windings and for the base of the sensor is varied. We use a novel, low-cost thermal calibration procedure based on a controlled sinusoidal magnetic source and quantitative spectral analysis to measure the thermal gain dependence of fluxgate magnetometer sensors at the ppm°C−1 level in a typical magnetically noisy university laboratory environment. We compare the thermal gain dependence of sensors built from MACOR, polyetheretherketone (PEEK engineering plastic (virgin, 30 % glass filled and 30 % carbon filled, and acetal to examine the trade between the thermal properties of the material, the impact on the thermal gain dependence of the fluxgate, and the cost and ease of manufacture. We find that thermal gain dependence of the sensor varies as one half of the material properties of the bobbin supporting the wire sense coils rather than being directly related as has been historically thought. An experimental sensor constructed from 30 % glass-filled PEEK (21.6 ppm°C−1 had a thermal gain dependence within 5 ppm°C−1 of a traditional sensor constructed from MACOR ceramic (8.1

  7. Analysis of Mexico wind tunnel measurements

    DEFF Research Database (Denmark)

    Schepers, J.G.; Boorsma, K.; Cho, T.

    This report describes the work performed within the first phase of IEA Task 29 Mexnext. In this IEA Task 29 a total of 20 organisations from 11 different countries collaborated in analysing the measurements which have been taken in the EU project ‘Mexico’. Within this Mexico project 9 European...

  8. Wind-Driven Wireless Networked System of Mobile Sensors for Mars Exploration

    Science.gov (United States)

    Davoodi, Faranak; Murphy, Neil

    2013-01-01

    A revolutionary way is proposed of studying the surface of Mars using a wind-driven network of mobile sensors: GOWON. GOWON would be a scalable, self-powered and autonomous distributed system that could allow in situ mapping of a wide range of environmental phenomena in a much larger portion of the surface of Mars compared to earlier missions. It could improve the possibility of finding rare phenomena such as "blueberries' or bio-signatures and mapping their occurrence, through random wind-driven search. It would explore difficult terrains that were beyond the reach of previous missions, such as regions with very steep slopes and cluttered surfaces. GOWON has a potentially long life span, as individual elements can be added to the array periodically. It could potentially provide a cost-effective solution for mapping wide areas of Martian terrain, enabling leaving a long-lasting sensing and searching infrastructure on the surface of Mars. The system proposed here addresses this opportunity using technology advances in a distributed system of wind-driven sensors, referred to as Moballs.

  9. Virtual sensors for on-line wheel wear and part roughness measurement in the grinding process.

    Science.gov (United States)

    Arriandiaga, Ander; Portillo, Eva; Sánchez, Jose A; Cabanes, Itziar; Pombo, Iñigo

    2014-05-19

    Grinding is an advanced machining process for the manufacturing of valuable complex and accurate parts for high added value sectors such as aerospace, wind generation, etc. Due to the extremely severe conditions inside grinding machines, critical process variables such as part surface finish or grinding wheel wear cannot be easily and cheaply measured on-line. In this paper a virtual sensor for on-line monitoring of those variables is presented. The sensor is based on the modelling ability of Artificial Neural Networks (ANNs) for stochastic and non-linear processes such as grinding; the selected architecture is the Layer-Recurrent neural network. The sensor makes use of the relation between the variables to be measured and power consumption in the wheel spindle, which can be easily measured. A sensor calibration methodology is presented, and the levels of error that can be expected are discussed. Validation of the new sensor is carried out by comparing the sensor's results with actual measurements carried out in an industrial grinding machine. Results show excellent estimation performance for both wheel wear and surface roughness. In the case of wheel wear, the absolute error is within the range of microns (average value 32 μm). In the case of surface finish, the absolute error is well below Ra 1 μm (average value 0.32 μm). The present approach can be easily generalized to other grinding operations.

  10. Measuring heart rate with optical sensor

    NARCIS (Netherlands)

    Barachi, M. (Mitra)

    2014-01-01

    The problem addressed in this report is to verify the possibility of using an optical sensor in the SaxShirt in order to extract the heart rate. There are specifically three questions that we try to address. 1) How is it possible to extract heart rate (BPM) from the optical sensor? 2) Is it

  11. Active Fault-Tolerant Control for Wind Turbine with Simultaneous Actuator and Sensor Faults

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2017-01-01

    Full Text Available The purpose of this paper is to show a novel fault-tolerant tracking control (FTC strategy with robust fault estimation and compensating for simultaneous actuator sensor faults. Based on the framework of fault-tolerant control, developing an FTC design method for wind turbines is a challenge and, thus, they can tolerate simultaneous pitch actuator and pitch sensor faults having bounded first time derivatives. The paper’s key contribution is proposing a descriptor sliding mode method, in which for establishing a novel augmented descriptor system, with which we can estimate the state of system and reconstruct fault by designing descriptor sliding mode observer, the paper introduces an auxiliary descriptor state vector composed by a system state vector, actuator fault vector, and sensor fault vector. By the optimized method of LMI, the conditions for stability that estimated error dynamics are set up to promote the determination of the parameters designed. With this estimation, and designing a fault-tolerant controller, the system’s stability can be maintained. The effectiveness of the design strategy is verified by implementing the controller in the National Renewable Energy Laboratory’s 5-MW nonlinear, high-fidelity wind turbine model (FAST and simulating it in MATLAB/Simulink.

  12. A new wind vane for the measurement of atmospheric turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Parker, M.J.; Heverly, M.

    1997-02-01

    A Cooperative Research and Development Agreement (CRADA) between Met One Instruments, Incorporated (Met One) and Westinghouse Savannah River Company (WSRC) was created to develop a new wind vane that more accurately measures atmospheric turbulence. Through a process that had several phases, Met One created a prototype vane that was designed to attach to the existing Model 1585 Bi-Directional Wind Vane instrument structure. The prototype contained over 20% less mass to enhance responsiveness, which was also increased through the use of a teardrop-shaped fin structure. The prototype vane can be readily manufactured for commercial retail. Tests in wind tunnel of Building 735-7A, the Meteorological Engineering Facility, indicated that the new vane has a superior starting threshold of less than 0.14 meter per second, a delay distance of 0.72 meter, and a damping ratio of 0.4. The relative accuracy of less than one degree is unchanged from the previous design. The vane bias was acceptable at 0.8 degree for the horizontal wind angle, but was slightly high at 1.4 degree for the verticle wind angle. The high value of the verticle wind angle bias can most likely be reduced to the desired less than one degree value with standard manufacturing production techniques. The durability of the prototype vane was not tested in the field but is expected to be slightly less due to the use of hollow rather than foam-filled fins. However, the loss of some durability is more than compensated with increased sensitivity at low wind speeds. Field testing of the prototype is required to test for adequacy of durability.

  13. High resolution wind turbine wake measurements with a scanning lidar

    DEFF Research Database (Denmark)

    Herges, T. G.; Maniaci, D. C.; Naughton, B. T.

    2017-01-01

    High-resolution lidar wake measurements are part of an ongoing field campaign being conducted at the Scaled Wind Farm Technology facility by Sandia National Laboratories and the National Renewable Energy Laboratory using a customized scanning lidar from the Technical University of Denmark. One...

  14. Canopy wake measurements using multiple scanning wind LiDARs

    Science.gov (United States)

    Markfort, C. D.; Carbajo Fuertes, F.; Iungo, V.; Stefan, H. G.; Porte-Agel, F.

    2014-12-01

    Canopy wakes have been shown, in controlled wind tunnel experiments, to significantly affect the fluxes of momentum, heat and other scalars at the land and water surface over distances of ˜O(1 km), see Markfort et al. (EFM, 2013). However, there are currently no measurements of the velocity field downwind of a full-scale forest canopy. Point-based anemometer measurements of wake turbulence provide limited insight into the extent and details of the wake structure, whereas scanning Doppler wind LiDARs can provide information on how the wake evolves in space and varies over time. For the first time, we present measurements of the velocity field in the wake of a tall patch of forest canopy. The patch consists of two uniform rows of 40-meter tall deciduous, plane trees, which border either side of the Allée de Dorigny, near the EPFL campus. The canopy is approximately 250 m long, and it is approximately 40 m wide, along the direction of the wind. A challenge faced while making field measurements is that the wind rarely intersects a canopy normal to the edge. The resulting wake flow may be deflected relative to the mean inflow. Using multiple LiDARs, we measure the evolution of the wake due to an oblique wind blowing over the canopy. One LiDAR is positioned directly downwind of the canopy to measure the flow along the mean wind direction and the other is positioned near the canopy to evaluate the transversal component of the wind and how it varies with downwind distance from the canopy. Preliminary results show that the open trunk space near the base of the canopy results in a surface jet that can be detected just downwind of the canopy and farther downwind dissipates as it mixes with the wake flow above. A time-varying recirculation zone can be detected by the periodic reversal of the velocity near the surface, downwind of the canopy. The implications of canopy wakes for measurement and modeling of surface fluxes will be discussed.

  15. MEASUREMENT OF WIND SPEED FROM COOLING LAKE THERMAL IMAGERY

    International Nuclear Information System (INIS)

    Garrett, A.; Kurzeja, R.; Villa-Aleman, E.; Tuckfield, C.; Pendergast, M.

    2009-01-01

    The Savannah River National Laboratory (SRNL) collected thermal imagery and ground truth data at two commercial power plant cooling lakes to investigate the applicability of laboratory empirical correlations between surface heat flux and wind speed, and statistics derived from thermal imagery. SRNL demonstrated in a previous paper (1] that a linear relationship exists between the standard deviation of image temperature and surface heat flux. In this paper, SRNL will show that the skewness of the temperature distribution derived from cooling lake thermal images correlates with instantaneous wind speed measured at the same location. SRNL collected thermal imagery, surface meteorology and water temperatures from helicopters and boats at the Comanche Peak and H. B. Robinson nuclear power plant cooling lakes. SRNL found that decreasing skewness correlated with increasing wind speed, as was the case for the laboratory experiments. Simple linear and orthogonal regression models both explained about 50% of the variance in the skewness - wind speed plots. A nonlinear (logistic) regression model produced a better fit to the data, apparently because the thermal convection and resulting skewness are related to wind speed in a highly nonlinear way in nearly calm and in windy conditions

  16. Field measurements in the wake of a model wind turbine

    International Nuclear Information System (INIS)

    Pol, Suhas; Taylor, Amelia; Doostalab, Ali; Novoa, Santiago; Castillo, Luciano; Bilbao, Argenis; Sheng, Jian; Giesselmann, Michael; Westergaard, Carsten; Hussain, Fazle; Ren, Beibei; Glauser, Mark

    2014-01-01

    As a first step to study the dynamics of a wind farm' we experimentally explored the flow field behind a single wind turbine of diameter 1.17 m at a hub height of 6.25 m. A 10 m tower upstream of the wind farm characterizes the atmospheric conditions and its influence on the wake evolution. A vertical rake of sonic anemometers is clustered around the hub height on a second tower' 6D downstream of the turbine. We present preliminary observations from a 1- hour block of data recorded in near-neutral atmospheric conditions. The ratio of the standard deviation of power to the inflow velocity is greater than three' revealing adverse effects of inflow turbulence on the power and load fluctuations. Furthermore' the wake defect and Reynolds stress and its gradient are pronounced at 6D. The flux of energy due to Reynolds stresses is similar to that reported in wind tunnel studies. The swirl and mixing produces a constant temperature wake which results in a density jump across the wake interface. Further field measurements will explore the dynamics of a model wind farm' including the effects of atmospheric variability

  17. Simulation of the Impact of New Aircraft- and Satellite-based Ocean Surface Wind Measurements on Estimates of Hurricane Intensity

    Science.gov (United States)

    Uhlhorn, Eric; Atlas, Robert; Black, Peter; Buckley, Courtney; Chen, Shuyi; El-Nimri, Salem; Hood, Robbie; Johnson, James; Jones, Linwood; Miller, Timothy; hide

    2009-01-01

    The Hurricane Imaging Radiometer (HIRAD) is a new airborne microwave remote sensor currently under development to enhance real-time hurricane ocean surface wind observations. HIRAD builds on the capabilities of the Stepped Frequency Microwave Radiometer (SFMR), which now operates on NOAA P-3, G-4, and AFRC C-130 aircraft. Unlike the SFMR, which measures wind speed and rain rate along the ground track directly beneath the aircraft, HIRAD will provide images of the surface wind and rain field over a wide swath (approximately 3 times the aircraft altitude). To demonstrate potential improvement in the measurement of peak hurricane winds, we present a set of Observing System Simulation Experiments (OSSEs) in which measurements from the new instrument as well as those from existing platforms (air, surface, and space-based) are simulated from the output of a high-resolution (approximately 1.7 km) numerical model. Simulated retrieval errors due to both instrument noise as well as model function accuracy are considered over the expected range of incidence angles, wind speeds and rain rates. Based on numerous simulated flight patterns and data source combinations, statistics are developed to describe relationships between the observed and true (from the model s perspective) peak wind speed. These results have implications for improving the estimation of hurricane intensity (as defined by the peak sustained wind anywhere in the storm), which may often go un-observed due to sampling limitations.

  18. Wind Turbine Wake Characterization from Temporally Disjunct 3-D Measurements

    Directory of Open Access Journals (Sweden)

    Paula Doubrawa

    2016-11-01

    Full Text Available Scanning LiDARs can be used to obtain three-dimensional wind measurements in and beyond the atmospheric surface layer. In this work, metrics characterizing wind turbine wakes are derived from LiDAR observations and from large-eddy simulation (LES data, which are used to recreate the LiDAR scanning geometry. The metrics are calculated for two-dimensional planes in the vertical and cross-stream directions at discrete distances downstream of a turbine under single-wake conditions. The simulation data are used to estimate the uncertainty when mean wake characteristics are quantified from scanning LiDAR measurements, which are temporally disjunct due to the time that the instrument takes to probe a large volume of air. Based on LES output, we determine that wind speeds sampled with the synthetic LiDAR are within 10% of the actual mean values and that the disjunct nature of the scan does not compromise the spatial variation of wind speeds within the planes. We propose scanning geometry density and coverage indices, which quantify the spatial distribution of the sampled points in the area of interest and are valuable to design LiDAR measurement campaigns for wake characterization. We find that scanning geometry coverage is important for estimates of the wake center, orientation and length scales, while density is more important when seeking to characterize the velocity deficit distribution.

  19. Determination of the thermospheric neutral wind from incoherent scatter radar measurements

    International Nuclear Information System (INIS)

    Haeggstroem, I.; Murdin, J.; Rees, D.

    1984-11-01

    Measurements made by the EISCAT UHF incoherent scatter radar are used to derive thermospheric winds. The derived wind is compared to Fabry-Perot interferometer measurements of the neutral wind made simultaneously. The uncertainties in the radar derived wind are discussed. (author)

  20. Multi-life-stage monitoring system based on fibre bragg grating sensors for more reliable wind turbine rotor blades: Experimental and numerical analysis of deformation and failure in composite materials

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira

    , design and optimisation of offshore wind turbines. The MareWint main scientific objective is to optimise the design of offshore wind turbines, maximise reliability, and minimise maintenance costs. Integrated within the innovative rotor blades work-package, this PhD project is focused on damage analysis...... are used to improve the design process, and the implemented sensor are used to control the manufacturing and operation stage of a wind turbine rotor blade. The FBG sensors measurement principle is analysed from a multi-life-stage (design, material testing, manufacturing, and operation) perspective......, and supported/validated by numerical models, software tools, signal post-processing, and experimental validation. The damage in the wind turbine rotor blade is analysed from a material perspective (fibre reinforced polymers) and used as a design property, meaning that damage is accepted in an operational wind...

  1. Advanced Sensors for Airborne Magnetic Measurements

    National Research Council Canada - National Science Library

    Bobb, L

    2001-01-01

    Numerous ground tests and platform tests were conducted to evaluate platform integration issues and the performance of the POLATOMIC 2000 magnetometer, a laser-pumped helium-4 total magnetic field sensor...

  2. Measuring power output intermittency and unsteady loading in a micro wind farm model

    OpenAIRE

    Bossuyt, Juliaan; Howland, Michael; Meneveau, Charles; Meyers, Johan

    2016-01-01

    In this study porous disc models are used as a turbine model for a wind-tunnel wind farm experiment, allowing the measurement of the power output, thrust force and spatially averaged incoming velocity for every turbine. The model's capabilities for studying the unsteady turbine loading, wind farm power output intermittency and spatio temporal correlations between wind turbines are demonstrated on an aligned wind farm, consisting of 100 wind turbine models.

  3. A Power-Frequency Electric Field Sensor for Portable Measurement.

    Science.gov (United States)

    Xiao, Dongping; Ma, Qichao; Xie, Yutong; Zheng, Qi; Zhang, Zhanlong

    2018-03-31

    In this paper, a new type of electric field sensor is proposed for the health and safety protection of inspection staff in high-voltage environments. Compared with the traditional power frequency electric field measurement instruments, the portable instrument has some special performance requirements and, thus, a new kind of double spherical shell sensor is presented. First, the mathematical relationships between the induced voltage of the sensor, the output voltage of the measurement circuit, and the original electric field in free space are deduced theoretically. These equations show the principle of the proposed sensor to measure the electric field and the effect factors of the measurement. Next, the characteristics of the sensor are analyzed through simulation. The simulation results are in good agreement with the theoretical analysis. The influencing rules of the size and material of the sensor on the measurement results are summarized. Then, the proposed sensor and the matching measurement system are used in a physical experiment. After calibration, the error of the measurement system is discussed. Lastly, the directional characteristic of the proposed sensor is experimentally tested.

  4. A comparison of oxygen saturation measurements obtained from a 'blue sensor' with a standard sensor.

    Science.gov (United States)

    Mawson, Isabel E; Dawson, Jennifer A; Donath, Susan M; Davis, Peter G

    2011-10-01

    The study aims to investigate pulse oximetry measurements from a 'blue' pulse oximeter sensor against measurements from a 'standard' pulse oximeter sensor in newly born infants. Immediately after birth, both sensors were attached to the infant, one to each foot. SpO₂ measurements were recorded simultaneously from each sensor for 10 min. Agreement between pairs of SpO₂ measurements were calculated using Bland-Altman analysis. Thirty-one infants were studied. There was good correlation between simultaneous SpO₂ measurements from both sensors (r² = 0.75). However, the mean difference between 'blue' and 'standard' sensors was -1.6%, with wide 95% limits of agreement +18.4 to -21.6%. The range of mean difference between sensors from each infant ranged from -20 to +20. The mean difference between the blue and standard sensor SpO₂ measurements is not clinically important. © 2011 The Authors. Journal of Paediatrics and Child Health © 2011 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

  5. Fiber Optic Displacement Sensor for Measuring Cholesterol Concentration

    Directory of Open Access Journals (Sweden)

    Moh. Budiyanto

    2017-11-01

    Full Text Available A simple design of a cholesterol concentration detection is proposed and demonstrated using a fiber optic displacement sensor based on an intensity modulation technique. The proposed sensor uses a bundled plastic optical fiber (POF as a probe in conjunction with a flat mirror as a target. It is obtained that the peak voltage reduces with increasing cholesterol concentration. The sensor is capable of measuring the cholesterol concentration ranging from 0 to 300 ppm in a distilled water with a measured sensitivity of 0.01 mV/ppm, a linearity of more than 99.62 % and a resolution of 3.9188 ppm. The proposed sensor also shows a high degree of stability and good repeatability. The simplicity of design, accuracy, flexible dynamic range, and the low cost of fabrication are favorable attributes of the sensor and beneficial for real- field applications. Fiber optic sensors

  6. Flying with the wind: Scale dependency of speed and direction measurements in modelling wind support in avian flight

    Science.gov (United States)

    Safi, Kamran; Kranstauber, Bart; Weinzierl, Rolf P.; Griffin, Larry; Reese, Eileen C.; Cabot, David; Cruz, Sebastian; Proaño, Carolina; Takekawa, John Y.; Newman, Scott H.; Waldenström, Jonas; Bengtsson, Daniel; Kays, Roland; Wikelski, Martin; Bohrer, Gil

    2013-01-01

    Background: Understanding how environmental conditions, especially wind, influence birds' flight speeds is a prerequisite for understanding many important aspects of bird flight, including optimal migration strategies, navigation, and compensation for wind drift. Recent developments in tracking technology and the increased availability of data on large-scale weather patterns have made it possible to use path annotation to link the location of animals to environmental conditions such as wind speed and direction. However, there are various measures available for describing not only wind conditions but also the bird's flight direction and ground speed, and it is unclear which is best for determining the amount of wind support (the length of the wind vector in a bird’s flight direction) and the influence of cross-winds (the length of the wind vector perpendicular to a bird’s direction) throughout a bird's journey.Results: We compared relationships between cross-wind, wind support and bird movements, using path annotation derived from two different global weather reanalysis datasets and three different measures of direction and speed calculation for 288 individuals of nine bird species. Wind was a strong predictor of bird ground speed, explaining 10-66% of the variance, depending on species. Models using data from different weather sources gave qualitatively similar results; however, determining flight direction and speed from successive locations, even at short (15 min intervals), was inferior to using instantaneous GPS-based measures of speed and direction. Use of successive location data significantly underestimated the birds' ground and airspeed, and also resulted in mistaken associations between cross-winds, wind support, and their interactive effects, in relation to the birds' onward flight.Conclusions: Wind has strong effects on bird flight, and combining GPS technology with path annotation of weather variables allows us to quantify these effects for

  7. Fundamentals for remote structural health monitoring of wind turbine blades - a preproject. Annex A. Cost-benefit for embedded sensors in large wind turbine blades

    DEFF Research Database (Denmark)

    Hansen, L.G.; Lading, Lars

    2002-01-01

    -bladed 2MW turbine placed offshore either without sensors or with sensors are compared. The price of a structural health monitoring system of a price of 100 000 DKK (per tur-bine) results in a break-eventime of about 3 years. For a price of 300 000 DKK the break-even time is about 8 years. However......This report contains the results of a cost-benefit analysis for the use of embed-ded sensors for damage detection in large wind turbine blades - structural health monitoring - (in connection with remote surveillance) of large wind turbine placedoff-shore. The total operating costs of a three......, the cost/benefit analysis has large uncertainties....

  8. Evaluating nanoparticle sensor design for intracellular pH measurements.

    Science.gov (United States)

    Benjaminsen, Rikke V; Sun, Honghao; Henriksen, Jonas R; Christensen, Nynne M; Almdal, Kristoffer; Andresen, Thomas L

    2011-07-26

    Particle-based nanosensors have over the past decade been designed for optical fluorescent-based ratiometric measurements of pH in living cells. However, quantitative and time-resolved intracellular measurements of pH in endosomes and lysosomes using particle nanosensors are challenging, and there is a need to improve measurement methodology. In the present paper, we have successfully carried out time-resolved pH measurements in endosomes and lyosomes in living cells using nanoparticle sensors and show the importance of sensor choice for successful quantification. We have studied two nanoparticle-based sensor systems that are internalized by endocytosis and elucidated important factors in nanosensor design that should be considered in future development of new sensors. From our experiments it is clear that it is highly important to use sensors that have a broad measurement range, as erroneous quantification of pH is an unfortunate result when measuring pH too close to the limit of the sensitive range of the sensors. Triple-labeled nanosensors with a pH measurement range of 3.2-7.0, which was synthesized by adding two pH-sensitive fluorophores with different pK(a) to each sensor, seem to be a solution to some of the earlier problems found when measuring pH in the endosome-lysosome pathway.

  9. Comparing different CFD wind turbine modelling approaches with wind tunnel measurements

    International Nuclear Information System (INIS)

    Kalvig, Siri; Hjertager, Bjørn; Manger, Eirik

    2014-01-01

    The performance of a model wind turbine is simulated with three different CFD methods: actuator disk, actuator line and a fully resolved rotor. The simulations are compared with each other and with measurements from a wind tunnel experiment. The actuator disk is the least accurate and most cost-efficient, and the fully resolved rotor is the most accurate and least cost-efficient. The actuator line method is believed to lie in between the two ends of the scale. The fully resolved rotor produces superior wake velocity results compared to the actuator models. On average it also produces better results for the force predictions, although the actuator line method had a slightly better match for the design tip speed. The open source CFD tool box, OpenFOAM, was used for the actuator disk and actuator line calculations, whereas the market leading commercial CFD code, ANSYS/FLUENT, was used for the fully resolved rotor approach

  10. Field measurement of wind pressure and wind-induced vibration of large-span spatial cable-truss system under strong wind or typhoon

    Directory of Open Access Journals (Sweden)

    ZHANG Zhihong

    2013-10-01

    Full Text Available In order to ensure wind-resistance safety of large-span pre-stressed flexible system in southeast coast area of China,and to prepare something for revising of current codes of practice or technical standards,the present paper conducts field measurement of wind pressure and wind-induced vibration of a practical and typical large-span spatial cable-truss system-lunar stadium in Yueqing city.Wind loading and wind effects on full-scale structure under strong wind or typhoon in real architectural environment can be obtained directly and effectively.Field measurement is the best way to investigate the wind loading property,wind effects,and wind-structure interactions of large-span flexible system.Measured data will be highly valuable for scientific research and practical design.On the other hand,it also provides the basis of wind-resistance safety design of this kind of tension structures.If any creative development,it would dramatically improve the research level of large-span pre-stressed flexible system in our country.

  11. Ten years statistics of wind direction and wind velocity measurements performed at the Karlsruhe Nuclear Research Center

    International Nuclear Information System (INIS)

    Becker, M.; Dilger, H.

    1979-06-01

    The measurements of wind direction and wind velocity performed at 60 m and 200 m height were evaluated for one year each and frequency distributions of the measured values were established. The velocity was divided into 1 m/s steps and the direction into 10 0 sectors. The frequency distribution of the wind direction reveals three maxima located in the southwest, northeast and north, respectively. The maximum of the frequency distribution of the wind velocity occurs between 4 and 5 m/s at 200 m height and between 3 and 4 m/s at 60 m height. (orig.) [de

  12. Calibrating airborne measurements of airspeed, pressure and temperature using a Doppler laser air-motion sensor

    Directory of Open Access Journals (Sweden)

    W. A. Cooper

    2014-09-01

    Full Text Available A new laser air-motion sensor measures the true airspeed with a standard uncertainty of less than 0.1 m s−1 and so reduces uncertainty in the measured component of the relative wind along the longitudinal axis of the aircraft to about the same level. The calculated pressure expected from that airspeed at the inlet of a pitot tube then provides a basis for calibrating the measurements of dynamic and static pressure, reducing standard uncertainty in those measurements to less than 0.3 hPa and the precision applicable to steady flight conditions to about 0.1 hPa. These improved measurements of pressure, combined with high-resolution measurements of geometric altitude from the global positioning system, then indicate (via integrations of the hydrostatic equation during climbs and descents that the offset and uncertainty in temperature measurement for one research aircraft are +0.3 ± 0.3 °C. For airspeed, pressure and temperature, these are significant reductions in uncertainty vs. those obtained from calibrations using standard techniques. Finally, it is shown that although the initial calibration of the measured static and dynamic pressures requires a measured temperature, once calibrated these measured pressures and the measurement of airspeed from the new laser air-motion sensor provide a measurement of temperature that does not depend on any other temperature sensor.

  13. Multifunctional TENG for Blue Energy Scavenging and Self-Powered Wind-Speed Sensor

    KAUST Repository

    Xi, Yi

    2017-02-17

    Triboelectric nanogenerator (TENG) has been considered to be a more effective technology to harvest various types of mechanic vibration energies such as wind energy, water energy in the blue energy, and so on. Considering the vast energy from the blue oceans, harvesting of the water energy has attracted huge attention. There are two major types of “mechanical” water energy, water wave energy in random direction and water flow kinetic energy. However, although the most reported TENG can be used to efficiently harvest one type of water energy, to simultaneously collect two or more types of such energy still remains challenging. In this work, two different freestanding, multifunctional TENGs are successfully developed that can be used to harvest three types of energies including water waves, air flowing, and water flowing. These two new TENGs designed in accordance with the same freestanding model yield the output voltages of 490 and ≈100 V with short circuit currents of 24 and 2.7 µA, respectively, when operated at a rotation frequency of 200 rpm and the movement frequency of 3 Hz. Moreover, the developed multifunctional TENG can also be explored as a self-powered speed sensor of wind by correlating the short-circuit current with the wind speed.

  14. Evaluating Nanoparticle Sensor Design for Intracellular pH Measurements

    DEFF Research Database (Denmark)

    Benjaminsen, Rikke Vicki; Sun, Honghao; Henriksen, Jonas Rosager

    2011-01-01

    Particle-based nanosensors have over the last decade been designed for optical fluorescent-based ratiometric measurements of pH in living cells. However, quantitative and time-resolved intracellular measurements of pH in endosomes and lysosomes using particle nanosensors is challenging...... and there is a need to improve measurement methodology. In the present paper, we have successfully carried out time resolved pH measurements in endosomes and lyosomes in living cells using nanoparticle sensors and show the importance of sensor choice for successful quantification. We have studied two nanoparticle...... quantification of pH is an unfortunate result when measuring pH too close to the limit of the sensitive range of the sensors. Triple-labeled nanosensors with a pH measurement range of 3.2-7.0, which was synthesized by adding two pH-sensitive fluorophores with different pKa to each sensor, seem to be a solution...

  15. Optical sensor for measuring humidity, strain and temperature

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to an optical sensor (100) adapted to measure at least three physical parameters, said optical sensor comprising a polymer-based optical waveguide structure comprising a first Bragg grating structure (101) being adapted to provide information about a first, a second...

  16. NATURAL USER INTERFACE SENSORS FOR HUMAN BODY MEASUREMENT

    Directory of Open Access Journals (Sweden)

    J. Boehm

    2012-08-01

    Full Text Available The recent push for natural user interfaces (NUI in the entertainment and gaming industry has ushered in a new era of low cost three-dimensional sensors. While the basic idea of using a three-dimensional sensor for human gesture recognition dates some years back it is not until recently that such sensors became available on the mass market. The current market leader is PrimeSense who provide their technology for the Microsoft Xbox Kinect. Since these sensors are developed to detect and observe human users they should be ideally suited to measure the human body. We describe the technology of a line of NUI sensors and assess their performance in terms of repeatability and accuracy. We demonstrate the implementation of a prototype scanner integrating several NUI sensors to achieve full body coverage. We present the results of the obtained surface model of a human body.

  17. Natural User Interface Sensors for Human Body Measurement

    Science.gov (United States)

    Boehm, J.

    2012-08-01

    The recent push for natural user interfaces (NUI) in the entertainment and gaming industry has ushered in a new era of low cost three-dimensional sensors. While the basic idea of using a three-dimensional sensor for human gesture recognition dates some years back it is not until recently that such sensors became available on the mass market. The current market leader is PrimeSense who provide their technology for the Microsoft Xbox Kinect. Since these sensors are developed to detect and observe human users they should be ideally suited to measure the human body. We describe the technology of a line of NUI sensors and assess their performance in terms of repeatability and accuracy. We demonstrate the implementation of a prototype scanner integrating several NUI sensors to achieve full body coverage. We present the results of the obtained surface model of a human body.

  18. Wind-tunnel investigation of the flow correction for a model-mounted angle of attack sensor at angles of attack from -10 deg to 110 deg. [Langley 12-foot low speed wind tunnel test

    Science.gov (United States)

    Moul, T. M.

    1979-01-01

    A preliminary wind tunnel investigation was undertaken to determine the flow correction for a vane angle of attack sensor over an angle of attack range from -10 deg to 110 deg. The sensor was mounted ahead of the wing on a 1/5 scale model of a general aviation airplane. It was shown that the flow correction was substantial, reaching about 15 deg at an angle of attack of 90 deg. The flow correction was found to increase as the sensor was moved closer to the wing or closer to the fuselage. The experimentally determined slope of the flow correction versus the measured angle of attack below the stall angle of attack agreed closely with the slope of flight data from a similar full scale airplane.

  19. Biomedical sensor for transcutaneous oxygen measurements using thick film technology

    OpenAIRE

    Lam, Yu-Zhi (Liza)

    2003-01-01

    The measurement of the partial pressure of oxygen in arterial blood is essential for the analysis of a patient's respiratory condition. There are several commercially available methods and systems to measure this parameter transcutaneously. However, they tend to be cumbersome and costly. To overcome the disadvantages presented, a new type of sensor for transcutaneous blood gas measurement was investigated, employing thick film technology, which is an excellent technique to produce sensors in ...

  20. Customized DSP-based vibration measurement for wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    LaWhite, N.E.; Cohn, K.E. [Second Wind Inc., Somerville, MA (United States)

    1996-12-31

    As part of its Advanced Distributed Monitoring System (ADMS) project funded by NREL, Second Wind Inc. is developing a new vibration measurement system for use with wind turbines. The system uses low-cost accelerometers originally designed for automobile airbag crash-detection coupled with new software executed on a Digital Signal Processor (DSP) device. The system is envisioned as a means to monitor the mechanical {open_quotes}health{close_quotes} of the wind turbine over its lifetime. In addition the system holds promise as a customized emergency vibration detector. The two goals are very different and it is expected that different software programs will be executed for each function. While a fast Fourier transform (FFT) signature under given operating conditions can yield much information regarding turbine condition, the sampling period and processing requirements make it inappropriate for emergency condition monitoring. This paper briefly reviews the development of prototype DSP and accelerometer hardware. More importantly, it reviews our work to design prototype vibration alarm filters. Two-axis accelerometer test data from the experimental FloWind vertical axis wind turbine is analyzed and used as a development guide. Two levels of signal processing are considered. The first uses narrow band pre-processing filters at key fundamental frequencies such as the 1P, 2P and 3P. The total vibration energy in each frequency band is calculated and evaluated as a possible alarm trigger. In the second level of signal processing, the total vibration energy in each frequency band is further decomposed using the two-axis directional information. Directional statistics are calculated to differentiate between linear translations and circular translations. After analyzing the acceleration statistics for normal and unusual operating conditions, the acceleration processing system described could be used in automatic early detection of fault conditions. 9 figs.

  1. A novel capacitance sensor for fireside corrosion measurement

    Science.gov (United States)

    Ban, Heng; Li, Zuoping

    2009-11-01

    Fireside corrosion in coal-fired power plants is a leading mechanism for boiler tube failures. Online monitoring of fireside corrosion can provide timely data to plant operators for mitigation implementation. This paper presents a novel sensor concept for measuring metal loss based on electrical capacitance. Laboratory-scale experiments demonstrated the feasibility of design, fabrication, and operation of the sensor. The fabrication of the prototype sensor involved sputtering deposition of a thin metal coating with varying thickness on a ceramic substrate. Corrosion metal loss resulted in a proportional decrease in electrical capacitance of the sensor. Laboratory experiments using a muffle furnace with an oxidation environment demonstrated that low carbon steel coatings on ceramic substrate survived cyclic temperatures over 500 °C. Measured corrosion rates of sputtered coating in air had an Arrhenius exponential dependence on temperature, with metal thickness loss ranging from 2.0 nm/h at 200 °C to 2.0 μm/h at 400 °C. Uncertainty analysis indicated that the overall measurement uncertainty was within 4%. The experimental system showed high signal-to-noise ratio, and the sensor could measure submicrometer metal thickness changes. The laboratory experiments demonstrated that the sensor concept and measurement system are capable of short term, online monitoring of metal loss, indicating the potential for the sensor to be used for fireside corrosion monitoring and other metal loss measurement.

  2. Modelling and Measuring Flow and Wind Turbine Wakes in Large Wind Farms Offshore

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Hansen, Kurt Schaldemose; Frandsen, Sten Tronæs

    2009-01-01

    power losses due to wakes and loads. The research presented is part of the EC-funded UpWind project, which aims to radically improve wind turbine and wind farm models in order to continue to improve the costs of wind energy. Reducing wake losses, or even reduce uncertainties in predicting power losses...

  3. Active self-testing noise measurement sensors for large-scale environmental sensor networks.

    Science.gov (United States)

    Domínguez, Federico; Cuong, Nguyen The; Reinoso, Felipe; Touhafi, Abdellah; Steenhaut, Kris

    2013-12-13

    Large-scale noise pollution sensor networks consist of hundreds of spatially distributed microphones that measure environmental noise. These networks provide historical and real-time environmental data to citizens and decision makers and are therefore a key technology to steer environmental policy. However, the high cost of certified environmental microphone sensors render large-scale environmental networks prohibitively expensive. Several environmental network projects have started using off-the-shelf low-cost microphone sensors to reduce their costs, but these sensors have higher failure rates and produce lower quality data. To offset this disadvantage, we developed a low-cost noise sensor that actively checks its condition and indirectly the integrity of the data it produces. The main design concept is to embed a 13 mm speaker in the noise sensor casing and, by regularly scheduling a frequency sweep, estimate the evolution of the microphone's frequency response over time. This paper presents our noise sensor's hardware and software design together with the results of a test deployment in a large-scale environmental network in Belgium. Our middle-range-value sensor (around €50) effectively detected all experienced malfunctions, in laboratory tests and outdoor deployments, with a few false positives. Future improvements could further lower the cost of our sensor below €10.

  4. Analysis of a ferrofluid core differential transformer tilt measurement sensor

    Energy Technology Data Exchange (ETDEWEB)

    Medvegy, T.; Molnár, Á.; Molnár, G.; Gugolya, Z.

    2017-04-15

    In our work, we developed a ferrofluid core differential transformer sensor, which can be used to measure tilt and acceleration. The proposed sensor consisted of three coils, from which the primary was excited with an alternating current. In the space surrounded by the coils was a cell half-filled with ferrofluid, therefore in the horizontal state of the sensor the fluid distributes equally in the three sections of the cell surrounded by the three coils. Nevertheless when the cell is being tilted or accelerated (in the direction of the axis of the coils), there is a different amount of ferrofluid in the three sections. The voltage induced in the secondary coils strongly depends on the amount of ferrofluid found in the core surrounded by them, so the tilt or the acceleration of the cell becomes measurable. We constructed the sensor in several layouts. The linearly coiled sensor had an excellent resolution. Another version with a toroidal cell had almost perfect linearity and a virtually infinite measuring range. - Highlights: • A ferrofluid core differential transformer can be used to measure tilt. • The theoretical description of two different type of the sensor is introduced. • The measuring range, and the sensitivity depends on the dimensions of the sensor.

  5. Neutral wind measurements by Fabry-Perot interferometry in Antarctica

    International Nuclear Information System (INIS)

    Stewart, K.D.; Dudeney, J.R.; Rodger, A.S.; Smith, R.W.; Rees, D.

    1986-01-01

    A large-aperture (150 mm), spatially scanned Fabry-Perot Interferometer (FPI) has been deployed at Halley (75.5 o S, 26.8 o W; L=4.2), Antarctica. Thermospheric neutral wind measurements were made by finding the Doppler shift of the OI( 3 P 2 - 1 D 2 ) 630.0 nm emission. This has allowed the first comparison to be made between southern hemisphere ground-based thermospheric wind measurements and the predictions of a three-dimensional, time-dependent thermospheric global circulation model. Geomagnetic and geographic latitude are well separated at Halley, so we may expect a distinct contrast to the dynamic behaviour observed in the more frequently studied northern polar thermosphere. Although the initial results from the experiment are in general agreement with the model, some consistent and significant differences between the observed wind field and that predicted are evident in the morning sector. These may be related to uncertainties in mapping magnetospheric boundaries to ionospheric heights in the southern hemisphere. The intensity of the 630 nm emission has been examined with respect to the maximum plasma frequency of the Es layer using data from the Advanced Ionospheric Sounder at Halley

  6. Spatially Modeling the Impact of Terrain on Wind Speed and Dry Particle Deposition Across Lake Perris in Southern California to Determine In Situ Sensor Placement

    Science.gov (United States)

    Brooks, A. N.

    2014-12-01

    While developed countries have implemented engineering techniques and sanitation technologies to keep water resources clean from runoff and ground contamination, air pollution and its contribution of harmful contaminants to our water resources has yet to be fully understood and managed. Due to the large spatial and temporal extent and subsequent computational intensity required to understand atmospheric deposition as a pollutant source, a geographic information system (GIS) was utilized. This project developed a multi-step workflow to better define the placement of in situ sensors on Lake Perris in Southern California. Utilizing a variety of technologies including ArcGIS 10.1 with 3D and Spatial Analyst extensions and WindNinja, the impact of terrain on wind speed and direction was simulated and the spatial distribution of contaminant deposition across Lake Perris was calculated as flux. Specifically, the flux of particulate matter (PM10) at the air - water interface of a lake surface was quantified by season for the year of 2009. Integrated Surface Hourly (ISH) wind speed and direction data and ground station air quality measurements from the California Air Resources Board were processed and integrated for use within ModelBuilder. Results indicate that surface areas nearest Alessandro Island and the dam of Lake Perris should be avoided when placing in situ sensors. Furthermore, the location of sensor placement is dependent on seasonal fluctuations of PM10 which can be modeled using the techniques used in this study.

  7. Calorimetric sensors for energy deposition measurements

    International Nuclear Information System (INIS)

    Langenbrunner, J.; Cooper, R.; Morgan, G.

    1998-01-01

    A calorimetric sensor with several novel design features has been developed. These sensors will provide an accurate sampling of thermal power density and energy deposition from proton beams incident on target components of accelerator-based systems, such as the Accelerator Production of Tritium Project (APT) and the Spallation Neutron Source (SNS). A small, solid slug (volume = 0.347 cc) of target material is suspended by kevlar fibers and surrounded by an adiabatic enclosure in an insulating vacuum canister of stainless steel construction. The slug is in thermal contact with a low-mass, calibrated, 100-kΩ thermistor. Power deposition caused by the passage of radiation through the slug is calculated from the rate of temperature rise of the slug. The authors have chosen slugs composed of Pb, Al, and LiAl

  8. Isolated systems with wind power. Results of measurements in Egypt

    DEFF Research Database (Denmark)

    Bindner, Henrik W.; Saleh, L.; Hafiez, S.A.

    2001-01-01

    different sites. Three of the sites were in Hurghada, where the power system is rather large. The last two measurement sites were at village systems: one large system and one with only power ca. five hours perday. The measured load profiles were quite different at the different sites. The power quality...... at the different sites was adequate even at the small village sites where the load is almost constant. The impact of different load profiles on the technicaland economic performance of a wind diesel system in the feasibility phase was investigated. The results indicate that when the profile has low values...

  9. An Optical Fiber Bundle Sensor for Tip Clearance and Tip Timing Measurements in a Turbine Rig

    Directory of Open Access Journals (Sweden)

    María Asunción Illarramendi

    2013-06-01

    Full Text Available When it comes to measuring blade-tip clearance or blade-tip timing in turbines, reflective intensity-modulated optical fiber sensors overcome several traditional limitations of capacitive, inductive or discharging probe sensors. This paper presents the signals and results corresponding to the third stage of a multistage turbine rig, obtained from a transonic wind-tunnel test. The probe is based on a trifurcated bundle of optical fibers that is mounted on the turbine casing. To eliminate the influence of light source intensity variations and blade surface reflectivity, the sensing principle is based on the quotient of the voltages obtained from the two receiving bundle legs. A discrepancy lower than 3% with respect to a commercial sensor was observed in tip clearance measurements. Regarding tip timing measurements, the travel wave spectrum was obtained, which provides the average vibration amplitude for all blades at a particular nodal diameter. With this approach, both blade-tip timing and tip clearance measurements can be carried out simultaneously. The results obtained on the test turbine rig demonstrate the suitability and reliability of the type of sensor used, and suggest the possibility of performing these measurements in real turbines under real working conditions.

  10. Wind reconstruction algorithm for Viking Lander 1

    Science.gov (United States)

    Kynkäänniemi, Tuomas; Kemppinen, Osku; Harri, Ari-Matti; Schmidt, Walter

    2017-06-01

    The wind measurement sensors of Viking Lander 1 (VL1) were only fully operational for the first 45 sols of the mission. We have developed an algorithm for reconstructing the wind measurement data after the wind measurement sensor failures. The algorithm for wind reconstruction enables the processing of wind data during the complete VL1 mission. The heater element of the quadrant sensor, which provided auxiliary measurement for wind direction, failed during the 45th sol of the VL1 mission. Additionally, one of the wind sensors of VL1 broke down during sol 378. Regardless of the failures, it was still possible to reconstruct the wind measurement data, because the failed components of the sensors did not prevent the determination of the wind direction and speed, as some of the components of the wind measurement setup remained intact for the complete mission. This article concentrates on presenting the wind reconstruction algorithm and methods for validating the operation of the algorithm. The algorithm enables the reconstruction of wind measurements for the complete VL1 mission. The amount of available sols is extended from 350 to 2245 sols.

  11. Wind reconstruction algorithm for Viking Lander 1

    Directory of Open Access Journals (Sweden)

    T. Kynkäänniemi

    2017-06-01

    Full Text Available The wind measurement sensors of Viking Lander 1 (VL1 were only fully operational for the first 45 sols of the mission. We have developed an algorithm for reconstructing the wind measurement data after the wind measurement sensor failures. The algorithm for wind reconstruction enables the processing of wind data during the complete VL1 mission. The heater element of the quadrant sensor, which provided auxiliary measurement for wind direction, failed during the 45th sol of the VL1 mission. Additionally, one of the wind sensors of VL1 broke down during sol 378. Regardless of the failures, it was still possible to reconstruct the wind measurement data, because the failed components of the sensors did not prevent the determination of the wind direction and speed, as some of the components of the wind measurement setup remained intact for the complete mission. This article concentrates on presenting the wind reconstruction algorithm and methods for validating the operation of the algorithm. The algorithm enables the reconstruction of wind measurements for the complete VL1 mission. The amount of available sols is extended from 350 to 2245 sols.

  12. Auditory evoked field measurement using magneto-impedance sensors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, K., E-mail: o-kabou@echo.nuee.nagoya-u.ac.jp; Tajima, S.; Song, D.; Uchiyama, T. [Graduate School of Engineering, Nagoya University, Nagoya (Japan); Hamada, N.; Cai, C. [Aichi Steel Corporation, Tokai (Japan)

    2015-05-07

    The magnetic field of the human brain is extremely weak, and it is mostly measured and monitored in the magnetoencephalography method using superconducting quantum interference devices. In this study, in order to measure the weak magnetic field of the brain, we constructed a Magneto-Impedance sensor (MI sensor) system that can cancel out the background noise without any magnetic shield. Based on our previous studies of brain wave measurements, we used two MI sensors in this system for monitoring both cerebral hemispheres. In this study, we recorded and compared the auditory evoked field signals of the subject, including the N100 (or N1) and the P300 (or P3) brain waves. The results suggest that the MI sensor can be applied to brain activity measurement.

  13. Miniature Sensor for Aerosol Mass Measurements, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR project seeks to develop a miniature sensor for mass measurement of size-classified aerosols. A cascade impactor will be used to classify aerosol sample...

  14. Fiber optic micro sensor for the measurement of tendon forces

    Directory of Open Access Journals (Sweden)

    Behrmann Gregory P

    2012-10-01

    Full Text Available Abstract A fiber optic sensor developed for the measurement of tendon forces was designed, numerically modeled, fabricated, and experimentally evaluated. The sensor incorporated fiber Bragg gratings and micro-fabricated stainless steel housings. A fiber Bragg grating is an optical device that is spectrally sensitive to axial strain. Stainless steel housings were designed to convert radial forces applied to the housing into axial forces that could be sensed by the fiber Bragg grating. The metal housings were fabricated by several methods including laser micromachining, swaging, and hydroforming. Designs are presented that allow for simultaneous temperature and force measurements as well as for simultaneous resolution of multi-axis forces. The sensor was experimentally evaluated by hydrostatic loading and in vitro testing. A commercial hydraulic burst tester was used to provide uniform pressures on the sensor in order to establish the linearity, repeatability, and accuracy characteristics of the sensor. The in vitro experiments were performed in excised tendon and in a dynamic gait simulator to simulate biological conditions. In both experimental conditions, the sensor was found to be a sensitive and reliable method for acquiring minimally invasive measurements of soft tissue forces. Our results suggest that this sensor will prove useful in a variety of biomechanical measurements.

  15. Fiber optic micro sensor for the measurement of tendon forces.

    Science.gov (United States)

    Behrmann, Gregory P; Hidler, Joseph; Mirotznik, Mark S

    2012-10-03

    A fiber optic sensor developed for the measurement of tendon forces was designed, numerically modeled, fabricated, and experimentally evaluated. The sensor incorporated fiber Bragg gratings and micro-fabricated stainless steel housings. A fiber Bragg grating is an optical device that is spectrally sensitive to axial strain. Stainless steel housings were designed to convert radial forces applied to the housing into axial forces that could be sensed by the fiber Bragg grating. The metal housings were fabricated by several methods including laser micromachining, swaging, and hydroforming. Designs are presented that allow for simultaneous temperature and force measurements as well as for simultaneous resolution of multi-axis forces.The sensor was experimentally evaluated by hydrostatic loading and in vitro testing. A commercial hydraulic burst tester was used to provide uniform pressures on the sensor in order to establish the linearity, repeatability, and accuracy characteristics of the sensor. The in vitro experiments were performed in excised tendon and in a dynamic gait simulator to simulate biological conditions. In both experimental conditions, the sensor was found to be a sensitive and reliable method for acquiring minimally invasive measurements of soft tissue forces. Our results suggest that this sensor will prove useful in a variety of biomechanical measurements.

  16. Sensor for thickness measurement of a liquid metal film

    International Nuclear Information System (INIS)

    Blanc, R.

    1984-04-01

    Description, calibration and measuring method of a sensor for the measure of thin liquid metal depths in a temperature range of 0-500 0 C and for shift frequencies from 0 to 100 Hz; these sensors are based on the principle of induction-coil impedance variation, as a function of the thickness of an electrical conductor matter placed in the coil magnetic field [fr

  17. Wind Gust Measurement Techniques—From Traditional Anemometry to New Possibilities

    Directory of Open Access Journals (Sweden)

    Irene Suomi

    2018-04-01

    Full Text Available Information on wind gusts is needed for assessment of wind-induced damage and risks to safety. The measurement of wind gust speed requires a high temporal resolution of the anemometer system, because the gust is defined as a short-duration (seconds maximum of the fluctuating wind speed. Until the digitalization of wind measurements in the 1990s, the wind gust measurements suffered from limited recording and data processing resources. Therefore, the majority of continuous wind gust records date back at most only by 30 years. Although the response characteristics of anemometer systems are good enough today, the traditional measurement techniques at weather stations based on cup and sonic anemometers are limited to heights and regions where the supporting structures can reach. Therefore, existing measurements are mainly concentrated over densely-populated land areas, whereas from remote locations, such as the marine Arctic, wind gust information is available only from sparse coastal locations. Recent developments of wind gust measurement techniques based on turbulence measurements from research aircraft and from Doppler lidar can potentially provide new information from heights and locations unreachable by traditional measurement techniques. Moreover, fast-developing measurement methods based on Unmanned Aircraft Systems (UASs may add to better coverage of wind gust measurements in the future. In this paper, we provide an overview of the history and the current status of anemometry from the perspective of wind gusts. Furthermore, a discussion on the potential future directions of wind gust measurement techniques is provided.

  18. Utgrunden off-shore wind farm - Measurements of underwater noise

    International Nuclear Information System (INIS)

    Lindell, Hans

    2003-07-01

    Airicole, GE Wind Energy and SEAS/Energi E2 have initiated this project in order to achieve a better understanding on how offshore based wind farms effect the underwater noise. The main reason is to gain knowledge on how marine wildlife could be effected by this kind of installation. The measurements were performed at Utgrunden wind farm that is situated at the reef Utgrunden on the Swedish southeast coast. The farm consists of seven 1,5 MW turbines. Three hydrophones registered the underwater sound and four accelerometers the tower vibrations. The measurement campaign was conducted during a period from November 2002 to February 2003. The objectives with this project is to answer the following issues and its results are: 1. What is the character of sound from a single power station? - The turbines radiate sound mainly at a few dominating frequencies from 30 Hz up to 800 Hz. At frequencies below 3 Hz no contribution from the turbines can be detected due to the high background level from the waves and the low tower vibration level. 2. What are the sound generating mechanisms in the turbine? - Gearbox mesh frequency vibrations that are transmitted via the tower structure and radiated out to the water mainly generate the sound. Airborne blade sound is effectively dampened in the transition from air to water. 3. How does the sound attenuate with increasing distance at different frequencies? - The average attenuation per doubled distance for frequencies between 31 Hz and 722 Hz is approximately 4 dB in the measured positions. No clear frequency dependence could be found. 4. How does the sound pressure level vary with increasing wind speed? - With increasing wind speed, the sound pressure level increases and the dominating frequencies move upward due to increasing turbine rotational speed. 5. How does sound from different power stations interfere with each other and influence the over all sound image? - No clear tendencies of interference could be observed in this study

  19. Lightning Current Measurement with Fiber-Optic Sensor

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

    2014-01-01

    A fiber-optic current sensor is successfully developed with many potential applications for electric current measurement. Originally developed for in-flight lightning measurement, the sensor utilizes Faraday Effect in an optical fiber. The Faraday Effect causes linear light polarization in a fiber to rotate when the fiber is exposed to a magnetic field. The polarization change is detected using a reflective polarimetric scheme. Forming fiber loops and applying Ampere's law, measuring the total light rotation results in the determination of the total current enclosed. The sensor is conformable to complex structure geometry. It is also non-conductive and immune to electromagnetic interference, saturation or hysteresis. Installation is non-intrusive, and the sensor can be safely routed through flammable areas. Two similar sensor systems are described in this paper. The first system operates at 1310nm laser wavelength and is capable of measuring approximately 300 A - 300 kA, a 60 dB range. Laboratory validation results of aircraft lighting direct and in-direct effect current amplitudes are reported for this sensor. The second system operates at 1550nm wavelength and can measure about 400 A - 400 kA. Triggered-lightning measurement data are presented for this system. Good results are achieved in all cases.

  20. A Vision-Based Sensor for Noncontact Structural Displacement Measurement

    Science.gov (United States)

    Feng, Dongming; Feng, Maria Q.; Ozer, Ekin; Fukuda, Yoshio

    2015-01-01

    Conventional displacement sensors have limitations in practical applications. This paper develops a vision sensor system for remote measurement of structural displacements. An advanced template matching algorithm, referred to as the upsampled cross correlation, is adopted and further developed into a software package for real-time displacement extraction from video images. By simply adjusting the upsampling factor, better subpixel resolution can be easily achieved to improve the measurement accuracy. The performance of the vision sensor is first evaluated through a laboratory shaking table test of a frame structure, in which the displacements at all the floors are measured by using one camera to track either high-contrast artificial targets or low-contrast natural targets on the structural surface such as bolts and nuts. Satisfactory agreements are observed between the displacements measured by the single camera and those measured by high-performance laser displacement sensors. Then field tests are carried out on a railway bridge and a pedestrian bridge, through which the accuracy of the vision sensor in both time and frequency domains is further confirmed in realistic field environments. Significant advantages of the noncontact vision sensor include its low cost, ease of operation, and flexibility to extract structural displacement at any point from a single measurement. PMID:26184197

  1. Development of Meandering Winding Magnetometer (MWM (Register Trademark)) Eddy Current Sensors for the Health Monitoring, Modeling and Damage Detection of High Temperature Composite Materials

    Science.gov (United States)

    Russell, Richard; Washabaugh, Andy; Sheiretov, Yanko; Martin, Christopher; Goldfine, Neil

    2011-01-01

    The increased use of high-temperature composite materials in modern and next generation aircraft and spacecraft have led to the need for improved nondestructive evaluation and health monitoring techniques. Such technologies are desirable to improve quality control, damage detection, stress evaluation and temperature measurement capabilities. Novel eddy current sensors and sensor arrays, such as Meandering Winding Magnetometers (MWMs) have provided alternate or complimentary techniques to ultrasound and thermography for both nondestructive evaluation (NDE) and structural health monitoring (SHM). This includes imaging of composite material quality, damage detection and .the monitoring of fiber temperatures and multidirectional stresses. Historically, implementation of MWM technology for the inspection of the Space Shuttle Orbiter Reinforced Carbon-Carbon Composite (RCC) leading edge panels was developed by JENTEK Sensors and was subsequently transitioned by NASA as an operational pre and post flight in-situ inspection at the Kennedy Space Center. A manual scanner, which conformed'automatically to the curvature of the RCC panels was developed and used as a secondary technique if a defect was found during an infrared thermography screening, During a recent proof of concept study on composite overwrapped pressure vessels (COPV's), three different MWM sensors were tested at three orientations to demonstrate the ability of the technology to measure stresses at various fiber orientations and depths. These results showed excellent correlation with actual surface strain gage measurements. Recent advancements of this technology have been made applying MWM sensor technology for scanning COPVs for mechanical damage. This presentation will outline the recent advance in the MWM.technology and the development of MWM techniques for NDE and SHM of carbon wraped composite overwrapped pressure vessels (COPVs) including the measurement of internal stresses via a surface mounted sensor

  2. Acoustic sensor for remote measuring of pressure

    Directory of Open Access Journals (Sweden)

    Kataev V. F.

    2008-04-01

    Full Text Available The paper deals with sensors based on delay lines on surface acoustic waves (SAW, having a receiving-emitting and a reflective interdigital transducers (IDT. The dependence of the reflection coefficient of SAW on type and intensity of the load was studied. The authors propose a composite delay line in which the phase of the reflection coefficient depends on the pressure. Pressure leads to a shift of the reflective IDT relative to the transceiver, because they are located on different substrates. The paper also presents functional diagrams of the interrogator.

  3. Measurement system for special surface mapping using miniature displacement sensors

    Directory of Open Access Journals (Sweden)

    Zowade Martyna

    2018-01-01

    Full Text Available The aim of the work was to design a special system for measurements of elements with repetitive geometry or assemblies with repeating components, set in a linear patterns. The main focus was based on developing a computer program for signal analysis from variable number of miniature displacement sensors. It was set that the response for displacement of measuring tip from each sensor was a 0-5 V voltage signal with possibility of using different type of sensors. Requirements were determined based on projected measurement method. A special design of sensor was made for testing the computer program. If the characteristics of the sensor is known, it is possible to compute the type A evaluation of uncertainty. The results are presented in XY chart on computer screen. The program allows the user to choose any number of the sensors and determine the distance between them. Also, the possibility of calibration of sensors’ set was provided. The test were conducted on a prototype handle for sensors, made on a 3D printer.

  4. Calibrating a novel multi-sensor physical activity measurement system

    International Nuclear Information System (INIS)

    John, D; Sasaki, J E; Howe, C A; Freedson, P S; Liu, S; Gao, R X; Staudenmayer, J

    2011-01-01

    Advancing the field of physical activity (PA) monitoring requires the development of innovative multi-sensor measurement systems that are feasible in the free-living environment. The use of novel analytical techniques to combine and process these multiple sensor signals is equally important. This paper describes a novel multi-sensor 'integrated PA measurement system' (IMS), the lab-based methodology used to calibrate the IMS, techniques used to predict multiple variables from the sensor signals, and proposes design changes to improve the feasibility of deploying the IMS in the free-living environment. The IMS consists of hip and wrist acceleration sensors, two piezoelectric respiration sensors on the torso, and an ultraviolet radiation sensor to obtain contextual information (indoors versus outdoors) of PA. During lab-based calibration of the IMS, data were collected on participants performing a PA routine consisting of seven different ambulatory and free-living activities while wearing a portable metabolic unit (criterion measure) and the IMS. Data analyses on the first 50 adult participants are presented. These analyses were used to determine if the IMS can be used to predict the variables of interest. Finally, physical modifications for the IMS that could enhance the feasibility of free-living use are proposed and refinement of the prediction techniques is discussed

  5. RF sensor for multiphase flow measurement through an oil pipeline

    Science.gov (United States)

    Wylie, S. R.; Shaw, A.; Al-Shamma'a, A. I.

    2006-08-01

    We have developed, in conjunction with Solartron ISA, an electromagnetic cavity resonator based sensor for multiphase flow measurement through an oil pipeline. This sensor is non-intrusive and transmits low power (10 mW) radio frequencies (RF) in the range of 100-350 MHz and detects the pipeline contents using resonant peaks captured instantaneously. The multiple resonances from each captured RF spectrum are analysed to determine the phase fractions in the pipeline. An industrial version of the sensor for a 102 mm (4 inch) diameter pipe has been constructed and results from this sensor are compared to those given by simulations performed using the electromagnetic high frequency structure simulator software package HFSS. This paper was presented at the 13th International Conference on Sensors and held in Chatham, Kent, on 6-7 September 2005.

  6. Sensors 4.0 – smart sensors and measurement technology enable Industry 4.0

    Directory of Open Access Journals (Sweden)

    A. Schütze

    2018-05-01

    Full Text Available Industrie 4.0 or the Industrial Internet of Things (IIoT are two terms for the current (revolution seen in industrial automation and control. Everything is getting smarter and data generated at all levels of the production process are used to improve product quality, flexibility, and productivity. This would not be possible without smart sensors, which generate the data and allow further functionality from self-monitoring and self-configuration to condition monitoring of complex processes. In analogy to Industry 4.0, the development of sensors has undergone distinctive stages culminating in today's smart sensors or Sensor 4.0. This paper briefly reviews the development of sensor technology over the last 2 centuries, highlights some of the potential that can be achieved with smart sensors and data evaluation, and discusses success requirements for future developments. In addition to magnetic sensor technologies which allow self-test and self-calibration and can contribute to many applications due to their wide spectrum of measured quantities, the paper discusses condition monitoring as a primary paradigm for introducing smart sensors and data analysis in manufacturing processes based on two projects performed in our group.

  7. Study on the influence of attitude angle on lidar wind measurement results

    Science.gov (United States)

    Han, Xiaochen; Dou, Peilin; Xue, Yangyang

    2017-11-01

    When carrying on wind profile measurement of offshore wind farm by shipborne Doppler lidar technique, the ship platform often produces motion response under the action of ocean environment load. In order to measure the performance of shipborne lidar, this paper takes two lidar wind measurement results as the research object, simulating the attitude of the ship in the ocean through the three degree of freedom platform, carrying on the synchronous observation test of the wind profile, giving an example of comparing the wind measurement data of two lidars, and carrying out the linear regression statistical analysis for all the experimental correlation data. The results show that the attitude angle will affect the precision of the lidar, The influence of attitude angle on the accuracy of lidar is uncertain. It is of great significance to the application of shipborne Doppler lidar wind measurement technology in the application of wind resources assessment in offshore wind power projects.

  8. Vertical wind velocity measurements using a five-hole probe with remotely piloted aircraft to study aerosol–cloud interactions

    Directory of Open Access Journals (Sweden)

    R. Calmer

    2018-05-01

    Full Text Available The importance of vertical wind velocities (in particular positive vertical wind velocities or updrafts in atmospheric science has motivated the need to deploy multi-hole probes developed for manned aircraft in small remotely piloted aircraft (RPA. In atmospheric research, lightweight RPAs ( <  2.5 kg are now able to accurately measure atmospheric wind vectors, even in a cloud, which provides essential observing tools for understanding aerosol–cloud interactions. The European project BACCHUS (impact of Biogenic versus Anthropogenic emissions on Clouds and Climate: towards a Holistic UnderStanding focuses on these specific interactions. In particular, vertical wind velocity at cloud base is a key parameter for studying aerosol–cloud interactions. To measure the three components of wind, a RPA is equipped with a five-hole probe, pressure sensors, and an inertial navigation system (INS. The five-hole probe is calibrated on a multi-axis platform, and the probe–INS system is validated in a wind tunnel. Once mounted on a RPA, power spectral density (PSD functions and turbulent kinetic energy (TKE derived from the five-hole probe are compared with sonic anemometers on a meteorological mast. During a BACCHUS field campaign at Mace Head Atmospheric Research Station (Ireland, a fleet of RPAs was deployed to profile the atmosphere and complement ground-based and satellite observations of physical and chemical properties of aerosols, clouds, and meteorological state parameters. The five-hole probe was flown on straight-and-level legs to measure vertical wind velocities within clouds. The vertical velocity measurements from the RPA are validated with vertical velocities derived from a ground-based cloud radar by showing that both measurements yield model-simulated cloud droplet number concentrations within 10 %. The updraft velocity distributions illustrate distinct relationships between vertical cloud fields in different meteorological

  9. Wind tunnel measurement of spray drift from on-off controlled sprayer nozzles

    DEFF Research Database (Denmark)

    Lund, Ivar; Jensen, Peter Kryger; Miller, Paul

    wide surface area with a length of 200 mm. The test was conducted in the wind tunnel at Silsoe Spray Applications Unit in the UK. The measurements consisted of two test series; airborne drift was collected on polyethylene lines more than 375 mm away from the centerline of the nozzle and ground deposits...... and arranged to deliver a pulse of spray using the WeedSeeker valve. The tests were conducted to determine accumulated spray deposit at different crosswind and forward speeds. In general, the deposits, especially those measured downwind close to the target zone showed significant increase as the crosswind......Sensor-based precision weed control system at a high resolution requires a high spray application accuracy to keep the spray in a small target zone. The objective of this research was to investigate the target accuracy and spray drift from individual controlled sprayer nozzles targeting a 250 mm...

  10. Some measurements of time and space correlation in wind tunnel

    Science.gov (United States)

    Favre, A; Gaviglio, J; Dumas, R

    1955-01-01

    Results are presented of research obtained by means of an apparatus for measurement of time and space correlation and of a spectral analyzer in the study of the longitudinal component of turbulence velocities in a wind tunnel downstream of a grid of meshes. Application to the case of a flat-plate boundary layer is illustrated. These researches were made at the Laboratoire de Mecanique de l'Atmosphere de l'I.M.F.M. for the O.N.E.R.A.

  11. Wind profiler mixing depth and entrainment measurements with chemical applications

    Energy Technology Data Exchange (ETDEWEB)

    Angevine, W.M.; Trainer, M.; Parrish, D.D.; Buhr, M.P.; Fehsenfeld, F.C. [NOAA Aeronomy Lab., Boulder, CO (United States); Kok, G.L. [NCAR Research Aviation Facility, Boulder, CO (United States)

    1994-12-31

    Wind profiling radars operating at 915 MHz have been present at a number of regional air quality studies. The profilers can provide a continuous, accurate record of the depth of the convective mixed layer with good time resolution. Profilers also provide information about entrainment at the boundary layer top. Mixing depth data from several days of the Rural Oxidants in the Southern Environment II (ROSE II) study in Alabama in June, 1992 are presented. For several cases, chemical measurements from aircraft and ground-based instruments are shown to correspond to mixing depth and entrainment zone behavior observed by the profiler.

  12. A novel polarization interferometer for measuring upper atmospheric winds

    International Nuclear Information System (INIS)

    Ting-Kui, Mu; Chun-Min, Zhang

    2010-01-01

    A static polarization interferometer for measuring upper atmospheric winds is presented, based on two Savart plates with their optical axes perpendicular to each other. The principle and characteristics of the interferometer are described. The interferometer with a wide field of view can offer a stable benchmark optical path difference over a specified spectral region of 0.55–0.63 μm because there are no quarter wave plates. Since the instrument employs a straight line common-path configuration but without moving parts and slits, it is very compact, simple, inherently robust and has high throughput. The paper is limited to a theoretical analysis. (general)

  13. Simulation of the Impact of New Aircraft-and Satellite-based Ocean Surface Wind Measurements on Wind Analyses and Numerical Forecasts

    Science.gov (United States)

    Miller, TImothy; Atlas, Robert; Black, Peter; Chen, Shuyi; Jones, Linwood; Ruf, Chris; Uhlhorn, Eric; Gamache, John; Amarin, Ruba; El-Nimri, Salem; hide

    2010-01-01

    The Hurricane Imaging Radiometer (HIRAD) is a new airborne microwave remote sensor for hurricane observations that is currently under development by NASA Marshall Space Flight Center, NOAA Hurricane Research Division, the University of Central Florida and the University of Michigan. HIRAD is being designed to enhance the realtime airborne ocean surface winds observation capabilities of NOAA and USAF Weather Squadron hurricane hunter aircraft currently using the operational airborne Stepped Frequency Microwave Radiometer (SFMR). Unlike SFMR, which measures wind speed and rain rate along the ground track directly beneath the aircraft, HIRAD will provide images of the surface wind and rain field over a wide swath (approx. 3 x the aircraft altitude). The present paper describes a set of Observing System Simulation Experiments (OSSEs) in which measurements from the new instrument as well as those from existing instruments (air, surface, and space-based) are simulated from the output of a detailed numerical model, and those results are used to construct H*Wind analyses, a product of the Hurricane Research Division of NOAA s Atlantic Oceanographic and Meteorological Laboratory. Evaluations will be presented on the impact of the HIRAD instrument on H*Wind analyses, both in terms of adding it to the full suite of current measurements, as well as using it to replace instrument(s) that may not be functioning at the future time the HIRAD instrument is implemented. Also shown will be preliminary results of numerical weather prediction OSSEs in which the impact of the addition of HIRAD observations to the initial state on numerical forecasts of the hurricane intensity and structure is assessed.

  14. AMA Conferences 2015. SENSOR 2015. 17th international conference on sensors and measurement technology. IRS2 2015. 14th international conference on infrared sensors and systems. Proceedings

    International Nuclear Information System (INIS)

    2015-01-01

    This meeting paper contains presentations of two conferences: SENSOR 2015 and IRS 2 (= International conference on InfraRed Sensors and systems). The first part of SENSOR 2015 contains the following chapters: (A) SENSOR PRINCIPLES: A.1: Mechanical sensors; A.2: Optical sensors; A.3: Ultrasonic sensors; A.4: Microacoustic sensors; A.5: Magnetic sensors; A.6: Impedance sensors; A.7: Gas sensors; A.8: Flow sensors; A.9: Dimensional measurement; A.10: Temperature and humidity sensors; A.11: Chemosensors; A.12: Biosensors; A.13: Embedded sensors; A.14: Sensor-actuator systems; (B) SENSOR TECHNOLOGY: B.1: Sensor design; B.2: Numerical simulation of sensors; B.3: Sensor materials; B.4: MEMS technology; B.5: Micro-Nano-Integration; B.6: Packaging; B.7: Materials; B.8: Thin films; B.9: Sensor production; B.10: Sensor reliability; B.11: Calibration and testing; B.12: Optical fibre sensors. (C) SENSOR ELECTRONICS AND COMMUNICATION: C.1: Sensor electronics; C.2: Sensor networks; C.3: Wireless sensors; C.4: Sensor communication; C.5: Energy harvesting; C.6: Measuring systems; C.7: Embedded systems; C.8: Self-monitoring and diagnosis; (D) APPLICATIONS: D.1: Medical measuring technology; D.2: Ambient assisted living; D.3: Process measuring technology; D.4: Automotive; D.5: Sensors in energy technology; D.6: Production technology; D.7: Security technology; D.8: Smart home; D.9: Household technology. The second part with the contributions of the IRS 2 2015 is structured as follows: (E) INFRARED SENSORS: E.1: Photon detectors; E.2: Thermal detectors; E.3: Cooled detectors; E.4: Uncooled detectors; E.5: Sensor modules; E.6: Sensor packaging. (G) INFRARED SYSTEMS AND APPLICATIONS: G.1: Thermal imaging; G.2: Pyrometry / contactless temperature measurement; G.3: Gas analysis; G.4: Spectroscopy; G.5: Motion control and presence detection; G.6: Security and safety monitoring; G.7: Non-destructive testing; F: INFRARED SYSTEM COMPONENTS: F.1: Infrared optics; F.2: Optical modulators; F.3

  15. Piezo-sensor self-diagnostics using electrical impedance measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Park, G. H. (Gyu Hae); Farrar, C. R. (Charles R.); Rutherford, A. C. (Amanda C.); Robertson, A. N. (Amy N.)

    2004-01-01

    This paper present the piezoelectric sensor self-diagnostic procedure that performs in-situ monitoring of the operational status of piezoelectric materials (PZT) used for sensors and actuators in structural health monitoring (SHM) applications. The use of active-sensing piezoelectric materials has received considerable attention in the SHM community. A critical aspect of the piezoelectric active-sensing technologies is that usually large numbers of distributed sensors and actuators are needed to perform the required monitoring process. The sensor/actuator self-diagnostic procedure, where the sensors/actuators are confirmed to be functioning properly during operation, is therefore a critical component to successfully complete the SHM process and to minimize the false indication regarding the structural health. The basis of this procedure is to track the changes in the capacitive value of piezoelectric materials resulting from the sensor failure, which is manifested in the imaginary part of the measured electrical admittances. Furthermore, through the analytical and experimental investigation, it is confirmed that the bonding layer between the PZT and a host structure significantly contributes to the measured capacitive values. Therefore, by monitoring the imaginary part of the admittances, one can quantitatively assess the degradation of the mechanical/electrical properties of the PZT and its attachment to a host structure. This paper concludes with an experimental example to demonstrate the feasibility of the proposed sensor-diagnostic procedure.

  16. Using piezoelectric sensors for ultrasonic pulse velocity measurements in concrete

    International Nuclear Information System (INIS)

    Kee, Seong-Hoon; Zhu, Jinying

    2013-01-01

    The ultrasonic pulse velocity (UPV) test has been a widely used non-destructive testing method for concrete structures. However, the conventional UPV test has limitations in consistency of results and applicability in hard-to-access regions of structures. The authors explore the feasibility of embedded piezoelectric (PZT) sensors for ultrasonic measurements in concrete structures. Two PZT sensors were embedded in a reinforced concrete specimen. One sensor worked as an actuator driven by an ultrasonic pulse-receiver, and another sensor worked as a receiver. A series of ultrasonic tests were conducted to investigate the performance of the embedded sensors in crack-free concrete and concrete specimens having a surface-breaking crack under various external loadings. Signals measured by the embedded sensors show a broad bandwidth with a centre frequency around 80 kHz, and very good coherence in the frequency range from 30 to 180 kHz. Furthermore, experimental variability in ultrasonic pulse velocity and attenuation is substantially reduced compared to previously reported values from conventional UPV equipment. Findings from this study demonstrate that the embedded sensors have great potential as a low-cost solution for ultrasonic transducers for health monitoring of concrete in structures. (paper)

  17. Estimating the Wind Resource in Uttarakhand: Comparison of Dynamic Downscaling with Doppler Lidar Wind Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lundquist, J. K. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pukayastha, A. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Martin, C. [Univ. of Colorado, Boulder, CO (United States); Newsom, R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-03-01

    Previous estimates of the wind resources in Uttarakhand, India, suggest minimal wind resources in this region. To explore whether or not the complex terrain in fact provides localized regions of wind resource, the authors of this study employed a dynamic down scaling method with the Weather Research and Forecasting model, providing detailed estimates of winds at approximately 1 km resolution in the finest nested simulation.

  18. Design and Development of a Magneto-Optic Sensor for Magnetic Field Measurements

    Directory of Open Access Journals (Sweden)

    Sarbani CHAKRABORTY

    2015-01-01

    Full Text Available A magneto-optic sensor is developed using a Terbium Doped Glass (TDG element as a Faraday rotation sensor and optical fiber as light transmitting and receiving medium. Online LabView based application software is developed to process the sensor output. The system is used to sense the magnetic field of a DC motor field winding in industrial environment. The sensor output is compared with the magnetic flux density variation obtained with a calibrated Hall Magnetic sensor (Gauss Meter. A linear variation of sensor output over wide range of current passing through the field winding is obtained. Further the results show an improved sensitivity of magneto-optic sensor over the Hall sensor.

  19. Accounting for the speed shear in wind turbine power performance measurement

    DEFF Research Database (Denmark)

    Wagner, Rozenn; Courtney, Michael; Gottschall, Julia

    2011-01-01

    The current IEC standard for wind turbine power performance measurement only requires measurement of the wind speed at hub height assuming this wind speed to be representative for the whole rotor swept area. However, the power output of a wind turbine depends on the kinetic energy flux, which...... itself depends on the wind speed profile, especially for large turbines. Therefore, it is important to characterize the wind profile in front of the turbine, and this should be preferably achieved by measuring the wind speed over the vertical range between lower and higher rotor tips. In this paper, we...... describe an experiment in which wind speed profiles were measured in front of a multimegawatt turbine using a ground–based pulsed lidar. Ignoring the vertical shear was shown to overestimate the kinetic energy flux of these profiles, in particular for those deviating significantly from a power law profile...

  20. Hybrid integrated sensor for position measurement

    International Nuclear Information System (INIS)

    Schmidt, B.; Schott, H.; Just, H.-J.

    1986-01-01

    The design, fabrication and performance of an integrated two-dimensional position sensitive photodetector are presented. The optoelectronic device used as sensitive element in the circuit is a full area position sensitive photodiode (PPD) with high linearity over the full sensitive area. The PPD is integrated with the analog electronics in a hybrid circuit using thick film technology. The analog electronics includes the signal amplification and the signal conditioning to form the output signals proportional to the light beam center position at the sensor surface and an output signal proportional to the light beam intensity. Using hybrid integration a new position sensitive transducer is developed giving output signals, transmiting in large distances without problems and driving directly actuators in any control system

  1. A miniature sensor for electrical field measurements in dusty planetary atmospheres

    International Nuclear Information System (INIS)

    Renno, N O; Rogacki, S; Kok, J F; Kirkham, H

    2008-01-01

    Dusty phenomena such as regular wind-blown dust, dust storms, and dust devils are the most important, currently active, geological processes on Mars. Electric fields larger than 100 kV/m have been measured in terrestrial dusty phenomena. Theoretical calculations predict that, close to the surface, the bulk electric fields in martian dusty phenomena reach the breakdown value of the isolating properties of thin martian air of about a few 10 kV/m. The fact that martian dusty phenomena are electrically active has important implications for dust lifting and atmospheric chemistry. Electric field sensors are usually grounded and distort the electric fields in their vicinity. Grounded sensors also produce large errors when subject to ion currents or impacts from clouds of charged particles. Moreover, they are incapable of providing information about the direction of the electric field, an important quantity. Finally, typical sensors with more than 10 cm of diameter are not capable of measuring electric fields at distances as small as a few cm from the surface. Measurements this close to the surface are necessary for studies of the effects of electric fields on dust lifting. To overcome these shortcomings, we developed the miniature electric-field sensor described in this article.

  2. Advanced haptic sensor for measuring human skin conditions

    Science.gov (United States)

    Tsuchimi, Daisuke; Okuyama, Takeshi; Tanaka, Mami

    2010-01-01

    This paper is concerned with the development of a tactile sensor using PVDF (Polyvinylidene Fluoride) film as a sensory receptor of the sensor to evaluate softness, smoothness, and stickiness of human skin. Tactile sense is the most important sense in the sensation receptor of the human body along with eyesight, and we can examine skin condition quickly using these sense. But, its subjectivity and ambiguity make it difficult to quantify skin conditions. Therefore, development of measurement device which can evaluate skin conditions easily and objectively is demanded by dermatologists, cosmetic industries, and so on. In this paper, an advanced haptic sensor system that can measure multiple information of skin condition in various parts of human body is developed. The applications of the sensor system to evaluate softness, smoothness, and stickiness of skin are investigated through two experiments.

  3. Inspection and Reconstruction of Metal-Roof Deformation under Wind Pressure Based on Bend Sensors

    OpenAIRE

    Yang, Liman; Cui, Langfu; Li, Yunhua; An, Chao

    2017-01-01

    Metal roof sheathings are widely employed in large-span buildings because of their light weight, high strength and corrosion resistance. However, their severe working environment may lead to deformation, leakage and wind-lift, etc. Thus, predicting these damages in advance and taking maintenance measures accordingly has become important to avoid economic losses and personal injuries. Conventionally, the health monitoring of metal roofs mainly relies on manual inspection, which unavoidably com...

  4. Videometric research on deformation measurement of large-scale wind turbine blades

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Utilization of wind energy is a promising way to generate power,and wind turbine blades play a key role in collecting the wind energy effectively.This paper attempts to measure the deformation parameter of wind turbine blades in mechanics experiments using a videometric method. In view that the blades experience small buckling deformation and large integral deformation simultaneously, we proposed a parallel network measurement(PNM) method including the key techniques such as camera network construction,c...

  5. Using Particle Image Velocimetry to Measure the Wind in a Winnowing Chamber

    OpenAIRE

    Matsui, Masami; Inoue, Eiji; Kuwano, Tomoko; Mori, Ken; Furuno, Yuko

    2003-01-01

    The array of vectors for the winnowing wind in the threshing unit was investigated uding PIV in order to improve the winnowing accuracy. It is difficult to measure wind velocities at many points simultaneously using the anemometer. However, visualization of the winnowing wind was possible using the tracer and laser beam. Futhermore, The PIV method made it possible to measure an array of vectors for the winnowing wind. The results produced by PIV concurred with the results of conventional meth...

  6. Passive and Self-Powered Autonomous Sensors for Remote Measurements

    Directory of Open Access Journals (Sweden)

    Mauro Serpelloni

    2009-02-01

    Full Text Available Autonomous sensors play a very important role in the environmental, structural, and medical fields. The use of this kind of systems can be expanded for several applications, for example in implantable devices inside the human body where it is impossible to use wires. Furthermore, they enable measurements in harsh or hermetic environments, such as under extreme heat, cold, humidity or corrosive conditions. The use of batteries as a power supply for these devices represents one solution, but the size, and sometimes the cost and unwanted maintenance burdens of replacement are important drawbacks. In this paper passive and self-powered autonomous sensors for harsh or hermetical environments without batteries are discussed. Their general architectures are presented. Sensing strategies, communication techniques and power management are analyzed. Then, general building blocks of an autonomous sensor are presented and the design guidelines that such a system must follow are given. Furthermore, this paper reports different proposed applications of autonomous sensors applied in harsh or hermetic environments: two examples of passive autonomous sensors that use telemetric communication are proposed, the first one for humidity measurements and the second for high temperatures. Other examples of self-powered autonomous sensors that use a power harvesting system from electromagnetic fields are proposed for temperature measurements and for airflow speeds.

  7. Passive and self-powered autonomous sensors for remote measurements.

    Science.gov (United States)

    Sardini, Emilio; Serpelloni, Mauro

    2009-01-01

    Autonomous sensors play a very important role in the environmental, structural, and medical fields. The use of this kind of systems can be expanded for several applications, for example in implantable devices inside the human body where it is impossible to use wires. Furthermore, they enable measurements in harsh or hermetic environments, such as under extreme heat, cold, humidity or corrosive conditions. The use of batteries as a power supply for these devices represents one solution, but the size, and sometimes the cost and unwanted maintenance burdens of replacement are important drawbacks. In this paper passive and self-powered autonomous sensors for harsh or hermetical environments without batteries are discussed. Their general architectures are presented. Sensing strategies, communication techniques and power management are analyzed. Then, general building blocks of an autonomous sensor are presented and the design guidelines that such a system must follow are given. Furthermore, this paper reports different proposed applications of autonomous sensors applied in harsh or hermetic environments: two examples of passive autonomous sensors that use telemetric communication are proposed, the first one for humidity measurements and the second for high temperatures. Other examples of self-powered autonomous sensors that use a power harvesting system from electromagnetic fields are proposed for temperature measurements and for airflow speeds.

  8. Upgrading the Arecibo Potassium Lidar Receiver for Meridional Wind Measurements

    Science.gov (United States)

    Piccone, A. N.; Lautenbach, J.

    2017-12-01

    Lidar can be used to measure a plethora of variables: temperature, density of metals, and wind. This REU project is focused on the set up of a semi steerable telescope that will allow the measurement of meridional wind in the mesosphere (80-105 km) with Arecibo Observatory's potassium resonance lidar. This includes the basic design concept of a steering system that is able to turn the telescope to a maximum of 40°, alignment of the mirror with the telescope frame to find the correct focusing, and the triggering and programming of a CCD camera. The CCD camera's purpose is twofold: looking though the telescope and matching the stars in the field of view with a star map to accurately calibrate the steering system and determining the laser beam properties and position. Using LabVIEW, the frames from the CCD camera can be analyzed to identify the most intense pixel in the image (and therefore the brightest point in the laser beam or stars) by plotting average pixel values per row and column and locating the peaks of these plots. The location of this pixel can then be plotted, determining the jitter in the laser and position within the field of view of the telescope.

  9. Fiber-Optic Sensor for Aircraft Lightning Current Measurement

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George G.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

    2012-01-01

    An electric current sensor based on Faraday rotation effect in optical fiber was developed for measuring aircraft lightning current. Compared to traditional sensors, the design has many advantages including the ability to measure total current and to conform to structure geometries. The sensor is also small, light weight, non-conducting, safe from interference, and free of hysteresis and saturation. Potential applications include characterization of lightning current waveforms, parameters and paths, and providing environmental data for aircraft certifications. In an optical fiber as the sensing medium, light polarization rotates when exposed to a magnetic field in the direction of light propagation. By forming closed fiber loops around a conductor and applying Ampere s law, measuring the total light rotation yields the enclosed current. A reflective polarimetric scheme is used, where polarization change is measured after the polarized light travels round-trip through the sensing fiber. The sensor system was evaluated measuring rocket-triggered lightning over the 2011 summer. Early results compared very well against a reference current shunt resistor, demonstrating the sensor s accuracy and feasibility in a lightning environment. While later comparisons show gradually increasing amplitude deviations for an undetermined cause, the overall waveforms still compared very well.

  10. Optical sensor for heat conduction measurement in biological tissue

    International Nuclear Information System (INIS)

    Gutierrez-Arroyo, A; Sanchez-Perez, C; Aleman-Garcia, N

    2013-01-01

    This paper presents the design of a heat flux sensor using an optical fiber system to measure heat conduction in biological tissues. This optoelectronic device is based on the photothermal beam deflection of a laser beam travelling in an acrylic slab this deflection is measured with a fiber optic angle sensor. We measure heat conduction in biological samples with high repeatability and sensitivity enough to detect differences in tissues from three chicken organs. This technique could provide important information of vital organ function as well as the detect modifications due to degenerative diseases or physical damage caused by medications or therapies.

  11. Exploring the nearshore marine wind profile from field measurements and numerical hindcast

    Science.gov (United States)

    del Jesus, F.; Menendez, M.; Guanche, R.; Losada, I.

    2012-12-01

    Wind power is the predominant offshore renewable energy resource. In the last years, offshore wind farms have become a technically feasible source of electrical power. The economic feasibility of offshore wind farms depends on the quality of the offshore wind conditions compared to that of onshore sites. Installation and maintenance costs must be balanced with more hours and a higher quality of the available resources. European offshore wind development has revealed that the optimum offshore sites are those in which the distance from the coast is limited with high available resource. Due to the growth in the height of the turbines and the complexity of the coast, with interactions between inland wind/coastal orography and ocean winds, there is a need for field measurements and validation of numerical models to understand the marine wind profile near the coast. Moreover, recent studies have pointed out that the logarithmic law describing the vertical wind profile presents limitations. The aim of this work is to characterize the nearshore vertical wind profile in the medium atmosphere boundary layer. Instrumental observations analyzed in this work come from the Idermar project (www.Idermar.es). Three floating masts deployed at different locations on the Cantabrian coast provide wind measurements from a height of 20 to 90 meters. Wind speed and direction are measured as well as several meteorological variables at different heights of the profile. The shortest wind time series has over one year of data. A 20 year high-resolution atmospheric hindcast, using the WRF-ARW model and focusing on hourly offshore wind fields, is also analyzed. Two datasets have been evaluated: a European reanalysis with a ~15 Km spatial resolution, and a hybrid downscaling of wind fields with a spatial resolution of one nautical mile over the northern coast of Spain.. These numerical hindcasts have been validated based on field measurement data. Several parameterizations of the vertical wind

  12. A FULL-SCALE MEASUREMENT OF WIND ACTIONS AND EFFECTS ON A SEA-CROSSING BRIDGE

    Directory of Open Access Journals (Sweden)

    Yi Zhou

    2017-10-01

    Full Text Available Wind loading is critical for the large-span and light-weight structures, and field measurement is the most effective way to evaluate the wind resistance performance of a specific structure. This study investigates the wind characteristics and wind-induced vibration on a sea-crossing bridge in China, namely Donghai Bridge, based on up to six years of monitoring data. It is found that: (1 there exists obvious discrepancy between the measured wind field parameters and the values suggested by the design code; and the wind records at the bridge site is easily interfered by the bridge structure itself, which should be considered in interpreting the measurements and designing structural health monitoring systems (SHMS; (2 for strong winds with high non-stationarity, a shorter averaging time than 10-min is preferable to obtain more stable turbulent wind characteristics; (3 the root mean square (RMS of the wind-induced acceleration of the girder may increase in an approximately quadratic curve relationship with the mean wind speed; and (4 compared to traffic load, the wind dominates the girder’s lateral vibration amplitude, while the heavy-load traffic might exert more influence on the girder’s vertical and torsional vibrations than the high winds. This study provides field evidence for the wind-resistant design and evaluation of bridges in similar operational conditions.

  13. Wind Turbine Performance Measurements by Means of Dynamic Data Analysis

    DEFF Research Database (Denmark)

    Friis Pedersen, Troels; Wagner, Rozenn; Demurtas, Giorgio

    tools have been developed by authors to try to make the drift field and fixed point determination more robust. A sensitivity analysis with nacelle lidar data showed drift determination was not very dependent on the time steps applied, leading to use of time steps of 2-3 points for each dataset. Power...... bin size should be fixed. Data averaging with 5 sec data was more distinct for determination of the fixed points than 2 and 1 sec data. With the nacelle lidar the Langevin method seemed to produce a power curve that was comparable to the IEC power curve. Analysis of the Langevin method with spinner...... curves could be made faster with 1Hz dataset. In the FastWind project the Langevin power curve method was used on real power curve measurement datasets with the purpose to evaluate the method for practical use. A practical guide to application of the method to real power curve measurement data was made...

  14. Frequency swept fibre laser for wind speed measurements

    DEFF Research Database (Denmark)

    Pedersen, Anders Tegtmeier

    This PhD thesis builds around a light source forming the basis for a novel type of wind measuring lidar. The lidar emits a train of laser pulses with each pulse being separated from its neighbours in frequency, while being closely spaced in time, thus combining the advantages of conventional...... continuous wave (CW) and pulsed lidars. A light source capable of emitting such a pulse train is suggested. A theoretical description of all components constituting the light source is presented, and a time dependent model is developed and compared to measurements as well as to previous theoretical work from...... the scientific literature. The model presented shows good agreement with the experimental results regarding the pulse train envelope as well as the individual pulses. A model adopted from the literature is subsequently expanded to incorporate frequency components other than the main signal frequency and compared...

  15. Limitations of temperature measurement in the aural canal with an ear mould integrated sensor

    International Nuclear Information System (INIS)

    Teunissen, L P J; Daanen, H A M; De Haan, A; De Koning, J J; Clairbois, H E

    2011-01-01

    Aural canal temperature measurement using an ear mould integrated sensor (T ac ) might be a method suited for continuous non-invasive core temperature estimation in operational settings. We studied the effect of ambient temperature, wind and high intensity exercise on T ac and its ability to predict esophageal (T es ) and rectal temperatures (T re ). Seven subjects performed a protocol of rest at 21, 10 and 30 °C, followed by exercise and recovery at 30 °C. The subjects performed the protocol twice: with and without face-wind from halfway through the 30 °C rest period. Extra auricle insulation was applied at one side. Ambient temperature changes affected T ac significantly, while T es and T re remained stable. Insulating the auricle reduced but did not abolish this effect. Wind had an immediate cooling effect on T ac independent of auricle insulation. During exercise and recovery in 30 °C, T ac provided acceptable group predictions of T re in trials without wind (bias: −0.66 ± 0.21 °C covered, −1.20 ± 0.15 °C uncovered). Bias was considerably higher with wind, but variability was similar (−1.73 ± 0.11 °C covered, −2.49 ± 0.04 °C uncovered). Individual predictions of T es and T re showed more variation, especially with wind. We conclude that T ac may be used for core temperature assessment of groups in warm and stable conditions

  16. Measuring intracellular redox conditions using GFP-based sensors

    DEFF Research Database (Denmark)

    Björnberg, Olof; Ostergaard, Henrik; Winther, Jakob R

    2006-01-01

    Recent years have seen the development of methods for analyzing the redox conditions in specific compartments in living cells. These methods are based on genetically encoded sensors comprising variants of Green Fluorescent Protein in which vicinal cysteine residues have been introduced at solvent......-exposed positions. Several mutant forms have been identified in which formation of a disulfide bond between these cysteine residues results in changes of their fluorescence properties. The redox sensors have been characterized biochemically and found to behave differently, both spectroscopically and in terms...... of redox properties. As genetically encoded sensors they can be expressed in living cells and used for analysis of intracellular redox conditions; however, which parameters are measured depends on how the sensors interact with various cellular redox components. Results of both biochemical and cell...

  17. Optical measurement of a micro coriolis mass flow sensor

    NARCIS (Netherlands)

    Kristiansen, L.; Mehendale, A.; Brouwer, Dannis Michel; Zwikker, J.M.; Klein, M.E.

    2009-01-01

    Haneveld [1,2] demonstrated a micro Coriolis mass flow sensor, operating in the measurement range of 0 to 1 g/hr achieving a resolution in the order of 10 mg/hr using a laser vibrometer. Equipped with an integrated capacitive [3] readout the measurement uncertainty amounted to 2% of the full scale

  18. Pirani pressure sensor with distributed temperature measurement

    NARCIS (Netherlands)

    de Jong, B.R.; Bula, W.P.; Zalewski, D.R.; van Baar, J.J.J.; Wiegerink, Remco J.

    2003-01-01

    Surface micro-machined distributed Pirani pressure gauges, with designed heater-to-heat sink distances (gap-heights) of 0.35 μm and 1.10 μm, are successfully fabricated, modeled and characterized. Measurements and model response correspond within 5% of the measured value in a pressure range of 10 to

  19. Capacitive sensor for engine oil deterioration measurement

    Science.gov (United States)

    Shinde, Harish; Bewoor, Anand

    2018-04-01

    A simple system or mechanism for engine Oil (lubricating oil) deterioration monitoring is a need. As engine oil is an important element in I C engines and it is exposed to various strains depending on the operating conditions. If it becomes contaminated with dirt and metal particles, it can become too thick or thin and loses its protective properties, leads to unwanted friction. In turn, to avoid an engine failure, the oil must be changed before it loses its protective properties, which may be harmful to engine which deteriorates vehicle performance. At the same time, changing the lubricant too early, cause inefficient use of already depleting resources, also unwanted impact on the environment and economic reasons. Hence, it will be always helpful to know the quality of the oil under use. With this objective, the research work had been undertaken to develop a simple capacitance sensor for quantification of the quality of oil under use. One of the investigated parameter to quantify oil degradation is Viscosity (as per standard testing procedure: DIN 51562-1). In this research work, an alternative method proposed which analyzing change in capacitance of oil, to quantify the quality of oil underuse and compared to a conventional standard method. The experimental results reported in this paper shows trend for the same. Engine oil of grade SAE 15W40 used for light-duty vehicle, vans and passenger cars is used for experimentation. Suggested method can form a base for further research to develop a cost-effective method for indicating the time to change in engine oil quality have been presented.

  20. Multidimensional measurement by using 3-D PMD sensors

    Directory of Open Access Journals (Sweden)

    T. Ringbeck

    2007-06-01

    Full Text Available Optical Time-of-Flight measurement gives the possibility to enhance 2-D sensors by adding a third dimension using the PMD principle. Various applications in the automotive (e.g. pedestrian safety, industrial, robotics and multimedia fields require robust three-dimensional data (Schwarte et al., 2000. These applications, however, all have different requirements in terms of resolution, speed, distance and target characteristics. PMDTechnologies has developed 3-D sensors based on standard CMOS processes that can provide an optimized solution for a wide field of applications combined with high integration and cost-effective production. These sensors are realized in various layout formats from single pixel solutions for basic applications to low, middle and high resolution matrices for applications requiring more detailed data. Pixel pitches ranging from 10 micrometer up to a 300 micrometer or larger can be realized and give the opportunity to optimize the sensor chip depending on the application.

    One aspect of all optical sensors based on a time-of-flight principle is the necessity of handling background illumination. This can be achieved by various techniques, such as optical filters and active circuits on chip. The sensors' usage of the in-pixel so-called SBI-circuitry (suppression of background illumination makes it even possible to overcome the effects of bright ambient light. This paper focuses on this technical requirement. In Sect. 2 we will roughly describe the basic operation principle of PMD sensors. The technical challenges related to the system characteristics of an active optical ranging technique are described in Sect. 3, technical solutions and measurement results are then presented in Sect. 4. We finish this work with an overview of actual PMD sensors and their key parameters (Sect. 5 and some concluding remarks in Sect. 6.

  1. Electric field measurements with electro-optical sensor

    International Nuclear Information System (INIS)

    Brambilla, R.

    1992-03-01

    When electric field calculations on the surface of electrodes and electrical insulation present difficulties due to complex geometries and diverse dielectric properties, it is sometimes very useful to resort to direct measurements. However, conventional probes, based on the capacitive effect, are not quite suitable for this purpose due to strong perturbations introduced by probes themselves and to difficulties in isolating the sensors from the instrumentation at points of measurement with a high potential. To avoid these difficulties, a measurement system was developed which incorporates a Pockels effect crystal sensor, a moveable HeNe laser beam for signal transmission and beam polarization modulation, and a laser beam analyzer which detects variations in polarization induced by the sensor. This paper describes the key design, operation and performance characteristics of this device

  2. Pulsed electric field sensor based on original waveform measurement

    International Nuclear Information System (INIS)

    Ma Liang; Wu Wei; Cheng Yinhui; Zhou Hui; Li Baozhong; Li Jinxi; Zhu Meng

    2010-01-01

    The paper introduces the differential and original waveform measurement principles for pulsed E-field, and develops an pulsed E-field sensor based on original waveform measurement along with its theoretical correction model. The sensor consists of antenna, integrator, amplifier and driver, optic-electric/electric-optic conversion module and transmission module. The time-domain calibration in TEM cell indicates that, its risetime response is shorter than 1.0 ns, and the output pulse width at 90% of the maximum amplitude is wider than 10.0 μs. The output amplitude of the sensor is linear to the electric field intensity in a dynamic range of 20 dB. The measurement capability can be extended to 10 V/m or 50 kV/m by changing the system's antenna and other relative modules. (authors)

  3. A quartz crystal microbalance dew point sensor without frequency measurement

    Science.gov (United States)

    Wang, Guohua; Zhang, Weishuo; Wang, Shuo; Sun, Jinglin

    2014-11-01

    This work deals with the design of a dew point sensor based on Quartz Crystal Microbalance (QCM) without measuring the frequency. This idea is inspired by the fact that the Colpitts oscillation circuit will stop oscillating when the QCM works in the liquid media. The quartz crystal and the electrode are designed through the finite element simulation and the stop oscillating experiment is conducted to verify the sensibility. Moreover, the measurement result is calibrated to approach the true value. At last a series of dew points at the same temperature is measured with the designed sensor. Results show that the designed dew point sensor is able to detect the dew point with the proper accuracy.

  4. Photoplethysmographic sensors for perfusion measurements in spinal cord tissue

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, J P; Kyriacou, P A, E-mail: Justin.Phillips.1@city.ac.uk [School of Engineering and Mathematical Sciences, City University London, EC1V 0HB (United Kingdom)

    2011-08-17

    Sensors for recording photoplethysmographic signals from the nervous tissue of the spinal cord are described. The purpose of these sensors is to establish whether perfusion is compromised in various states of injury which occur in certain animal models of spinal cord injury, for example compression injury. Various measures of perfusion are applicable such as the amplitude of the photoplethysmograph signal and the oxygen saturation, measured using a dual wavelength configuration. Signals are usually compared to baseline measurements made in uninjured subjects. This paper describes two types of probe, one based on optical fibres, and one in which optotes are placed in direct contact with the tissue surface. Results from a study based on a compression model utilising a fibreoptic sensor are presented.

  5. Advances in measuring ocean salinity with an optical sensor

    International Nuclear Information System (INIS)

    Menn, M Le; De Bougrenet de la Tocnaye, J L; Grosso, P; Delauney, L; Podeur, C; Brault, P; Guillerme, O

    2011-01-01

    Absolute salinity measurement of seawater has become a key issue in thermodynamic models of the oceans. One of the most direct ways is to measure the seawater refractive index which is related to density and can therefore be related to the absolute salinity. Recent advances in high resolution position sensitive devices enable us to take advantage of small beam deviation measurements using refractometers. This paper assesses the advantages of such technology with respect to the current state-of-the-art technology. In particular, we present the resolution dependence on refractive index variations and derive the limits of such a solution for designing seawater sensors well suited for coastal and deep-sea applications. Particular attention has been paid to investigate the impact of environmental parameters, such as temperature and pressure, on an optical sensor, and ways to mitigate or compensate them have been suggested here. The sensor has been successfully tested in a pressure tank and in open oceans 2000 m deep

  6. Comparison of Flight Measured, Predicted and Wind Tunnel Measured Winglet Characteristics on a KC-135 Aircraft

    Science.gov (United States)

    Dodson, R. O., Jr.

    1982-01-01

    One of the objectives of the KC-135 Winglet Flight Research and Demonstration Program was to obtain experimental flight test data to verify the theoretical and wind tunnel winglet aerodynamic performance prediction methods. Good agreement between analytic, wind tunnel and flight test performance was obtained when the known differences between the tests and analyses were accounted for. The flight test measured fuel mileage improvements for a 0.78 Mach number was 3.1 percent at 8 x 10(5) pounds W/delta and 5.5 percent at 1.05 x 10(6) pounds W/delta. Correcting the flight measured data for surface pressure differences between wind tunnel and flight resulted in a fuel mileage improvement of 4.4 percent at 8 x 10(5) pounds W/delta and 7.2 percent at 1.05 x 10(6) pounds W/delta. The performance improvement obtained was within the wind tunnel test data obtained from two different wind tunnel models. The buffet boundary data obtained for the baseline configuration was in good agreement with previous established data. Buffet data for the 15 deg cant/-4 deg incidence configuration showed a slight improvement, while the 15 deg cant/-2 deg incidence and 0 deg cant/-4 deg incidence data showed a slight deterioration.

  7. Complete methodology on generating realistic wind speed profiles based on measurements

    DEFF Research Database (Denmark)

    Gavriluta, Catalin; Spataru, Sergiu; Mosincat, Ioan

    2012-01-01

    , wind modelling for medium and large time scales is poorly treated in the present literature. This paper presents methods for generating realistic wind speed profiles based on real measurements. The wind speed profile is divided in a low- frequency component (describing long term variations...

  8. Comparison of Large Eddy Simulations of a convective boundary layer with wind LIDAR measurements

    DEFF Research Database (Denmark)

    Pedersen, Jesper Grønnegaard; Kelly, Mark C.; Gryning, Sven-Erik

    2012-01-01

    Vertical profiles of the horizontal wind speed and of the standard deviation of vertical wind speed from Large Eddy Simulations of a convective atmospheric boundary layer are compared to wind LIDAR measurements up to 1400 m. Fair agreement regarding both types of profiles is observed only when...

  9. European wind turbine testing procedure developments. Task 1: Measurement method to verify wind turbine performance characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, R.; Friis Pedersen, T.; Dunbabin, P.; Antoniou, I.; Frandsen, S.; Klug, H.; Albers, A.; Lee, W.K.

    2001-01-01

    There is currently significant standardisation work ongoing in the context of wind farm energy yield warranty assessment and wind turbine power performance testing. A standards maintenance team is revising the current IEC (EN) 61400-12 Ed 1 standard for wind turbine power performance testing. The standard is being divided into four documents. Two of them are drafted for evaluation and verification of complete wind farms and of individual wind turbines within wind farms. This document, and the project it describes, has been designed to help provide a solid technical foundation for this revised standard. The work was wide ranging and addressed 'grey' areas of knowledge, regarding existing methodologies or to carry out basic research in support of fundamentally new procedures. The work has given rise to recommendations in all areas of the work, including site calibration procedures, nacelle anemometry, multi-variate regression analysis and density normalisation. (au)

  10. Results from a three-month intercomparison of boundary-layer wind profiler and sodar wind measurements at Lindenberg, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Beyrich, F.; Goersdorf, U.; Neisser, J.; Steinhagen, H.; Weisensee, U. [Deutscher Wetterdienst, Lindenberg (Germany). Meteorologisches Observatorium

    1998-10-01

    Intercomparison experiments with a wind profiler and a Doppler sodar have been performed at the meteorological observatory Lindenberg of the German weather service in summer, 1994, and in autumn, 1995, over a total period of about three months. The paper presents selected results of the wind measurements performed with the two systems. Sodar and wind profiler are shown to complement each other quite well. Therefore, a combination of both is a promising tool for continuous, high-resolution measurements of the wind profile. A problem to be solved is the construction of composite wind profiles when the measurements with the two systems disagree in the height range of overlapping. Measurements of the vertical velocity are difficult to assess due to their small absolute values. Long-term averages of the vertical velocity show slightly negative values, especially for the wind profiler. However, similar signatures have been found in the vertical velocity time series during frontal passages or during well-developed convection. (orig.) 7 refs.

  11. Demonstration of synchronised scanning Lidar measurements of 2D velocity fields in a boundary-layer wind tunnel

    DEFF Research Database (Denmark)

    van Dooren, M F; Kühn, M.; Petrovic, V.

    2016-01-01

    This paper combines the currently relevant research methodologies of scaled wind turbine model experiments in wind tunnels with remote-sensing short-range WindScanner Lidar measurement technology. The wind tunnel of the Politecnico di Milano was equipped with three wind turbine models and two short...... compared to hot wire probe measurements commonly used in wind tunnels. This yielded goodness of fit coefficients of 0.969 and 0.902 for the 1 Hz averaged u- and v-components of the wind speed, respectively, validating the 2D measurement capability of the Lidar scanners. Subsequently, the measurement...... for accurately measuring small scale flow structures in a wind tunnel....

  12. Quantification of rain gauge measurement undercatch and wind speed correction

    Science.gov (United States)

    Pollock, Michael; Quinn, Paul; Dutton, Mark; Wilkinson, Mark

    2014-05-01

    Hydrological processes are adversely affected by systematic rain gauge inaccuracy due to wind induced undercatching. The implications of this are discussed and addressed. Despite evidence of the undercatch problem being cited in the past and the difficulty in solving such a complex problem; it has become an inconvenient truth to hydrologists that major inaccuracies in rainfall measurement exist. A two year long experiment using new equipment and improved data logging and telemetery techniques enriches this formative work to redress the wilful neglect with which accurate rainfall measurement has been treated in recent decades. Results from this work suggest that the annual systematic undercatch can be in the order of 20 percent in the UK. During specific periods (measured at high temporal resolution), this can rise to as high as 50 percent for a single wind impacted event. As one organisation, responsible for the environment in the UK, moves towards using fewer instruments (15 percent fewer in the next year), it is scarcely possible to overstate the importance in solving this problem. It had been hoped that new equipment, such as acoustic distrometer and weighing gauge technologies, would be able to reduce the magnitude of the bias. However, through data gathered in the 2 year experiment and through secondary sources from the 1970s and 1980s, it is demonstrated that this is not the case and that the same problems with undercatching remain now as they did then. We further postulate that wider, denser networks of inexpensive telemetered equipment are now possible but they must still address the undercatch issue. There is little merit in pointing out an age old problem if no solution is put forward to fix it. The aforementioned experiment has furnished new ideas and further work has been commissioned to address this problem. This will be achieved via the medium of a Knowledge Transfer Partnership between Newcastle University and an innovative equipment manufacturer

  13. Rate of rotation measurement using back-EMFS associated with windings of a brushless DC motor

    Science.gov (United States)

    Howard, David E. (Inventor)

    2000-01-01

    A system and method are provided for measuring rate of rotation. A brushless DC motor is rotated and produces a back electromagnetic force (emf) on each winding thereof. Each winding's back-emf is integrated and multiplied by the back-emf associated with an adjacent winding. The multiplied outputs associated with each winding are combined to produce a directionally sensitive DC output proportional only to the rate of rotation of the motor's shaft.

  14. Griffon vulture mortality at wind farms in southern Spain: Distribution of fatalities and active mitigation measures

    OpenAIRE

    Lucas, Manuela de; Ferrer, Miguel; Bechard, Mark J.; Muñoz, Antonio R.

    2012-01-01

    Wind is increasingly being used as a renewable energy source around the world. Avian mortality is one of the negative impacts of wind energy and a new technique that reduces avian collision rates is necessary. Using the most frequently-killed species, the griffon vulture (Gyps fulvus), we studied its mortality at 13 wind farms in Tarifa, Cadiz, Spain, before (2006-2007) and after (2008-2009) when selective turbine stopping programs were implemented as a mitigation measure. Ten wind farms (tot...

  15. Measuring and modelling of the wind on the scale of tall wind turbines

    DEFF Research Database (Denmark)

    Floors, Rogier Ralph

    The air flow in the lower atmosphere on the spatial scale of the modern wind turbines is studied. Because wind turbines are nowadays often taller than 100 m, the validity of current analytical and numerical atmospheric models has to be evaluated and more knowledge about the structure of the atmos......The air flow in the lower atmosphere on the spatial scale of the modern wind turbines is studied. Because wind turbines are nowadays often taller than 100 m, the validity of current analytical and numerical atmospheric models has to be evaluated and more knowledge about the structure...

  16. Sensor Interaction as a Source of the Electromagnetic Field Measurement Error

    Directory of Open Access Journals (Sweden)

    Hartansky R.

    2014-12-01

    Full Text Available The article deals with analytical calculation and numerical simulation of interactive influence of electromagnetic sensors. Sensors are components of field probe, whereby their interactive influence causes the measuring error. Electromagnetic field probe contains three mutually perpendicular spaced sensors in order to measure the vector of electrical field. Error of sensors is enumerated with dependence on interactive position of sensors. Based on that, proposed were recommendations for electromagnetic field probe construction to minimize the sensor interaction and measuring error.

  17. Optical fibre sensor for the measurement of ozone

    International Nuclear Information System (INIS)

    O'Keeffe, S; Dooly, G; Fitzpatrick, C; Lewis, E

    2005-01-01

    The use of optical fibres for the measurement of ozone based on the optical absorption of both UV light at 254nm and visible light at 600nm is investigated and tested. Calculations based on the Beer-Lambert Law are also presented to demonstrate the high resolution of the UV based sensor in determining the concentration of ozone in the range of 0 mg/litre to 1mg/litre and the ability of the visible based sensor to measure high concentrations over a wide range

  18. Pollutant Plume Dispersion over Hypothetical Urban Areas based on Wind Tunnel Measurements

    Science.gov (United States)

    Mo, Ziwei; Liu, Chun-Ho

    2017-04-01

    Gaussian plume model is commonly adopted for pollutant concentration prediction in the atmospheric boundary layer (ABL). However, it has a number of limitations being applied to pollutant dispersion over complex land-surface morphology. In this study, the friction factor (f), as a measure of aerodynamic resistance induced by rough surfaces in the engineering community, was proposed to parameterize the vertical dispersion coefficient (σz) in the Gaussian model. A series of wind tunnel experiments were carried out to verify the mathematical hypothesis and to characterize plume dispersion as a function of surface roughness as well. Hypothetical urban areas, which were assembled in the form of idealized street canyons of different aspect (building-height-to-street-width) ratios (AR = 1/2, 1/4, 1/8 and 1/12), were fabricated by aligning identical square aluminum bars at different separation apart in cross flows. Pollutant emitted from a ground-level line source into the turbulent boundary layer (TBL) was simulated using water vapour generated by ultrasonic atomizer. The humidity and the velocity (mean and fluctuating components) were measured, respectively, by humidity sensors and hot-wire anemometry (HWA) with X-wire probes in streamwise and vertical directions. Wind tunnel results showed that the pollutant concentration exhibits the conventional Gaussian distribution, suggesting the feasibility of using water vapour as a passive scalar in wind tunnel experiments. The friction factor increased with decreasing aspect ratios (widening the building separation). It was peaked at AR = 1/8 and decreased thereafter. Besides, a positive correlation between σz/xn (x is the distance from the pollutant source) and f1/4 (correlation coefficient r2 = 0.61) was observed, formulating the basic parameterization of plume dispersion over urban areas.

  19. High Temperature Dynamic Pressure Measurements Using Silicon Carbide Pressure Sensors

    Science.gov (United States)

    Okojie, Robert S.; Meredith, Roger D.; Chang, Clarence T.; Savrun, Ender

    2014-01-01

    Un-cooled, MEMS-based silicon carbide (SiC) static pressure sensors were used for the first time to measure pressure perturbations at temperatures as high as 600 C during laboratory characterization, and subsequently evaluated in a combustor rig operated under various engine conditions to extract the frequencies that are associated with thermoacoustic instabilities. One SiC sensor was placed directly in the flow stream of the combustor rig while a benchmark commercial water-cooled piezoceramic dynamic pressure transducer was co-located axially but kept some distance away from the hot flow stream. In the combustor rig test, the SiC sensor detected thermoacoustic instabilities across a range of engine operating conditions, amplitude magnitude as low as 0.5 psi at 585 C, in good agreement with the benchmark piezoceramic sensor. The SiC sensor experienced low signal to noise ratio at higher temperature, primarily due to the fact that it was a static sensor with low sensitivity.

  20. Simulations of piezoelectric pressure sensor for radial artery pulse measurement

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Abhay B. [Department of Electronic Science, University of Pune, Pune 411 007 (India); Kalange, Ashok E. [Department of Electronic Science, University of Pune, Pune 411 007 (India); Tuljaram Chaturchand College, Baramati 413 102 (India); Bodas, Dhananjay, E-mail: dhananjay.bodas@gmail.co [Center for Nanobio Sciences, Agharkar Research Institute, Pune 411 004 (India); Gangal, S.A. [Department of Electronic Science, University of Pune, Pune 411 007 (India)

    2010-04-15

    A radial artery pulse is used to diagnose human body constitution (Prakruti) in Ayurveda. A system consisting of piezoelectric sensor (22 mm x 12 mm), data acquisition card and LabView software was used to record the pulse data. The pulse obtained from the sensor was noisy, even though signal processing was done. Moreover due to large sized senor accurate measurements were not possible. Hence, a need was felt to develop a sensor of the size of the order of finger tip with a resonant frequency of the order of 1 Hz. A micromachined pressure sensor based on piezoelectric sensing mechanism was designed and simulated using CoventorWare. Simulations were carried out by varying dimensions of the sensor to optimize the resonant frequency, stresses and voltage generated as a function of applied pressure. All simulations were done with pressure ranging of 1-30 kPa, which is the range used by Ayurvedic practitioners for diagnosis. Preliminary work on fabrication of such a sensor was carried out successfully.

  1. Simulations of piezoelectric pressure sensor for radial artery pulse measurement

    International Nuclear Information System (INIS)

    Joshi, Abhay B.; Kalange, Ashok E.; Bodas, Dhananjay; Gangal, S.A.

    2010-01-01

    A radial artery pulse is used to diagnose human body constitution (Prakruti) in Ayurveda. A system consisting of piezoelectric sensor (22 mm x 12 mm), data acquisition card and LabView software was used to record the pulse data. The pulse obtained from the sensor was noisy, even though signal processing was done. Moreover due to large sized senor accurate measurements were not possible. Hence, a need was felt to develop a sensor of the size of the order of finger tip with a resonant frequency of the order of 1 Hz. A micromachined pressure sensor based on piezoelectric sensing mechanism was designed and simulated using CoventorWare. Simulations were carried out by varying dimensions of the sensor to optimize the resonant frequency, stresses and voltage generated as a function of applied pressure. All simulations were done with pressure ranging of 1-30 kPa, which is the range used by Ayurvedic practitioners for diagnosis. Preliminary work on fabrication of such a sensor was carried out successfully.

  2. Advanced Load Alleviation for Wind Turbines using Adaptive Trailing Edge Flaps: Sensoring and Control

    DEFF Research Database (Denmark)

    Andersen, Peter Bjørn

    The purpose of wind turbines and their predecessors the windmill, is to convert the energy in the wind to usable energy forms. Whereas windmills of the past focused on the conversion of wind power to torque for grinding, pumping and winching, modern wind turbines convert the wind energy...... into electric power. They do so through incorporation of generators, which convert mechanical torque into electricity. Wind turbines are designed to keep the overall cost per produced Kilo Watt hour as low as possible. One way of improving the performance and lifetime of the wind turbine is through active flow...

  3. Measuring Dynamic Signals with Direct Sensor-to-Microcontroller Interfaces Applied to a Magnetoresistive Sensor

    Directory of Open Access Journals (Sweden)

    Ernesto Sifuentes

    2017-05-01

    Full Text Available This paper evaluates the performance of direct interface circuits (DIC, where the sensor is directly connected to a microcontroller, when a resistive sensor subjected to dynamic changes is measured. The theoretical analysis provides guidelines for the selection of the components taking into account both the desired resolution and the bandwidth of the input signal. Such an analysis reveals that there is a trade-off between the sampling frequency and the resolution of the measurement, and this depends on the selected value of the capacitor that forms the RC circuit together with the sensor resistance. This performance is then experimentally proved with a DIC measuring a magnetoresistive sensor exposed to a magnetic field of different frequencies, amplitudes, and waveforms. A sinusoidal magnetic field up to 1 kHz can be monitored with a resolution of eight bits and a sampling frequency of around 10 kSa/s. If a higher resolution is desired, the sampling frequency has to be lower, thus limiting the bandwidth of the dynamic signal under measurement. The DIC is also applied to measure an electrocardiogram-type signal and its QRS complex is well identified, which enables the estimation, for instance, of the heart rate.

  4. Measuring Dynamic Signals with Direct Sensor-to-Microcontroller Interfaces Applied to a Magnetoresistive Sensor.

    Science.gov (United States)

    Sifuentes, Ernesto; Gonzalez-Landaeta, Rafael; Cota-Ruiz, Juan; Reverter, Ferran

    2017-05-18

    This paper evaluates the performance of direct interface circuits (DIC), where the sensor is directly connected to a microcontroller, when a resistive sensor subjected to dynamic changes is measured. The theoretical analysis provides guidelines for the selection of the components taking into account both the desired resolution and the bandwidth of the input signal. Such an analysis reveals that there is a trade-off between the sampling frequency and the resolution of the measurement, and this depends on the selected value of the capacitor that forms the RC circuit together with the sensor resistance. This performance is then experimentally proved with a DIC measuring a magnetoresistive sensor exposed to a magnetic field of different frequencies, amplitudes, and waveforms. A sinusoidal magnetic field up to 1 kHz can be monitored with a resolution of eight bits and a sampling frequency of around 10 kSa/s. If a higher resolution is desired, the sampling frequency has to be lower, thus limiting the bandwidth of the dynamic signal under measurement. The DIC is also applied to measure an electrocardiogram-type signal and its QRS complex is well identified, which enables the estimation, for instance, of the heart rate.

  5. Fiber-optic evanescent-field sensor for attitude measurement

    Science.gov (United States)

    Liu, Yun; Chen, Shimeng; Liu, Zigeng; Guang, Jianye; Peng, Wei

    2017-11-01

    We proposed a new approach to attitude measurement by an evanescent field-based optical fiber sensing device and demonstrated a liquid pendulum. The device consisted of three fiber-optic evanescent-filed sensors which were fabricated by tapered single mode fibers and immersed in liquid. Three fiber Bragg gratings were used to measure the changes in evanescent field. And their reflection peaks were monitored in real time as measurement signals. Because every set of reflection responses corresponded to a unique attitude, the attitude of the device could be measured by the three fiber-optic evanescent-filed sensors. After theoretical analysis, computerized simulation and experimental verification, regular responses were obtained using this device for attitude measurement. The measurement ranges of dihedral angle and direction angle were 0°-50° and 0°-360°. The device is based on cost-effective power-referenced scheme. It can be used in electromagnetic or nuclear radiation environment.

  6. An MPC approach to individual pitch control of wind turbines using uncertain LIDAR measurements

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Soltani, Mohsen; Poulsen, Niels Kjølstad

    2013-01-01

    wind turbine in the full load region is considered. Model predictive control (MPC) is used to solve the problem. A new approach is proposed to simplify the optimization problem of MPC. We linearize the obtained nonlinear model for different operating points which are determined by the effective wind...... speed on the rotor disc and take the wind speed as a scheduling variable. The wind speed is measurable ahead of the turbine using LIDARs, therefore the scheduling variable is known for the entire prediction horizon. We consider uncertainty in the wind propagation, which is the traveling time of wind...... from the LIDAR measurement point to the rotor. An algorithm based on wind speed estimation and measurements from the LIDAR is devised to find an estimate of the delay and compensate for it before it is used in the controller. Comparisons between the MPC with error compensation, without error...

  7. Damage preventing measures for wind turbines. Phase 1- Reliability data

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Fredrik; Eriksson, Emil; Dahlberg, Magnus

    2010-08-15

    The state of existing reliability and failure data in the public sources has been investigated. The prime goal has been to evaluate the data's usefulness for developing damage preventing measures. Some publicly available databases exist, and the data has been presented in several papers in the literature. The results from the investigation can seem quite negative. Detailed data are lacking and the level of detailed reporting has even been decreasing in recent years. Information on the impact of load condition on failures, which is an important question, are lacking throughout in the statistics. Some components dominate the failure statistics. These are for example the gearboxes, where failures lead to long down times. Failures of the electrical system lead to considerably shorter down times but the failure rate is much higher. Severe rotor failures seem to be rare, but they occur and the consequences can be dramatic. Operators and insurance companies are demanding improved insight in damage collection, maintenance and overall damage preventing measures. Closer cooperation with these parties could be a fruitful way of gathering more useful data. Improvements for future databases are suggested. A structure for damage collection is proposed. Comparing experience of damage preventing measures from other industries, knowledge about the nature of the damage mechanism and current practice in the wind industry will be an important tool in the evaluation of different damage preventing measures. This will be done in the following phases of this project

  8. Multi-sensor measurement system for robotic drilling

    OpenAIRE

    Frommknecht, Andreas; Kühnle, Jens; Pidan, Sergej; Effenberger, Ira

    2015-01-01

    A multi-sensor measurement system for robotic drilling is presented. The system enables a robot to measure its 6D pose with respect to the work piece and to establish a reference coordinate system for drilling. The robot approaches the drill point and performs an orthogonal alignment with the work piece. Although the measurement systems are readily capable of achieving high position accuracy and low deviation to perpendicularity, experiments show that inaccuracies in the robot's 6D-pose and e...

  9. European wind turbine testing procedure developments. Task 1: Measurement method to verify wind turbine performance characteristics

    DEFF Research Database (Denmark)

    Hunter, R.; Friis Pedersen, Troels; Dunbabin, P.

    2001-01-01

    There is currently significant standardisation work ongoing in the context of wind farm energy yield warranty assessment and wind turbine power performance testing. A standards maintenance team is revising the current IEC (EN) 61400-12 Ed 1 standard forwind turbine power performance testing....... The standard is being divided into four documents. Two of them are drafted for evaluation and verification of complete wind farms and of individual wind turbines within wind farms. This document, and the project itdescribes, has been designed to help provide a solid technical foundation for this revised...... standard. The work was wide ranging and addressed 'grey' areas of knowledge, regarding existing methodologies or to carry out basic research in support offundamentally new procedures. The work has given rise to recommendations in all areas of the work, including site calibration procedures, nacelle...

  10. An Assessment of Wind Plant Complex Flows Using Advanced Doppler Radar Measurements

    Science.gov (United States)

    Gunter, W. S.; Schroeder, J.; Hirth, B.; Duncan, J.; Guynes, J.

    2015-12-01

    As installed wind energy capacity continues to steadily increase, the need for comprehensive measurements of wind plant complex flows to further reduce the cost of wind energy has been well advertised by the industry as a whole. Such measurements serve diverse perspectives including resource assessment, turbine inflow and power curve validation, wake and wind plant layout model verification, operations and maintenance, and the development of future advanced wind plant control schemes. While various measurement devices have been matured for wind energy applications (e.g. meteorological towers, LIDAR, SODAR), this presentation will focus on the use of advanced Doppler radar systems to observe the complex wind flows within and surrounding wind plants. Advanced Doppler radars can provide the combined advantage of a large analysis footprint (tens of square kilometers) with rapid data analysis updates (a few seconds to one minute) using both single- and dual-Doppler data collection methods. This presentation demonstrates the utility of measurements collected by the Texas Tech University Ka-band (TTUKa) radars to identify complex wind flows occurring within and nearby operational wind plants, and provide reliable forecasts of wind speeds and directions at given locations (i.e. turbine or instrumented tower sites) 45+ seconds in advance. Radar-derived wind maps reveal commonly observed features such as turbine wakes and turbine-to-turbine interaction, high momentum wind speed channels between turbine wakes, turbine array edge effects, transient boundary layer flow structures (such as wind streaks, frontal boundaries, etc.), and the impact of local terrain. Operational turbine or instrumented tower data are merged with the radar analysis to link the observed complex flow features to turbine and wind plant performance.

  11. Miniaturized diffraction based interferometric distance measurement sensor

    Science.gov (United States)

    Kim, Byungki

    In this thesis, new metrology hardware is designed, fabricated, and tested to provide improvements over current MEMS metrology. The metrology system is a micromachined scanning interferometer (muSI) having a sub-nm resolution in a compact design. The proposed microinterferometer forms a phase sensitive diffraction grating with interferomeric sensitivity, while adding the capability of better lateral resolution by focusing the laser to a smaller spot size. A detailed diffraction model of the microinterferometer was developed to simulate the device performance and to suggest the location of photo detectors for integrated optoelectronics. A particular device is fabricated on a fused silica substrate using aluminum to form the deformable diffraction grating fingers and AZ P4620 photo resist (PR) for the microlens. The details of the fabrication processes are presented. The structure also enables optoelectronics to be integrated so that the interferometer with photo detectors can fit in an area that is 1 mm x 1 mm. The scanning results using a fixed grating muSI demonstrated that it could measure vibration profile as well as static vertical (less than a half wave length) and lateral dimension of MEMS. The muSI, which is integrated with photo diodes, demonstrated its operation by scanning a cMUT. The PID control has been tested and resulted in improvement in scanned images. The integrated muSI demonstrated that the deformable grating could be used to tune the measurement keep the interferometer in quadrature for highest sensitivity.

  12. Characteristics of offshore extreme wind-waves detected by surface drifters with a low-cost GPS wave sensor

    Science.gov (United States)

    Komatsu, Kosei

    Wind-generated waves have been recognized as one of the most important factors of the sea surface roughness which plays crucial roles in various air-sea interactions such as energy, mo-mentum, heat and gas exchanges. At the same time, wind waves with extreme wave heights representatively called as freak or rogue waves have been a matter of great concern for many people involved in shipping, fishing, constracting, surfing and other marine activities, because such extreme waves frequently affect on the marine activities and sometimes cause serious dis-asters. Nevertheless, investigations of actual conditions for the evolution of wind waves in the offshore region are less and sparse in contrast to dense monitoring networks in the coastal re-gions because of difficulty of offshore observation with high accuracy. Recently accurate in situ observation of offshore wind waves is getting possible at low cost owing to a wave height and di-rection sensor developed by Harigae et al. (2004) by installing a point-positioning GPS receiver on a surface drifting buoy. The point-positioning GPS sensor can extract three dimensional movements of the buoy excited by ocean waves with minimizing effects of GPS point-positioning errors through the use of a high-pass filter. Two drifting buoys equipped with the GPS-based wave sensor charged by solar cells were drifted in the western North Pacific and one of them continued to observe wind waves during 16 months from Sep. 2007. The RMSE of the GPS-based wave sensor was less than 10cm in significant wave height and about 1s in significant wave period in comparison with other sensors, i.e. accelerometers installed on drifting buoys of Japan Meteorological Agency, ultrasonic sensors placed at the Hiratsuka observation station of the University of Tokyo and altimeter of the JASON-1. The GPS-based wave buoys enabled us to detect freak waves defined as waves whose height is more than twice the significant wave height. The observation conducted by

  13. Measurements in support of wind farm simulations and power forecasts: The Crop/Wind-energy Experiments (CWEX)

    International Nuclear Information System (INIS)

    Takle, E S; Rajewski, D A; Lundquist, J K; Gallus, W A Jr; Sharma, A

    2014-01-01

    The Midwest US currently is experiencing a large build-out of wind turbines in areas where the nocturnal low-level jet (NLLJ) is a prominent and frequently occurring feature. We describe shear characteristics of the NLLJ and their influence on wind power production. Reports of individual turbine power production and concurrent measurements of near-surface thermal stratification are used to turbine wake interactions and turbine interaction with the overlying atmosphere. Progress in forecasting conditions such as wind ramps and shear are discussed. Finally, the pressure perturbation introduced by a line of turbines produces surface flow convergence that may create a vertical velocity and hence a mesoscale influence on cloud formation by a wind farm

  14. A Sensor Management Tool for Use with NASA World Wind, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The number of sensors that are deployed continues to increase for scientific, commercial and intelligence related applications. Quantities of sensor data are...

  15. Evaluating anemometer drift: A statistical approach to correct biases in wind speed measurement

    Science.gov (United States)

    Azorin-Molina, Cesar; Asin, Jesus; McVicar, Tim R.; Minola, Lorenzo; Lopez-Moreno, Juan I.; Vicente-Serrano, Sergio M.; Chen, Deliang

    2018-05-01

    Recent studies on observed wind variability have revealed a decline (termed "stilling") of near-surface wind speed during the last 30-50 years over many mid-latitude terrestrial regions, particularly in the Northern Hemisphere. The well-known impact of cup anemometer drift (i.e., wear on the bearings) on the observed weakening of wind speed has been mentioned as a potential contributor to the declining trend. However, to date, no research has quantified its contribution to stilling based on measurements, which is most likely due to lack of quantification of the ageing effect. In this study, a 3-year field experiment (2014-2016) with 10-minute paired wind speed measurements from one new and one malfunctioned (i.e., old bearings) SEAC SV5 cup anemometer which has been used by the Spanish Meteorological Agency in automatic weather stations since mid-1980s, was developed for assessing for the first time the role of anemometer drift on wind speed measurement. The results showed a statistical significant impact of anemometer drift on wind speed measurements, with the old anemometer measuring lower wind speeds than the new one. Biases show a marked temporal pattern and clear dependency on wind speed, with both weak and strong winds causing significant biases. This pioneering quantification of biases has allowed us to define two regression models that correct up to 37% of the artificial bias in wind speed due to measurement with an old anemometer.

  16. Welding pool measurement using thermal array sensor

    Science.gov (United States)

    Cho, Chia-Hung; Hsieh, Yi-Chen; Chen, Hsin-Yi

    2015-08-01

    Selective laser melting (SLM) is an additive manufacturing (AM) technology that uses a high-power laser beam to melt metal powder in chamber of inert gas. The process starts by slicing the 3D CAD data as a digital information source into layers to create a 2D image of each layer. Melting pool was formed by using laser irradiation on metal powders which then solidified to consolidated structure. In a selective laser melting process, the variation of melt pool affects the yield of a printed three-dimensional product. For three dimensional parts, the border conditions of the conductive heat transport have a very large influence on the melt pool dimensions. Therefore, melting pool is an important behavior that affects the final quality of the 3D object. To meet the temperature and geometry of the melting pool for monitoring in additive manufacturing technology. In this paper, we proposed the temperature sensing system which is composed of infrared photodiode, high speed camera, band-pass filter, dichroic beam splitter and focus lens. Since the infrared photodiode and high speed camera look at the process through the 2D galvanometer scanner and f-theta lens, the temperature sensing system can be used to observe the melting pool at any time, regardless of the movement of the laser spot. In order to obtain a wide temperature detecting range, 500 °C to 2500 °C, the radiation from the melting pool to be measured is filtered into a plurality of radiation portions, and since the intensity ratio distribution of the radiation portions is calculated by using black-body radiation. The experimental result shows that the system is suitable for melting pool to measure temperature.

  17. Developments in Emission Measurements Using Lightweight Sensors and Samplers.

    Science.gov (United States)

    Lightweight emission measurement systems making use of miniaturized sensors and samplers have been developed for portable and aerial sampling for an array of pollutants. Shoebox-sized systems called “Kolibri”, weighing 3-5 kg, have been deployed on NASA-flown unmanned...

  18. Image sensors for radiometric measurements in the ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Desa, E.S.; Desa, B.A.E.

    the sensors at a stabilised moderately cool temperature of 15 deg. C and to intelligently control the exposure time of the device, so as to reliably measure flux levels in the range 1 W/m super(2)/nm to 10/6 W/m super(2)/nm commonly encountered in the ocean...

  19. Multi-Functional Measurement Using a Single FBG Sensor

    NARCIS (Netherlands)

    Mizutani, Y.; Groves, R.M.

    2011-01-01

    This paper describes the measurement of average strain, strain distribution and vibration of a cantilever beam made of Carbon Fiber Reinforced Plastics (CFRP), using a single Fibre Bragg Grating (FBG) sensor mounted on the beam surface. Average strain is determined from the displacement of the peak

  20. Wind tunnel measurements of pollutant turbulent fluxes in urban intersections

    Science.gov (United States)

    Carpentieri, Matteo; Hayden, Paul; Robins, Alan G.

    2012-01-01

    Wind tunnel experiments have been carried out at the EnFlo laboratory to measure mean and turbulent tracer fluxes in geometries of real street canyon intersections. The work was part of the major DAPPLE project, focussing on the area surrounding the intersection between Marylebone Road and Gloucester Place in Central London, UK. Understanding flow and dispersion in urban streets is a very important issue for air quality management and planning, and turbulent mass exchange processes are important phenomena that are very often neglected in urban modelling studies. The adopted methodology involved the combined use of laser Doppler anemometry and tracer concentration measurements. This methodology was applied to quantify the mean and turbulent flow and dispersion fields within several street canyon intersections. Vertical profiles of turbulent tracer flux were also measured. The technique, despite a number of limitations, proved reliable and allowed tracer balance calculations to be undertaken in the selected street canyon intersections. The experience gained in this work will enable much more precise studies in the future as issues affecting the accuracy of the experimental technique have been identified and resolved.

  1. Precision Electron Density Measurements in the SSX MHD Wind Tunnel

    Science.gov (United States)

    Suen-Lewis, Emma M.; Barbano, Luke J.; Shrock, Jaron E.; Kaur, Manjit; Schaffner, David A.; Brown, Michael R.

    2017-10-01

    We characterize fluctuations of the line averaged electron density of Taylor states produced by the magnetized coaxial plasma gun of the SSX device using a 632.8 nm HeNe laser interferometer. The analysis method uses the electron density dependence of the refractive index of the plasma to determine the electron density of the Taylor states. Typical magnetic field and density values in the SSX device approach about B ≅ 0.3 T and n = 0 . 4 ×1016 cm-3 . Analysis is improved from previous density measurement methods by developing a post-processing method to remove relative phase error between interferometer outputs and to account for approximately linear phase drift due to low-frequency mechanical vibrations of the interferometer. Precision density measurements coupled with local measurements of the magnetic field will allow us to characterize the wave composition of SSX plasma via density vs. magnetic field correlation analysis, and compare the wave composition of SSX plasma with that of the solar wind. Preliminary results indicate that density and magnetic field appear negatively correlated. Work supported by DOE ARPA-E ALPHA program.

  2. Mixing height measurements from UHF wind profiling radar

    Energy Technology Data Exchange (ETDEWEB)

    Angevine, W.M.; Grimsdell, A.W. [CIRES, Univ. of Colorado, and NOAA Aeronomy Lab., Boulder, Colorado (United States)

    1997-10-01

    Mixing height in convective boundary layers can be detected by wind profiling radars (profilers) operating at or near 915 MHZ. We have made such measurements in a variety of settings including Alabama in 1992; Nova Scotia, Canada, during the North Atlantic Regional Experiment (NARE) 1993; Tennessee during the Southern Oxidant Study (SOS) 1994; near a 450 m tower in Wisconsin in 1995; and extensively in Illinois during the Flatland95, `96, and `97 experiments, as well as continuous operations at the Flatland Atmospheric Observatory. Profiler mixing height measurements, like all measurements, are subject to some limitations. The most important of these are due to rainfall, minimum height, and height resolution. Profilers are very sensitive to rain, which dominates the reflectivity and prevents the mixing height from being detected. Because the best height resolution is currently 60 m and the minimum height is 120-150 m AGL, the profiler is not suited for detecting mixing height in stable or nocturnal boundary layers. Problems may also arise in very dry or cold environments. (au) 12 refs.

  3. Study of Optical Fiber Sensors for Cryogenic Temperature Measurements.

    Science.gov (United States)

    De Miguel-Soto, Veronica; Leandro, Daniel; Lopez-Aldaba, Aitor; Beato-López, Juan Jesus; Pérez-Landazábal, José Ignacio; Auguste, Jean-Louis; Jamier, Raphael; Roy, Philippe; Lopez-Amo, Manuel

    2017-11-30

    In this work, the performance of five different fiber optic sensors at cryogenic temperatures has been analyzed. A photonic crystal fiber Fabry-Pérot interferometer, two Sagnac interferometers, a commercial fiber Bragg grating (FBG), and a π-phase shifted fiber Bragg grating interrogated in a random distributed feedback fiber laser have been studied. Their sensitivities and resolutions as sensors for cryogenic temperatures have been compared regarding their advantages and disadvantages. Additionally, the results have been compared with the given by a commercial optical backscatter reflectometer that allowed for distributed temperature measurements of a single mode fiber.

  4. FLEXIBLE PH SENSOR WITH POLYANILINE LAYER BASED ON IMPEDANCE MEASUREMENT

    OpenAIRE

    Chuang, Cheng-Hsin; Wu, Hsun-Pei; Chen, Cheng-Ho; Wu, Peng-Rong

    2012-01-01

    A flexible sensor with conducting polyaniline layer for detecting pH value based on the impedance measurement is fabricated and demonstrated in this study. The pH sensor consists of an interdigital electrode array on a flexible printed circuit and a thin-film polyaniline as the sensing layer. As the conductivity of polyaniline depends on the redox state, the impedance change of the polyaniline after it has reacted with different pH value solutions works as the sensing mechanism. In order to o...

  5. Study of Optical Fiber Sensors for Cryogenic Temperature Measurements

    Directory of Open Access Journals (Sweden)

    Veronica De Miguel-Soto

    2017-11-01

    Full Text Available In this work, the performance of five different fiber optic sensors at cryogenic temperatures has been analyzed. A photonic crystal fiber Fabry-Pérot interferometer, two Sagnac interferometers, a commercial fiber Bragg grating (FBG, and a π-phase shifted fiber Bragg grating interrogated in a random distributed feedback fiber laser have been studied. Their sensitivities and resolutions as sensors for cryogenic temperatures have been compared regarding their advantages and disadvantages. Additionally, the results have been compared with the given by a commercial optical backscatter reflectometer that allowed for distributed temperature measurements of a single mode fiber.

  6. Novel Sensor for the In Situ Measurement of Uranium Fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Hatfield, Kirk [Univ. of Florida, Gainesville, FL (United States)

    2015-02-10

    The goal of this project was to develop a sensor that incorporates the field-tested concepts of the passive flux meter to provide direct in situ measures of flux for uranium and groundwater in porous media. Measurable contaminant fluxes [J] are essentially the product of concentration [C] and groundwater flux or specific discharge [q ]. The sensor measures [J] and [q] by changes in contaminant and tracer amounts respectively on a sorbent. By using measurement rather than inference from static parameters, the sensor can directly advance conceptual and computational models for field scale simulations. The sensor was deployed in conjunction with DOE in obtaining field-scale quantification of subsurface processes affecting uranium transport (e.g., advection) and transformation (e.g., uranium attenuation) at the Rifle IFRC Site in Rifle, Colorado. Project results have expanded our current understanding of how field-scale spatial variations in fluxes of uranium, groundwater and salient electron donor/acceptors are coupled to spatial variations in measured microbial biomass/community composition, effective field-scale uranium mass balances, attenuation, and stability. The coupling between uranium, various nutrients and micro flora can be used to estimate field-scale rates of uranium attenuation and field-scale transitions in microbial communities. This research focuses on uranium (VI), but the sensor principles and design are applicable to field-scale fate and transport of other radionuclides. Laboratory studies focused on sorbent selection and calibration, along with sensor development and validation under controlled conditions. Field studies were conducted at the Rifle IFRC Site in Rifle, Colorado. These studies were closely coordinated with existing SBR (formerly ERSP) projects to complement data collection. Small field tests were conducted during the first two years that focused on evaluating field-scale deployment procedures and validating sensor performance under

  7. Development of Light Powered Sensor Networks for Thermal Comfort Measurement

    Directory of Open Access Journals (Sweden)

    Dasheng Lee

    2008-10-01

    Full Text Available Recent technological advances in wireless communications have enabled easy installation of sensor networks with air conditioning equipment control applications. However, the sensor node power supply, through either power lines or battery power, still presents obstacles to the distribution of the sensing systems. In this study, a novel sensor network, powered by the artificial light, was constructed to achieve wireless power transfer and wireless data communications for thermal comfort measurements. The sensing node integrates an IC-based temperature sensor, a radiation thermometer, a relative humidity sensor, a micro machined flow sensor and a microprocessor for predicting mean vote (PMV calculation. The 935 MHz band RF module was employed for the wireless data communication with a specific protocol based on a special energy beacon enabled mode capable of achieving zero power consumption during the inactive periods of the nodes. A 5W spotlight, with a dual axis tilt platform, can power the distributed nodes over a distance of up to 5 meters. A special algorithm, the maximum entropy method, was developed to estimate the sensing quantity of climate parameters if the communication module did not receive any response from the distributed nodes within a certain time limit. The light-powered sensor networks were able to gather indoor comfort-sensing index levels in good agreement with the comfort-sensing vote (CSV preferred by a human being and the experimental results within the environment suggested that the sensing system could be used in air conditioning systems to implement a comfort-optimal control strategy.

  8. LIDAR wind speed measurements from a rotating spinner (SpinnerEx 2009)

    DEFF Research Database (Denmark)

    Angelou, Nikolas; Mikkelsen, Torben; Hansen, Kasper Hjorth

    spinner of a MW-sized wind turbine, and investigate the approaching wind fields from this vantage point. Time series of wind speed measurements from the lidar with 50 Hz sampling rate were successfully obtained for approximately 60 days, during the measurement campaign lasting from April to August 2009....... In this report, information is given regarding the experimental setup and the lidar’s operation parameters. The geometrical model used for the reconstruction of the scanning pattern of the lidar is described. This model takes into account the lidar’s pointing direction, the spinner axis’s vertical tilt...... and the wind turbine’s yaw relative to the mean wind speed direction. The data analysis processes are documented. A methodology for the calculation of the yaw misalignment of the wind turbine relative to the wind direction, as a function of various averaging times, is proposed, using the lidar’s instantaneous...

  9. Windscanner: 3-D wind and turbulence measurements from three steerable doppler lidars

    International Nuclear Information System (INIS)

    Mikkelsen, T; Mann, J; Courtney, M; Sjoeholm, M

    2008-01-01

    At RISOe DTU we has started to build a new-designed laser-based lidar scanning facility for detailed remote measurements of the wind fields engulfing the huge wind turbines of today. Our aim is to measure in real-time 3D wind vector data at several hundred points every second: 1) upstream of the turbine, 2) near the turbine, and 3) in the wakes of the turbine rotors. Our first proto-type Windscanner is now being built from three commercially available Continuous Wave (CW) wind lidars modified with fast adjustable focus length and equipped with 2-D prism-based scan heads, in conjunction with a commercially available pulsed wind lidar for extended vertical profiling range. Design, construction and initial testing of the new 3-D wind lidar scanning facility are described and the functionality of the Windscanner and its potential as a new research facility within the wind energy community is discussed

  10. A real-time deflection monitoring system for wind turbine blades using a built-in laser displacement sensor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeong-Cheol; Giri, Paritosh; Lee, Jung-Ryul [Korea Chonbuk National Univ., Jeonbuk (Korea, Republic of). Dept. of Aerospace Engineering and LANL-CBNU Engineering Inst.

    2012-07-01

    Renewable energy is considered a good alternative to deal with the issues related to fossil fuel and environmental pollution. Wind energy as one of such renewable energy alternatives has seen a substantial growth. With commercially viable global wind power potential, wind energy penetration is further expected to rise, and so will the related problems. One of the issues is the collision of wind blade and tower during operation. To improve safety during operation, to minimize the risk of sudden failure or total breakdown, and to ensure reliable power generation and reduce wind turbine life cycle costs, a structural health monitoring (SHM) technology is required. This study proposes a single laser displacement sensor (LDS) system, where all of the rotating blades could be evaluated effectively. The system is cost-effective as well, as the system costs only a mere thousand dollars. If the blade bolt loosening occurs, it causes deflection in the affected blade. In a similar manner, nacelle tilt or mass loss damage in the blade will result in change of blade's position and the proposed system can identify such problems with ease. With increased demand of energy, the sizes of wind blades are getting bigger and bigger due to which people are installing wind turbines very high above the ground level or offshore. It is impractical to monitor the deflection through wired connection in these cases and hence can be replaced by a wireless solution. This wireless solution is achieved using Zigbee technology which operates in the industrial, scientific and medical (ISM) radio bands, typically 2.4 GHz, 915 MHz and 868 MHz. The output from the LDS is fed to the microcontroller which acts as an analog to digital converter which in turn is connected to the Zigbee transceiver module, which transmits the data. At the other end, the Zigbee reads the data and displays on the PC from where user can monitor the condition of wind blades. (orig.)

  11. Continued Development of Meandering Winding Magnetometer (MWM (Register Trademark)) Eddy Current Sensors for the Health Monitoring, Modeling and Damage Detection of Composite Overwrapped Pressure Vessels

    Science.gov (United States)

    Russell, Richard; Wincheski, Russell; Jablonski, David; Washabaugh, Andy; Sheiretov, Yanko; Martin, Christopher; Goldfine, Neil

    2011-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are used in essentially all NASA spacecraft, launch. vehicles and payloads to contain high-pressure fluids for propulsion, life support systems and science experiments. Failure of any COPV either in flight or during ground processing would result in catastrophic damage to the spacecraft or payload, and could lead to loss of life. Therefore, NASA continues to investigate new methods to non-destructively inspect (NDE) COPVs for structural anomalies and to provide a means for in-situ structural health monitoring (SHM) during operational service. Partnering with JENTEK Sensors, engineers at NASA, Kennedy Space Center have successfully conducted a proof-of-concept study to develop Meandering Winding Magnetometer (MWM) eddy current sensors designed to make direct measurements of the stresses of the internal layers of a carbon fiber composite wrapped COPV. During this study three different MWM sensors were tested at three orientations to demonstrate the ability of the technology to measure stresses at various fiber orientations and depths. These results showed good correlation with actual surface strain gage measurements. MWM-Array technology for scanning COPVs can reliably be used to image and detect mechanical damage. To validate this conclusion, several COPVs were scanned to obtain a baseline, and then each COPV was impacted at varying energy levels and then rescanned. The baseline subtracted images were used to demonstrate damage detection. These scans were performed with two different MWM-Arrays. with different geometries for near-surface and deeper penetration imaging at multiple frequencies and in multiple orientations of the linear MWM drive. This presentation will include a review of micromechanical models that relate measured sensor responses to composite material constituent properties, validated by the proof of concept study, as the basis for SHM and NDE data analysis as well as potential improvements including

  12. ''Nonisolated-sensor'' solid polystyrene absorbed dose measurements

    International Nuclear Information System (INIS)

    Zeitz, L.; Laughlin, J.S.

    1982-01-01

    A ''nonisolated-sensor'' solid polystyrene calorimeter was constructed to test the role of thermal diffusion in limiting the length of irradiation time during which temperature measurements with nonisolated sensors could be made sufficiently free of drift for determining dose with radiation fields such as gamma rays, x rays, and high-energy electrons. From measured ratios of dose at 5.0 and 0.5 cm in polystyrene and comparisons to dose measurements with a polystyrene parallel-plate (pancake) ion chamber, it was shown that thermal diffusion is sufficiently small in polystyrene to permit accurate measurements for irradiation periods of less than 20 min. Comparison of the absorbed dose measurements and depth dose ratios with pancake ion chambers and calorimeter showed, that within the precision and accuracy of the two measuring systems, there is close agreement. The nonisolated-sensor solid polystyrene calorimeter has the interesting features of (i) simplicity of construction, (ii) simplicity of operation without vacuum or feedback for temperature control, (iii) capability of simultaneous measurements at several depths and off-axis positions, (iv) the very small thermal defect correction with polystyrene, and (v) operation with the calorimeter in any orientation

  13. Nonisolated-sensor solid polystyrene absorbed dose measurements

    International Nuclear Information System (INIS)

    Zeitz, L.; Laughlin, J.S.

    1982-01-01

    A nonisolated-sensor solid polystyrene calorimeter was constructed to test the role of thermal diffusion in limiting the length of irradiation time during which temperature measurements with nonisolated sensors could be made sufficiently free of drift for determining dose with radiation fields such as gamma rays, x rays, and high-energy electrons. From measured ratios of dose at 5.0 and 0.5 cm in polystyrene and comparisons to dose measurements with a polystyrene parallel-plate (pancake) ion chamber, it was shown that thermal diffusion is sufficiently small in polystyrene to permit accurate measurements for irradiation periods of less than 20 min. Comparison of the absorbed dose measurements and depth dose ratios with pancake ion chambers and calorimeter showed, that within the precision and accuracy of the two measuring systems, there is close agreement. The nonisolated-sensor solid polystyrene calorimeter has the interesting features of (i) simplicity of construction, (ii) simplicity of operation without vacuum or feedback for temperature control, (iii) capability of simultaneous measurements at several depths and off-axis positions, (iv) the very small thermal defect correction with polystyrene, and (v) operation with the calorimeter in any orientation

  14. 3D wake measurements from a scanning wind lidar in combination with a fast wind field reconstruction model

    DEFF Research Database (Denmark)

    Mikkelsen, Torben Krogh; Herges, T. G.; Astrup, Poul

    2017-01-01

    University of Denmark. The purpose of the SpinnerLidar measurements at SWIFT is to measure the response of a V27 turbine wake to varying inflow conditions and turbine operating states. Although our fast scanning SpinnerLidar is able to measure the line-of-sight projected wind speed at up to 400 points per......-Stokes CFD code “Lincom Cyclop-buster model,”3 the corresponding 3D wind vector field (u, v, w) can be reconstructed under constraints for conservation of mass and momentum. The resulting model calculated line-of-sight projections of the 3D wind velocity vectors will become consistent with the line...

  15. Sensitivity analysis of nacelle lidar free stream wind speed measurements to wind-induction reconstruction model and lidar range configuration

    DEFF Research Database (Denmark)

    Svensson, Elin; Borraccino, Antoine; Meyer Forsting, Alexander Raul

    The sensitivity of nacelle lidar wind speed measurements to wind-induction models and lidar range configurations is studied using experimental data from the Nørrekær Enge (NKE) measurement campaign and simulated lidar data from Reynold-Averaged Navier Stokes (RANS) aerodynamic computational fluid...... the ZDM was configured to measure at five distances. From the configured distances, a large number of range configurations were created and systematically tested to determine the sensitivity of the reconstructed wind speeds to the number of ranges, minimum range and maximum range in the range......) of the fitting residuals. The results demonstrate that it is not possible to use RANS CFD simulated lidar data to determine optimal range configurations for real-time nacelle lidars due to their perfect (unrealistic) representation of the simulated flow field. The recommended range configurations are therefore...

  16. Multifuctional integrated sensors (MFISES).

    Energy Technology Data Exchange (ETDEWEB)

    Homeijer, Brian D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roozeboom, Clifton [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-01

    Many emerging IoT applications require sensing of multiple physical and environmental parameters for: completeness of information, measurement validation, unexpected demands, improved performance. For example, a typical outdoor weather station measures temperature, humidity, barometric pressure, light intensity, rainfall, wind speed and direction. Existing sensor technologies do not directly address the demand for cost, size, and power reduction in multi-paramater sensing applications. Industry sensor manufacturers have developed integrated sensor systems for inertial measurements that combine accelerometers, gyroscopes, and magnetometers, but do not address environmental sensing functionality. In existing research literature, a technology gap exists between the functionality of MEMS sensors and the real world applications of the sensors systems.

  17. Surface Acoustic Wave Vibration Sensors for Measuring Aircraft Flutter

    Science.gov (United States)

    Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

    2016-01-01

    Under NASA's Advanced Air Vehicles Program the Advanced Air Transport Technology (AATT) Project is investigating flutter effects on aeroelastic wings. To support that work a new method for measuring vibrations due to flutter has been developed. The method employs low power Surface Acoustic Wave (SAW) sensors. To demonstrate the ability of the SAW sensor to detect flutter vibrations the sensors were attached to a Carbon fiber-reinforced polymer (CFRP) composite panel which was vibrated at six frequencies from 1Hz to 50Hz. The SAW data was compared to accelerometer data and was found to resemble sine waves and match each other closely. The SAW module design and results from the tests are presented here.

  18. Measuring Conductance of Phenylenediamine as a Molecular Sensor

    Directory of Open Access Journals (Sweden)

    Taekyeong Kim

    2015-01-01

    Full Text Available We report experimental measurements of molecular conductance as a single molecular sensor by using scanning tunneling microscope-based break-junction (STM-BJ technique. The gap was created after Au atomic point contact was ruptured, and the target molecule was inserted and bonded to the top and bottom electrodes. We successfully measured the conductance for a series of amine-terminated oligophenyl molecules by forming the molecular junctions with Au electrodes. The measured conductance decays exponentially with molecular backbone length, enabling us to detect the type of molecules as a molecular sensor. Furthermore, we demonstrated reversible binary switching in a molecular junction by mechanical control of the gap between the electrodes. Since our method allows us to measure the conductance of a single molecule in ambient conditions, it should open up various practical molecular sensing applications.

  19. Measuring average angular velocity with a smartphone magnetic field sensor

    Science.gov (United States)

    Pili, Unofre; Violanda, Renante

    2018-02-01

    The angular velocity of a spinning object is, by standard, measured using a device called a tachometer. However, by directly using it in a classroom setting, the activity is likely to appear as less instructive and less engaging. Indeed, some alternative classroom-suitable methods for measuring angular velocity have been presented. In this paper, we present a further alternative that is smartphone-based, making use of the real-time magnetic field (simply called B-field in what follows) data gathering capability of the B-field sensor of the smartphone device as the timer for measuring average rotational period and average angular velocity. The in-built B-field sensor in smartphones has already found a number of uses in undergraduate experimental physics. For instance, in elementary electrodynamics, it has been used to explore the well-known Bio-Savart law and in a measurement of the permeability of air.

  20. Accounting for the speed shear in wind turbine power performance measurement

    DEFF Research Database (Denmark)

    Wagner, Rozenn

    the vertical wind shear and the turbulence intensity. The work presented in this thesis consists of the description and the investigation of a simple method to account for the wind speed shear in the power performance measurement. Ignoring this effect was shown to result in a power curve dependant on the shear...... for turbulence intensity suggested by Albers. The second method was found to be more suitable for normalising the power curve for the turbulence intensity. Using the equivalent wind speed accounting for the wind shear in the power performance measurement was shown to result in a more repeatable power curve than......The power curve of a wind turbine is the primary characteristic of the machine as it is the basis of the warranty for it power production. The current IEC standard for power performance measurement only requires the measurement of the wind speed at hub height and the air density to characterise...

  1. Modelling and measurements of wakes in large wind farms

    International Nuclear Information System (INIS)

    Barthelmie, R J; Rathmann, O; Frandsen, S T; Hansen, K S; Politis, E; Prospathopoulos, J; Rados, K; Cabezon, D; Schlez, W; Phillips, J; Neubert, A; Schepers, J G; Pijl, S P van der

    2007-01-01

    The paper presents research conducted in the Flow workpackage of the EU funded UPWIND project which focuses on improving models of flow within and downwind of large wind farms in complex terrain and offshore. The main activity is modelling the behaviour of wind turbine wakes in order to improve power output predictions

  2. Modelling and measurements of wakes in large wind farms

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Rathmann, Ole; Frandsen, Sten Tronæs

    2007-01-01

    The paper presents research conducted in the Flow workpackage of the EU funded UPWIND project which focuses on improving models of flow within and downwind of large wind farms in complex terrain and offshore. The main activity is modelling the behaviour of wind turbine wakes in order to improve...

  3. A fiber-optic current sensor for lightning measurement applications

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.

    2015-05-01

    An optical-fiber sensor based on Faraday Effect is developed for measuring total lightning electric current. It has many unique capabilities not possible with traditional current sensors. Designed for aircraft installation, the sensor is lightweight, non-conducting, structure-conforming, and is immune to electromagnetic interference, hysteresis and saturation. It can also be used on windmills, lightning towers, and can help validate lightning detection network measurements. Faraday Effect causes light polarization to rotate when the fiber is exposed to a magnetic field in the direction of light propagation. Thus, the magnetic field strength can be determined from the light polarization change. By forming closed fiber loops and applying Ampere's law, measuring the total light rotation yields the total current enclosed. The broadband, dual-detector, reflective polarimetric scheme allows measurement of both DC component and AC waveforms with about 60 dB dynamic range. Three sensor systems were built with different sensitivities from different laser wavelengths. Operating at 850nm, the first system uses twisted single-mode fiber and has a 150 A - 150 KA range. The second system operates at 1550nm, uses spun polarization maintaining fiber, and can measure 400 A - 400 KA. Both systems were validated with rocket-triggered lightning measurements and achieved excellent results when compared to a resistive shunt. The third system operates at 1310nm, uses spun polarization maintaining fiber, and can measure approximately 300 A - 300 KA. High current measurements up to 200 KA were demonstrated at a commercial lightning test facility. The system was recently installed on an aircraft and flown near icing weather conditions.

  4. A Fiber-Optic Current Sensor for Lightning Measurement Applications

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.

    2015-01-01

    An optical-fiber sensor based on Faraday Effect is developed for measuring total lightning electric current. It has many unique capabilities not possible with traditional current sensors. Designed for aircraft installation, the sensor is lightweight, non-conducting, structure-conforming, and is immune to electromagnetic interference, hysteresis and saturation. It can also be used on windmills, lightning towers, and can help validate lightning detection network measurements. Faraday Effect causes light polarization to rotate when the fiber is exposed to a magnetic field in the direction of light propagation. Thus, the magnetic field strength can be determined from the light polarization change. By forming closed fiber loops and applying Ampere's law, measuring the total light rotation yields the total current enclosed. The broadband, dual-detector, reflective polarimetric scheme allows measurement of both DC component and AC waveforms with about 60 dB dynamic range. Three sensor systems were built with different sensitivities from different laser wavelengths. Operating at 850nm, the first system uses twisted single-mode fiber and has a 150 A - 150 KA range. The second system operates at 1550nm, uses spun polarization maintaining fiber, and can measure 400 A - 400 KA. Both systems were validated with rocket-triggered lightning measurements and achieved excellent results when compared to a resistive shunt. The third system operates at 1310nm, uses spun polarization maintaining fiber, and can measure approximately 300 A - 300 KA. High current measurements up to 200 KA were demonstrated at a commercial lightning test facility. The system was recently installed on an aircraft and flown near icing weather conditions.

  5. Voyager microwave scintillation measurements of solar wind plasma parameters

    International Nuclear Information System (INIS)

    Martin, J.M.

    1985-01-01

    During the solar conjunctions of Voyager 1 and 2 spacecraft in August 1979, September 1980, and November 1982, temporal variations of intensity and frequency of the dual-wavelength (3.6 and 13 cm) radio transmissions from the spacecraft were observed and subsequently analyzed to infer characteristics of the solar wind plasma flow. Measurements of the temporal wave structure function were used to estimate the spectral index of the power law spatial spectrum of irregularities. Theoretical-intensity scintillation spectra were compared with measured intensity spectra to obtain least-squares estimates of (1) mean velocity, (2) random velocity, (3) axial ratio, and (4) electron density standard deviation. Uncertainties in parameter estimates were calculated by standard propagation of errors techniques. Mean velocity and electron density standard deviations in 1979-1980 show little dependence on solar latitude. Density standard deviation estimates were 3-10% of the background mean density and mean velocity estimates ranged from approx.200 km/s inside 17 solar radii to approx.300 km/s at 25 solar radii. 1982 density standard deviation estimates increased rapidly with latitude near 45 0 N, then sharply decreased north of that latitude, indicating the existence of a polar region of reduced fluctuations surrounded by a thin cone of strong density irregularities

  6. Laboratory measurements of grain-bedrock interactions using inertial sensors.

    Science.gov (United States)

    Maniatis, Georgios; Hoey, Trevor; Hodge, Rebecca; Valyrakis, Manousos; Drysdale, Tim

    2016-04-01

    Sediment transport in steep mountain streams is characterized by the movement of coarse particles (diameter c.100 mm) over beds that are not fully sediment-covered. Under such conditions, individual grain dynamics become important for the prediction of sediment movement and subsequently for understanding grain-bedrock interaction. Technological advances in micro-mechanical-electrical systems now provide opportunities to measure individual grain dynamics and impact forces from inside the sediments (grain inertial frame of reference) instead of trying to infer them indirectly from water flow dynamics. We previously presented a new prototype sensor specifically developed for monitoring sediment transport [Maniatis et al. EGU 2014], and have shown how the definition of the physics of the grain using the inertial frame and subsequent derived measurements which have the potential to enhance the prediction of sediment entrainment [Maniatis et al. 2015]. Here we present the latest version of this sensor and we focus on beginning of the cessation of grain motion: the initial interaction with the bed after the translation phase. The sensor is housed in a spherical case, diameter 80mm, and is constructed using solid aluminum (density = 2.7 kg.m-3) after detailed 3D-CAD modelling. A complete Inertial Measurement Unit (a combination of micro- accelerometer, gyroscope and compass) was placed at the center of the mass of the assembly, with measurement ranges of 400g for acceleration, and 1200 rads/sec for angular velocity. In a 0.9m wide laboratory flume, bed slope = 0.02, the entrainment threshold of the sensor was measured, and the water flow was then set to this value. The sensor was then rolled freely from a static cylindrical bar positioned exactly on the surface of the flowing water. As the sensor enters the flow we record a very short period of transport (1-1.5 sec) followed by the impact on the channel bed. The measured Total Kinetic Energy (Joules) includes the

  7. A Fiber-Optic Aircraft Lightning Current Measurement Sensor

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.

    2013-01-01

    A fiber-optic current sensor based on the Faraday Effect is developed for aircraft installations. It can measure total lightning current amplitudes and waveforms, including continuing current. Additional benefits include being small, lightweight, non-conducting, safe from electromagnetic interference, and free of hysteresis and saturation. The Faraday Effect causes light polarization to rotate in presence of magnetic field in the direction of light propagation. Measuring the total induced light polarization change yields the total current enclosed. The system operates at 1310nm laser wavelength and can measure approximately 300 A - 300 kA, a 60 dB range. A reflective polarimetric scheme is used, where the light polarization change is measured after a round-trip propagation through the fiber. A two-detector setup measures the two orthogonal polarizations for noise subtraction and improved dynamic range. The current response curve is non-linear and requires a simple spline-fit correction. Effects of high current were achieved in laboratory using combinations of multiple fiber and wire loops. Good result comparisons against reference sensors were achieved up to 300 kA. Accurate measurements on a simulated aircraft fuselage and an internal structure illustrate capabilities that maybe difficult with traditional sensors. Also tested at a commercial lightning test facility from 20 kA to 200 kA, accuracy within 3-10% was achieved even with non-optimum setups.

  8. Method for Estimating Evaporative Potential (IM/CLO) from ASTM Standard Single Wind Velocity Measures

    Science.gov (United States)

    2016-08-10

    IM/CLO) FROM ASTM STANDARD SINGLE WIND VELOCITY MEASURES DISCLAIMER The opinions or assertions contained herein are the private views of the...USARIEM TECHNICAL REPORT T16-14 METHOD FOR ESTIMATING EVAPORATIVE POTENTIAL (IM/CLO) FROM ASTM STANDARD SINGLE WIND VELOCITY... ASTM STANDARD SINGLE WIND VELOCITY MEASURES Adam W. Potter Biophysics and Biomedical Modeling Division U.S. Army Research Institute of Environmental

  9. Wireless Sensor Node for Surface Seawater Density Measurements

    Directory of Open Access Journals (Sweden)

    Roberto Saletti

    2012-03-01

    Full Text Available An electronic meter to measure surface seawater density is presented. It is based on the measurement of the difference in displacements of a surface level probe and a weighted float, which according to Archimedes’ law depends on the density of the water. The displacements are simultaneously measured using a high-accuracy magnetostrictive sensor, to which a custom electronic board provides a wireless connection and power supply so that it can become part of a wireless sensor network. The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller. Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network. The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings.

  10. Wireless sensor node for surface seawater density measurements.

    Science.gov (United States)

    Baronti, Federico; Fantechi, Gabriele; Roncella, Roberto; Saletti, Roberto

    2012-01-01

    An electronic meter to measure surface seawater density is presented. It is based on the measurement of the difference in displacements of a surface level probe and a weighted float, which according to Archimedes' law depends on the density of the water. The displacements are simultaneously measured using a high-accuracy magnetostrictive sensor, to which a custom electronic board provides a wireless connection and power supply so that it can become part of a wireless sensor network. The electronics are designed so that different kinds of wireless networks can be used, by simply changing the wireless module and the relevant firmware of the microcontroller. Lastly, laboratory and at-sea tests are presented and discussed in order to highlight the functionality and the performance of a prototype of the wireless density meter node in a Bluetooth radio network. The experimental results show a good agreement of the values of the calculated density compared to reference hydrometer readings.

  11. Measurement system for nitrous oxide based on amperometric gas sensor

    Science.gov (United States)

    Siswoyo, S.; Persaud, K. C.; Phillips, V. R.; Sneath, R.

    2017-03-01

    It has been well known that nitrous oxide is an important greenhouse gas, so monitoring and control of its concentration and emission is very important. In this work a nitrous oxide measurement system has been developed consisting of an amperometric sensor and an appropriate lab-made potentiostat that capable measuring picoampere current ranges. The sensor was constructed using a gold microelectrode as working electrode surrounded by a silver wire as quasi reference electrode, with tetraethyl ammonium perchlorate and dimethylsulphoxide as supporting electrolyte and solvent respectively. The lab-made potentiostat was built incorporating a transimpedance amplifier capable of picoampere measurements. This also incorporated a microcontroller based data acquisition system, controlled by a host personal computer using a dedicated computer program. The system was capable of detecting N2O concentrations down to 0.07 % v/v.

  12. Internal Interface Diversification as a Security Measure in Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sampsa Rauti

    2018-03-01

    Full Text Available More actuator and sensor devices are connected to the Internet of Things (IoT every day, and the network keeps growing, while software security of the devices is often incomplete. Sensor networks and the IoT in general currently cover a large number of devices with an identical internal interface structure. By diversifying the internal interfaces, the interfaces on each node of the network are made unique, and it is possible to break the software monoculture of easily exploitable identical systems. This paper proposes internal interface diversification as a security measure for sensor networks. We conduct a study on diversifiable internal interfaces in 20 IoT operating systems. We also present two proof-of-concept implementations and perform experiments to gauge the feasibility in the IoT environment. Internal interface diversification has practical limitations, and not all IoT operating systems have that many diversifiable interfaces. However, because of low resource requirements, compatibility with other security measures and wide applicability to several interfaces, we believe internal interface diversification is a promising and effective approach for securing nodes in sensor networks.

  13. Power and loads for wind turbines in yawed conditions. Analysis of field measurements and aerodynamic predictions

    Energy Technology Data Exchange (ETDEWEB)

    Boorsma, K. [ECN Wind Energy, Petten (Netherlands)

    2012-11-15

    A description is given of the work carried out within the framework of the FLOW (Far and Large Offshore Wind) project on single turbine performance in yawed flow conditions. Hereto both field measurements as well as calculations with an aerodynamic code are analyzed. The rotors of horizontal axis wind turbines follow the changes in the wind direction for optimal performance. The reason is that the power is expected to decrease for badly oriented rotors. So, insight in the effects of the yaw angle on performance is important for optimization of the yaw control of each individual turbine. The effect of misalignment on performance and loads of a single 2.5 MW wind turbine during normal operation is investigated. Hereto measurements at the ECN Wind Turbine Test Site Wieringermeer (EWTW) are analyzed from December 2004 until April 2009. Also, the influence of yaw is studied using a design code and results from this design code are compared with wind tunnel measurements.

  14. Summary Report: The Shadow effect of large wind farms: measurements, data analysis and modelling

    DEFF Research Database (Denmark)

    Frandsen, Sten Tronæs; Barthelmie, Rebecca Jane; Rathmann, Ole

    It was the goal of the project – by means of data from the demonstration wind farms Horns Rev and Nysted, analyses of these data and modelling – to facilitate prediction of the power losses from a wind farm should a new wind farm be built upwind relative to the prevailing wind direction...... it may appropriate to build new wind farms rather close to the existing wind farms. A relevant question is therefore how far away new wind farms must be placed to avoid too large power losses. Measurements have been carried out for several years at the two sites, and databases have been prepared....... Thus, if different modelling efforts results in comparable results, the quality of the models will be tested outside the physical range where data are available. All considered the project participants find that the project has been immensely successful. The main achievements of the project are...

  15. A comprehensive measure of the energy resource: Wind power potential (WPP)

    International Nuclear Information System (INIS)

    Zhang, Jie; Chowdhury, Souma; Messac, Achille

    2014-01-01

    data at four differing stations in the state of North Dakota. The results illustrate the variation of wind conditions and, subsequently, its influence on the quality of wind resources. A comparison of four sites in North Dakota shows that WPD and WPP follow different trends, and the ranking of candidate sites in terms of a realistic resource potential measure is not captured by WPD

  16. The « 3-D donut » electrostatic analyzer for millisecond timescale electron measurements in the solar wind

    Science.gov (United States)

    Berthomier, M.; Techer, J. D.

    2017-12-01

    Understanding electron acceleration mechanisms in planetary magnetospheres or energy dissipation at electron scale in the solar wind requires fast measurement of electron distribution functions on a millisecond time scale. Still, since the beginning of space age, the instantaneous field of view of plasma spectrometers is limited to a few degrees around their viewing plane. In Earth's magnetosphere, the NASA MMS spacecraft use 8 state-of-the-art sensor heads to reach a time resolution of 30 milliseconds. This costly strategy in terms of mass and power consumption can hardly be extended to the next generation of constellation missions that would use a large number of small-satellites. In the solar wind, using the same sensor heads, the ESA THOR mission is expected to reach the 5ms timescale in the thermal energy range, up to 100eV. We present the « 3-D donut » electrostatic analyzer concept that can change the game for future space missions because of its instantaneous hemispheric field of view. A set of 2 sensors is sufficient to cover all directions over a wide range of energy, e.g. up to 1-2keV in the solar wind, which covers both thermal and supra-thermal particles. In addition, its high sensitivity compared to state of the art instruments opens the possibility of millisecond time scale measurements in space plasmas. With CNES support, we developed a high fidelity prototype (a quarter of the full « 3-D donut » analyzer) that includes all electronic sub-systems. The prototype weights less than a kilogram. The key building block of the instrument is an imaging detector that uses EASIC, a low-power front-end electronics that will fly on the ESA Solar Orbiter and on the NASA Parker Solar Probe missions.

  17. Measurements of Operational Wind Turbine Noise in UK Waters.

    Science.gov (United States)

    Cheesman, Samuel

    2016-01-01

    The effects of wind farm operational noise have not been addressed to the same extent as their construction methods such as piling and drilling of the foundations despite their long operational lifetimes compared with weeks of construction. The results of five postconstruction underwater sound-monitoring surveys on wind farms located throughout the waters of the British Isles are discussed. These wind farms consist of differing turbine power outputs, from 3 to 3.6 MW, and differing numbers of turbines. This work presents an overview of the results obtained and discusses both the levels and frequency components of the sound in several metrics.

  18. Detection and Classification of Transformer Winding Mechanical Faults Using UWB Sensors and Bayesian Classifier

    Science.gov (United States)

    Alehosseini, Ali; A. Hejazi, Maryam; Mokhtari, Ghassem; B. Gharehpetian, Gevork; Mohammadi, Mohammad

    2015-06-01

    In this paper, the Bayesian classifier is used to detect and classify the radial deformation and axial displacement of transformer windings. The proposed method is tested on a model of transformer for different volumes of radial deformation and axial displacement. In this method, ultra-wideband (UWB) signal is sent to the simplified model of the transformer winding. The received signal from the winding model is recorded and used for training and testing of Bayesian classifier in different axial displacement and radial deformation states of the winding. It is shown that the proposed method has a good accuracy to detect and classify the axial displacement and radial deformation of the winding.

  19. Implementation of a new maximum power point tracking control strategy for small wind energy conversion systems without mechanical sensors

    International Nuclear Information System (INIS)

    Daili, Yacine; Gaubert, Jean-Paul; Rahmani, Lazhar

    2015-01-01

    Highlights: • A new maximum power point tracking algorithm for small wind turbines is proposed. • This algorithm resolves the problems of the classical perturb and observe method. • The proposed method has been tested under several wind speed profiles. • The validity of the new algorithm has been confirmed by the experimental results. - Abstract: This paper proposes a modified perturbation and observation maximum power point tracking algorithm for small wind energy conversion systems to overcome the problems of the conventional perturbation and observation technique, namely rapidity/efficiency trade-off and the divergence from peak power under a fast variation of the wind speed. Two modes of operation are used by this algorithm, the normal perturbation and observation mode and the predictive mode. The normal perturbation and observation mode with small step-size is switched under a slow wind speed variation to track the true maximum power point with fewer fluctuations in steady state. When a rapid change of wind speed is detected, the algorithm tracks the new maximum power point in two phases: in the first stage, the algorithm switches to the predictive mode in which the step-size is auto-adjusted according to the distance between the operating point and the estimated optimum point to move the operating point near to the maximum power point rapidly, and then the normal perturbation and observation mode is used to track the true peak power in the second stage. The dc-link voltage variation is used to detect rapid wind changes. The proposed algorithm does not require either knowledge of system parameters or of mechanical sensors. The experimental results confirm that the proposed algorithm has a better performance in terms of dynamic response and efficiency compared with the conventional perturbation and observation algorithm

  20. Wind field reconstruction from nacelle-mounted lidar short-range measurements

    Directory of Open Access Journals (Sweden)

    A. Borraccino

    2017-05-01

    Full Text Available Profiling nacelle lidars probe the wind at several heights and several distances upstream of the rotor. The development of such lidar systems is relatively recent, and it is still unclear how to condense the lidar raw measurements into useful wind field characteristics such as speed, direction, vertical and longitudinal gradients (wind shear. In this paper, we demonstrate an innovative method to estimate wind field characteristics using nacelle lidar measurements taken within the induction zone. Model-fitting wind field reconstruction techniques are applied to nacelle lidar measurements taken at multiple distances close to the rotor, where a wind model is combined with a simple induction model. The method allows robust determination of free-stream wind characteristics. The method was applied to experimental data obtained with two different types of nacelle lidar (five-beam Demonstrator and ZephIR Dual Mode. The reconstructed wind speed was within 0.5 % of the wind speed measured with a mast-top-mounted cup anemometer at 2.5 rotor diameters upstream of the turbine. The technique described in this paper overcomes measurement range limitations of the currently available nacelle lidar technology.

  1. Multi-MW wind turbine power curve measurements using remote sensing instruments - the first Hoevsoere campaign

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, R.; Courtney, M.

    2009-02-15

    Power curve measurement for large wind turbines requires taking into account more parameters than only the wind speed at hub height. Based on results from aerodynamic simulations, an equivalent wind speed taking the wind shear into account was defined and found to reduce the scatter in the power curve significantly. Two LiDARs and a SoDAR are used to measure the wind profile in front of a wind turbine. These profiles are used to calculate the equivalent wind speed. LiDAR are found to be more accurate than SoDAR and therefore more suitable for power performance measurement. The equivalent wind speed calculated from LiDAR profile measurements gave a small reduction of the power curve uncertainty. Several factors can explain why this difference is smaller than expected, including the experimental design and errors pertaining to the LiDAR at that time. This first measurement campaign shows that used of the equivalent wind speed at least results in a power curve with no more scatter than using the conventional method. (au)

  2. Evaluation of the Wind Flow Variability Using Scanning Doppler Lidar Measurements

    Science.gov (United States)

    Sand, S. C.; Pichugina, Y. L.; Brewer, A.

    2016-12-01

    Better understanding of the wind flow variability at the heights of the modern turbines is essential to accurately assess of generated wind power and efficient turbine operations. Nowadays the wind energy industry often utilizes scanning Doppler lidar to measure wind-speed profiles at high spatial and temporal resolution.The study presents wind flow features captured by scanning Doppler lidars during the second Wind Forecast and Improvement Project (WFIP 2) sponsored by the Department of Energy (DOE) and National Oceanic and Atmospheric Administration (NOAA). This 18-month long experiment in the Columbia River Basin aims to improve model wind forecasts complicated by mountain terrain, coastal effects, and numerous wind farms.To provide a comprehensive dataset to use for characterizing and predicting meteorological phenomena important to Wind Energy, NOAA deployed scanning, pulsed Doppler lidars to two sites in Oregon, one at Wasco, located upstream of all wind farms relative to the predominant westerly flow in the region, and one at Arlington, located in the middle of several wind farms.In this presentation we will describe lidar scanning patterns capable of providing data in conical, or vertical-slice modes. These individual scans were processed to obtain 15-min averaged profiles of wind speed and direction in real time. Visualization of these profiles as time-height cross sections allows us to analyze variability of these parameters with height, time and location, and reveal periods of rapid changes (ramp events). Examples of wind flow variability between two sites of lidar measurements along with examples of reduced wind velocity downwind of operating turbines (wakes) will be presented.

  3. How well can we measure the vertical wind speed? Implications for fluxes of energy and mass

    Science.gov (United States)

    John Kochendorfer; Tilden P. Meyers; John Frank; William J. Massman; Mark W. Heuer

    2012-01-01

    Sonic anemometers are capable of measuring the wind speed in all three dimensions at high frequencies (10­50 Hz), and are relied upon to estimate eddy-covariance-based fluxes of mass and energy over a wide variety of surfaces and ecosystems. In this study, wind-velocity measurement errors from a three-dimensional sonic anemometer with a nonorthogonal transducer...

  4. Measurement uncertainty budget of an interferometric flow velocity sensor

    Science.gov (United States)

    Bermuske, Mike; Büttner, Lars; Czarske, Jürgen

    2017-06-01

    Flow rate measurements are a common topic for process monitoring in chemical engineering and food industry. To achieve the requested low uncertainties of 0:1% for flow rate measurements, a precise measurement of the shear layers of such flows is necessary. The Laser Doppler Velocimeter (LDV) is an established method for measuring local flow velocities. For exact estimation of the flow rate, the flow profile in the shear layer is of importance. For standard LDV the axial resolution and therefore the number of measurement points in the shear layer is defined by the length of the measurement volume. A decrease of this length is accompanied by a larger fringe distance variation along the measurement axis which results in a rise of the measurement uncertainty for the flow velocity (uncertainty relation between spatial resolution and velocity uncertainty). As a unique advantage, the laser Doppler profile sensor (LDV-PS) overcomes this problem by using two fan-like fringe systems to obtain the position of the measured particles along the measurement axis and therefore achieve a high spatial resolution while it still offers a low velocity uncertainty. With this technique, the flow rate can be estimated with one order of magnitude lower uncertainty, down to 0:05% statistical uncertainty.1 And flow profiles especially in film flows can be measured more accurately. The problem for this technique is, in contrast to laboratory setups where the system is quite stable, that for industrial applications the sensor needs a reliable and robust traceability to the SI units, meter and second. Small deviations in the calibration can, because of the highly position depending calibration function, cause large systematic errors in the measurement result. Therefore, a simple, stable and accurate tool is needed, that can easily be used in industrial surroundings to check or recalibrate the sensor. In this work, different calibration methods are presented and their influences to the

  5. Control con dos sensores para energías eólica y solar; Control with two sensors for energies wind and solar

    Directory of Open Access Journals (Sweden)

    Alfredo G M Gámez López

    2011-02-01

    Full Text Available En el artículo se realiza un análisis de dos sensores que se aplican en energías renovables (eólica y solar,obteniéndose una ley de control óptima. Para las fuentes energéticas elegidas se proponen técnicas de altafrecuencia de conmutación y eficiencia. Para la validación de los resultados se emplean técnicas desimulación digital In this article we make an analysis of two sensors applied in renewable energies (wind and solar,obtaining an ideal law of control. For the chosen energetic sources there appear technologies of highfrequency of commutation and of high efficiency. Technologies of digital simulation validate the results.

  6. Fiber-Optic Current Sensor Validation with Triggered Lightning Measurements

    Science.gov (United States)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

    2013-01-01

    A fiber optic current sensor based on the Faraday Effect is developed that is highly suitable for aircraft installation and can measure total current enclosed in a fiber loop down to DC. Other attributes include being small, light-weight, non-conducting, safe from electromagnetic interference, and free of hysteresis and saturation. The Faraday Effect causes light polarization to rotate when exposed to a magnetic field in the direction of light propagation. Measuring the induced light polarization rotation in fiber loops yields the total current enclosed. Two sensor systems were constructed and installed at Camp Blanding, Florida, measuring rocket-triggered lightning. The systems were similar in design but with different laser wavelengths, sensitivities and ranges. Results are compared to a shunt resistor as reference. The 850nm wavelength system tested in summer 2011 showed good result comparison early. However, later results showed gradual amplitude increase with time, attributed to corroded connections affecting the 50-ohm output termination. The 1550nm system also yielded good results in the summer 2012. The successful measurements demonstrate the fiber optic sensor's accuracies in capturing real lightning currents, and represent an important step toward future aircraft installation.

  7. Noninvasive blood pressure measurement scheme based on optical fiber sensor

    Science.gov (United States)

    Liu, Xianxuan; Yuan, Xueguang; Zhang, Yangan

    2016-10-01

    Optical fiber sensing has many advantages, such as volume small, light quality, low loss, strong in anti-jamming. Since the invention of the optical fiber sensing technology in 1977, optical fiber sensing technology has been applied in the military, national defense, aerospace, industrial, medical and other fields in recent years, and made a great contribution to parameter measurement in the environment under the limited condition .With the rapid development of computer, network system, the intelligent optical fiber sensing technology, the sensor technology, the combination of computer and communication technology , the detection, diagnosis and analysis can be automatically and efficiently completed. In this work, we proposed a noninvasive blood pressure detection and analysis scheme which uses optical fiber sensor. Optical fiber sensing system mainly includes the light source, optical fiber, optical detector, optical modulator, the signal processing module and so on. wavelength optical signals were led into the optical fiber sensor and the signals reflected by the human body surface were detected. By comparing actual testing data with the data got by traditional way to measure the blood pressure we can establish models for predicting the blood pressure and achieve noninvasive blood pressure measurement by using spectrum analysis technology. Blood pressure measurement method based on optical fiber sensing system is faster and more convenient than traditional way, and it can get accurate analysis results in a shorter period of time than before, so it can efficiently reduce the time cost and manpower cost.

  8. Measurements of UWB Pulse Propagation Along a Wind Turbine Blade at 1 to 20 GHz

    DEFF Research Database (Denmark)

    Hejselbæk, Johannes; Syrytsin, Igor A.; Eggers, Patrick Claus F.

    2018-01-01

    This paper describes propagation measurements of an Ultra Wide Band (UWB) pulse along a full-scale wind turbine blade. The aim is to use the UWB channel characteristics to determine the deflection of the wind turbine blade under different wind loads. The frequency response is measured from 1 to 20...... the reflection originates a ray-tracing study incorporating a model of the curvature of the blade have been conducted. This showed the area causing the reflections depended highly on the placement of the antenna on the wind turbine blade....

  9. LIDAR wind speed measurements from a rotating spinner (SpinnerEx 2009)

    Energy Technology Data Exchange (ETDEWEB)

    Angelou, N.; Mikkelsen, Torben; Hansen, Kasper H.; Sjoeholm, M.; Harris, M.

    2010-08-15

    In the context of the increasing application of remote sensing techniques in wind energy, the feasibility of upwind observations via a spinner-mounted wind lidar was tested during the SpinnerEx 2009 experiment. The objective was to install a QinetiQ (Natural Power) ZephIR lidar in the rotating spinner of a MW-sized wind turbine, and investigate the approaching wind fields from this vantage point. Time series of wind speed measurements from the lidar with 50 Hz sampling rate were successfully obtained for approximately 60 days, during the measurement campaign lasting from April to August 2009. In this report, information is given regarding the experimental setup and the lidar's operation parameters. The geometrical model used for the reconstruction of the scanning pattern of the lidar is described. This model takes into account the lidar's pointing direction, the spinner axis's vertical tilt and the wind turbine's yaw relative to the mean wind speed direction. The data analysis processes are documented. A methodology for the calculation of the yaw misalignment of the wind turbine relative to the wind direction, as a function of various averaging times, is proposed, using the lidar's instantaneous line-of-sight radial wind speed measurements. Two different setups have been investigated in which the approaching wind field was measured at distances of 0.58 OE and 1.24 OE rotor diameters upwind, respectively. For both setups, the instantaneous yaw misalignment of the turbine has been estimated from the lidar measurements. Data from an adjacent meteorological mast as well as data logged within the wind turbine's control system were used to evaluate the results. (author)

  10. Development of an optical fiber sensor for angular displacement measurements.

    Science.gov (United States)

    Jung, Gu-In; Kim, Ji-Sun; Lee, Tae-Hee; Choi, Ju-Hyeon; Oh, Han-Byeol; Kim, A-Hee; Eom, Gwang-Moon; Lee, Jeong-Hwan; Chung, Soon-Cheol; Park, Jong-Rak; Lee, Young-Jae; Park, Hee-Jung; Jun, Jae-Hoon

    2014-01-01

    For diagnostic and therapeutic purposes, the joint angle measurement of a patient after an accident or a surgical operation is significant for monitoring and evaluating the recovering process. This paper proposed an optical fiber sensor for the measurement of angular displacement. The effect of beveled fiber angle on the detected light signal was investigated to find an appropriate mathematical model. Beveled fiber tips redirected the light over a range of angles away from the fiber axis. Inverse polynomial models were applied to directly obtain and display the joint angle change in real time with the Lab-VIEW program. The actual joint angle correlated well with the calculated LabVIEW output angle over the test range. The proposed optical sensor is simple, cost effective, small in size, and can evaluate the joint angle in real time. This method is expected to be useful in the field of rehabilitation and sport science.

  11. Preliminary development of a fiber optic sensor for measuring bilirubin.

    Science.gov (United States)

    Babin, Steven M; Sova, Raymond M

    2014-01-01

    Preliminary development of a fiber optic bilirubin sensor is described, where an unclad sensing portion is used to provide evanescent wave interaction of the transmitted light with the chemical environment. By using a wavelength corresponding to a bilirubin absorption peak, the Beer-Lambert Law can be used to relate the concentration of bilirubin surrounding the sensing portion to the amount of absorbed light. Initial testing in vitro suggests that the sensor response is consistent with the results of bulk absorption measurements as well as the Beer-Lambert Law. In addition, it is found that conjugated and unconjugated bilirubin have different peak absorption wavelengths, so that two optical frequencies may potentially be used to measure both types of bilirubin. Future development of this device could provide a means of real-time, point-of-care monitoring of intravenous bilirubin in critical care neonates with hyperbilirubinemia.

  12. Preliminary Development of a Fiber Optic Sensor for Measuring Bilirubin

    Directory of Open Access Journals (Sweden)

    Steven M. Babin

    2014-01-01

    Full Text Available Preliminary development of a fiber optic bilirubin sensor is described, where an unclad sensing portion is used to provide evanescent wave interaction of the transmitted light with the chemical environment. By using a wavelength corresponding to a bilirubin absorption peak, the Beer–Lambert Law can be used to relate the concentration of bilirubin surrounding the sensing portion to the amount of absorbed light. Initial testing in vitro suggests that the sensor response is consistent with the results of bulk absorption measurements as well as the Beer–Lambert Law. In addition, it is found that conjugated and unconjugated bilirubin have different peak absorption wavelengths, so that two optical frequencies may potentially be used to measure both types of bilirubin. Future development of this device could provide a means of real-time, point-of-care monitoring of intravenous bilirubin in critical care neonates with hyperbilirubinemia.

  13. Pilot-scale concept of real-time wind speed-matching wind tunnel for measurements of gaseous emissions

    Science.gov (United States)

    Comprehensive control of odors, hydrogen sulfide (H2S), ammonia (NH3) and odorous volatile organic compound (VOC) emissions associated with animal production is a critical need. Current methods utilizing wind tunnels and flux chambers for measurements of gaseous emissions from area sources such as f...

  14. Link-quality measurement and reporting in wireless sensor networks.

    Science.gov (United States)

    Chehri, Abdellah; Jeon, Gwanggil; Choi, Byoungjo

    2013-03-04

    Wireless Sensor networks (WSNs) are created by small hardware devices that possess the necessary functionalities to measure and exchange a variety of environmental data in their deployment setting. In this paper, we discuss the experiments in deploying a testbed as a first step towards creating a fully functional heterogeneous wireless network-based underground monitoring system. The system is mainly composed of mobile and static ZigBee nodes, which are deployed on the underground mine galleries for measuring ambient temperature. In addition, we describe the measured results of link characteristics such as received signal strength, latency and throughput for different scenarios.

  15. Link-Quality Measurement and Reporting in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Byoungjo Choi

    2013-03-01

    Full Text Available Wireless Sensor networks (WSNs are created by small hardware devices that possess the necessary functionalities to measure and exchange a variety of environmental data in their deployment setting. In this paper, we discuss the experiments in deploying a testbed as a first step towards creating a fully functional heterogeneous wireless network-based underground monitoring system. The system is mainly composed of mobile and static ZigBee nodes, which are deployed on the underground mine galleries for measuring ambient temperature. In addition, we describe the measured results of link characteristics such as received signal strength, latency and throughput for different scenarios.

  16. The measurement of winds over the ocean from Skylab with application to measuring and forecasting typhoons and hurricanes

    Science.gov (United States)

    Cardone, V. J.; Pierson, W. J.

    1975-01-01

    On Skylab, a combination microwave radar-radiometer (S193) made measurements in a tropical hurricane (AVA), a tropical storm, and various extratropical wind systems. The winds at each cell scanned by the instrument were determined by objective numerical analysis techniques. The measured radar backscatter is compared to the analyzed winds and shown to provide an accurate method for measuring winds from space. An operational version of the instrument on an orbiting satellite will be able to provide the kind of measurements in tropical cyclones available today only by expensive and dangerous aircraft reconnaissance. Additionally, the specifications of the wind field in the tropical boundary layer should contribute to improved accuracy of tropical cyclone forecasts made with numerical weather predictions models currently being applied to the tropical atmosphere.

  17. Sensor

    OpenAIRE

    Gleeson, Helen; Dierking, Ingo; Grieve, Bruce; Woodyatt, Christopher; Brimicombe, Paul

    2015-01-01

    An electrical temperature sensor (10) comprises a liquid crystalline material (12). First and second electrically conductive contacts (14), (16), having a spaced relationship there between, contact the liquid crystalline material (12). An electric property measuring device is electrically connected to the first and second contacts (14), (16) and is arranged to measure an electric property of the liquid crystalline material (12). The liquid crystalline material (12) has a transition temperatur...

  18. Ground-Based Remote or In Situ Measurement of Vertical Profiles of Wind in the Lower Troposphere

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, Andrew; Newman, Jennifer

    2017-02-24

    Knowledge of winds in the lower troposphere is essential for a range of applications, including weather forecasting, transportation, natural hazards, and wind energy. This presentation focuses on the measurement of vertical profiles of wind in the lower troposphere for wind energy applications. This presentation introduces the information that wind energy site development and operations require, how it used, and the benefits and problems of current measurements from in-situ measurements and remote sensing. The development of commercial Doppler wind lidar systems over the last 10 years are shown, along with the lessons learned from this experience. Finally, potential developments in wind profiling aimed at reducing uncertainty and increasing data availability are introduced.

  19. Coherent Uncertainty Analysis of Aerosol Measurements from Multiple Satellite Sensors

    Science.gov (United States)

    Petrenko, M.; Ichoku, C.

    2013-01-01

    Aerosol retrievals from multiple spaceborne sensors, including MODIS (on Terra and Aqua), MISR, OMI, POLDER, CALIOP, and SeaWiFS altogether, a total of 11 different aerosol products were comparatively analyzed using data collocated with ground-based aerosol observations from the Aerosol Robotic Network (AERONET) stations within the Multi-sensor Aerosol Products Sampling System (MAPSS, http://giovanni.gsfc.nasa.gov/mapss/ and http://giovanni.gsfc.nasa.gov/aerostat/). The analysis was performed by comparing quality-screened satellite aerosol optical depth or thickness (AOD or AOT) retrievals during 2006-2010 to available collocated AERONET measurements globally, regionally, and seasonally, and deriving a number of statistical measures of accuracy. We used a robust statistical approach to detect and remove possible outliers in the collocated data that can bias the results of the analysis. Overall, the proportion of outliers in each of the quality-screened AOD products was within 12%. Squared correlation coefficient (R2) values of the satellite AOD retrievals relative to AERONET exceeded 0.6, with R2 for most of the products exceeding 0.7 over land and 0.8 over ocean. Root mean square error (RMSE) values for most of the AOD products were within 0.15 over land and 0.09 over ocean. We have been able to generate global maps showing regions where the different products present advantages over the others, as well as the relative performance of each product over different landcover types. It was observed that while MODIS, MISR, and SeaWiFS provide accurate retrievals over most of the landcover types, multi-angle capabilities make MISR the only sensor to retrieve reliable AOD over barren and snow / ice surfaces. Likewise, active sensing enables CALIOP to retrieve aerosol properties over bright-surface shrublands more accurately than the other sensors, while POLDER, which is the only one of the sensors capable of measuring polarized aerosols, outperforms other sensors in

  20. Measurement of the sea surface wind speed and direction by an airborne microwave radar altimeter

    Energy Technology Data Exchange (ETDEWEB)

    Nekrassov, A. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Hydrophysik

    2001-07-01

    A pilot needs operational information about wind over sea as well as wave height to provide safety of a hydroplane landing on water. Near-surface wind speed and direction can be obtained with an airborne microwave scatterometer, radar designed for measuring the scatter characteristics of a surface. Mostly narrow-beam antennas are applied for such wind measurement. Unfortunately, a microwave narrow-beam antenna has considerable size that hampers its placing on flying apparatus. In this connection, a possibility to apply a conventional airborne radar altimeter as a scatterometer with a nadir-looking wide-beam antenna in conjunction with Doppler filtering for recovering the wind vector over sea is discussed, and measuring algorithms of sea surface wind speed and direction are proposed. The obtained results can be used for creation of an airborne radar system for operational measurement of the sea roughness characteristics and for safe landing of a hydroplane on water. (orig.)

  1. Eight years of wind measurements from scatterometer for wind resource mapping in the Mediterranean Sea

    DEFF Research Database (Denmark)

    Furevik, Birgitte R.; Sempreviva, Anna Maria; Cavaleri, Luigi

    2011-01-01

    that the scatterometer is able to provide similar long-term statistics as available from buoy data, such as annual and monthly wind indexes. Such statistics is useful to give an overview of the climatology in the different areas. The correlation between QuikScat and in situ observations is degraded towards the coast...

  2. Open access wind tunnel measurements of a downwind free yawing wind turbine

    DEFF Research Database (Denmark)

    Verelst, David Robert; Larsen, Torben J.; van Wingerden, Jan-Willem

    2016-01-01

    A series of free yawing wind tunnel experiments was held in the Open Jet Facility (OJF) of the TU Delft. The ≈ 300 W turbine has three blades in a downwind configuration and is optionally free to yaw. Different 1.6m diameter rotor configurations are tested such as blade flexibility and sweep...

  3. Wind atlas for South Africa: wind measurements and micro-scale modelling

    CSIR Research Space (South Africa)

    Szewczuk, S

    2010-08-01

    Full Text Available Africa is intended to accelerate the investment in wind energy in South Africa. This is in line with government’s objectives of reducing green house gases and diversifying our energy supply and also developing human capacity to support the emerging...

  4. Accounting for the speed shear in wind turbine power performance measurement

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, R.

    2010-04-15

    The power curve of a wind turbine is the primary characteristic of the machine as it is the basis of the warranty for it power production. The current IEC standard for power performance measurement only requires the measurement of the wind speed at hub height and the air density to characterise the wind field in front of the turbine. However, with the growing size of the turbine rotors during the last years, the effect of the variations of the wind speed within the swept rotor area, and therefore of the power output, cannot be ignored any longer. Primary effects on the power performance are from the vertical wind shear and the turbulence intensity. The work presented in this thesis consists of the description and the investigation of a simple method to account for the wind speed shear in the power performance measurement. Ignoring this effect was shown to result in a power curve dependant on the shear condition, therefore on the season and the site. It was then proposed to use an equivalent wind speed accounting for the whole speed profile in front of the turbine. The method was first tested with aerodynamic simulations of a multi-megawatt wind turbine which demonstrated the decrease of the scatter in the power curve. A power curve defined in terms of this equivalent wind speed would be less dependant on the shear than the standard power curve. The equivalent wind speed method was then experimentally validated with lidar measurements. Two equivalent wind speed definitions were considered both resulting in the reduction of the scatter in the power curve. As a lidar wind profiler can measure the wind speed at several heights within the rotor span, the wind speed profile is described with more accuracy than with the power law model. The equivalent wind speed derived from measurements, including at least one measurement above hub height, resulted in a smaller scatter in the power curve than the equivalent wind speed derived from profiles extrapolated from measurements

  5. Simultaneous measurements of the thermospheric wind profile at three separate positions in the dusk auroral oval

    International Nuclear Information System (INIS)

    Mikkelsen, I.S.; Friis-Christensen, E.; Larsen, M.F.; Kelley, M.C.; Vickrey, J.; Meriwether, J.; Shih, P.

    1987-01-01

    On March 20, 1985, two rockets were launched from Soendre Stroemfjord, Greenland, into the dusk auroral oval. Three trimethyl aluminium trails were released to measure the neutral wind profiles between 95 and 190 km of altitude at two points separated by 190 km normal to the invariant latitude circles and at a third point separated from the first two by 300 km along the invariant latitude circles. Two barium/strontium clouds were released at 250 km of altitude, extending two of the neutral wind profiles to this altitude. In the E region the tip of the wind vector traced an ellipse as a function of increasing altitude with maximum wind speeds of 100-150 m/s in the southeastward and northwestward directions. The F region winds were southward with speeds of 100-200 m/s. The zonal wind component between 115 and 140 km of altitude had a horizontal gradient in the southeastward direction, whereas the meridional wind component at the same heights was constant over the spatial extent covered by the measurements. The authors interpret the observed E region wind field as being part of a gravity wave with a period of 3 hours as estimated from the ellipticity of the wind hodograms. The wind vectors rotated 540 degree clockwise with increasing height, indicating that the wave energy is propagating upward. The Fabry-Perot interferometer at Soendre Stroemfjord was first able to detect the F region winds 45 min after the releases and measured winds of 100-400 m/s mainly in the southeastward or antisunward direction. The geomagnetic conditions were quiet, with Kp not exceeding 2 for the 24 hours preceding the experiment. The incoherent scatter radar at Soendre Stroemfjord observed a contracted plasma convection pattern associated with positive B y and B z components of the interplanetary magnetic field

  6. Turbine-blade tip clearance and tip timing measurements using an optical fiber bundle sensor

    Science.gov (United States)

    Garcia, Iker; Beloki, Josu; Zubia, Joseba; Durana, Gaizka; Aldabaldetreku, Gotzon

    2013-04-01

    Traditional limitations of capacitive, inductive or discharging probe sensor for tip timing and tip clearance measurements are overcome by reflective intensity modulated optical fiber sensors. This paper presents the signals and results corresponding to a one stage turbine rig which rotor has 146 blades, obtained from a transonic wind-tunnel test. The probe is based on a trifurcated bundle of optical fibers that is mounted on turbine casing. It is composed of a central illuminating fiber that guides the light from a laser to the turbine blade, and two concentric rings of receiving fibers that collect the reflected light. Two photodetectors turn this reflected light signal from the receiving rings into voltage. The electrical signals are acquired and saved by a high-sample-rate oscilloscope. In tip clearance calculations the ratio of the signals provided by each ring of receiving fibers is evaluated and translated into distance. In the case of tip timing measurements, only one of the signals is considered to get the arrival time of the blade. The differences between the real and theoretical arrival times of the blades are used to obtain the deflections amplitude. The system provides the travelling wave spectrum, which presents the average vibration amplitude of the blades at a certain nodal diameter. The reliability of the results in the turbine rig testing facilities suggests the possibility of performing these measurements in real turbines under real working conditions.

  7. Magneto-optic Doppler analyzer: a new instrument to measure mesopause winds

    Science.gov (United States)

    Williams, Bifford P.; Tomczyk, Steven

    1996-11-01

    The magneto-optic Doppler analyzer (MODA) is a new type of passive optical instrument that one can use to measure the Doppler shift of the sodium nightglow emitted at approximately 91 km near the mesopause. From this measurement, horizontal wind signatures are inferred. The MODA is based on a sodium vapor magneto-optic filter that provides inherent wavelength stability at a low cost. The instrument has been used to take nightly zonal and meridional wind measurements since October 1994 at Niwot Ridge, Colorado (40 N, 105 W). We obtained an internally consistent wind signal and measured the semidiurnal tide for several seasons.

  8. Microcontroller-based data logging instrumentation system for wind ...

    African Journals Online (AJOL)

    In this study, a microcontroller based data logger for measuring wind speed and wind direction has been designed. The designed system uses the Atmel microcontroller family which consists of sensor inputs, a microcontroller and a data storage device. The system was designed and developed to measure the wind speed ...

  9. Sensorized toys for measuring manipulation capabilities of infants at home.

    Science.gov (United States)

    Passetti, Giovanni; Cecchi, Francesca; Baldoli, Ilaria; Sgandurra, Giuseppina; Beani, Elena; Cioni, Giovanni; Laschi, Cecilia; Dario, Paolo

    2015-01-01

    Preterm infants, i.e. babies born after a gestation period shorter than 37 weeks, spend less time exploring objects. The quantitative measurement of grasping actions and forces in infants can give insights on their typical or atypical motor development. The aim of this work was to test a new tool, a kit of sensorized toys, to longitudinally measure, monitor and promote preterm infants manipulation capabilities with a purposive training in an ecological environment. This study presents preliminary analysis of grasping activity. Three preterm infants performed 4 weeks of daily training at home. Sensorized toys with embedded pressure sensors were used as part of the training to allow quantitative analysis of grasping (pressure and acceleration applied to toys while playing). Each toy was placed on the midline, while the infant was in supine position. Preliminary data show differences in the grasping parameters in relation to infants age and the performed daily training. Ongoing clinical trial will allow a full validation of this new tool for promoting object exploration in preterm infants.

  10. Coupling of the solar wind to measures of magnetic activity

    International Nuclear Information System (INIS)

    McPherron, R.L.; Fay, R.A.; Garrity, C.R.; Bargatze, L.F.; Baker, D.N.; Clauer, C.R.; Searls, C.

    1984-01-01

    The technique of linear prediction filtering has been used to generate empirical response functions relating the solar wind electric field to the most frequently used magnetic indices, AL, AU, Dst and ASYM. Two datasets, one from 1967-1968 and one from 1973-1974, provided the information needed to calculate the empirical response functions. These functions have been convolved with solar wind observations obtained during the IMS to predict the indices. These predictions are compared with the observed indices during two, three-day intervals studied extensively by participants in the CDAW-6 workshop. Differences between the observed and predicted indices are discussed in terms of the linear assumption and in terms of physical processes other than direct solar wind-magnetosphere interaction

  11. Acoustic noise measurements on a wind turbine performed in the frame of the NIWT round robin

    International Nuclear Information System (INIS)

    Van der Borg, N.J.C.M.; Vink, P.W.

    1996-11-01

    A round robin acoustic measurement campaign has been performed by five project partners using one and the same wind turbine (WT). The measurement procedure for the round robin exercise was agreed to be in compliance with the IEA-recommended practices on WT-noise emission measurements and the measured characteristics were agreed to be the apparent sound power level and the tonality, both measured at the reference measurement position. The measurements performed by ECN resulted in an A-weighted sound power level of the TACKE TW500/37 wind turbine in Hooksiel, Germany, of 95.8 dB(A) at a wind speed of 5.5 m/s at reference conditions. The tonality assessment of the sound pressure at 50 m down wind of the turbine resulted in a difference between the maximum tone level and the masking noise level of 2.4 dB. This characterizes the noise as 'prominent'. 2 refs

  12. Use of Smart Sensors in the Measurement of Power Quality

    Directory of Open Access Journals (Sweden)

    A. Moreno-Muñoz

    2008-03-01

    Full Text Available Today’s businesses depend heavily on electrical services for lighting, general power, computer hardware and communications hardware. With the generalized use of sophisticated electronic devices, industries are shifting toward almost entirely electronic IT systems. PQ events are of increasing concern for the economy because today’s equipment, particularly computers and automated manufacturing devices, is highly sensitive to such imperfections. Traditionally the control and supervision of a plant distribution network has mainly been focused on the protection of the network. Relatively little attention has been focused on the quality of the electrical energy. Metering technologies and communications systems have advanced to enable the development of web-based sensors. Power Quality is one area where these smart sensors can be very valuable. This paper investigates the challenges and possibilities in the development of distributed PQ measurement systems. This paper describes the challenges and lessons learned from this work.

  13. Discovery Mondays: 'Sensors, or the art of measuring limits'

    CERN Document Server

    2006-01-01

    The gigantic LHC machine and experiments will be teeming with minuscule sensors like this one, capable of measuring the tiniest of phenomena. In their study of the infinitesimally small, CERN's physicists, engineers and technicians work at the highest levels of precision. To ensure maximum performance, the most sensitive accelerator and detector components have to be positioned with razor-sharp precision. Detector components, for instance, sometimes need to be aligned to the nearest thousandth of a millimetre! The positioning of the LHC beam is another crucial operation requiring similarly phenomenal precision. Come to the next Discovery Monday and see how different types of sensors are used to achieve the required degrees of precision. The Hydrostatic Levelling System (HLS), for instance, relies on the same principle of communicating vessels that was already employed in antiquity for the construction of aqueducts, bridges and other edifices. You will discover the instrumentation that makes it possible to ...

  14. Two years of wind-lidar measurements at an Italian Mediterranean Coastal Site

    DEFF Research Database (Denmark)

    Gullí, D.; Avolio, E.; Calidonna, C. R.

    2017-01-01

    Reliable measurements of vertical profiles of wind speed and direction are needed for testing models and methodologies of use for wind energy assessment. In particular, modelling complex terrain such as coastal areas is challenging due to the coastal discontinuity that is not accurately resolved...... in mesoscale numerical model. Here, we present a unique database from a coastal site in South Italy (middle of the Mediterranean area) where vertical profiles of wind speed and direction have been collected during a two-year period from a wind-lidar ZEPHIR-300® at a coastal-suburban area. We show an overview...

  15. LONG-TERM TRENDS IN THE SOLAR WIND PROTON MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Heather A.; McComas, David J. [Southwest Research Institute, San Antonio, TX (United States); DeForest, Craig E. [Southwest Research Institute, Boulder, CO (United States)

    2016-11-20

    We examine the long-term time evolution (1965–2015) of the relationships between solar wind proton temperature ( T {sub p}) and speed ( V {sub p}) and between the proton density ( n {sub p}) and speed using OMNI solar wind observations taken near Earth. We find a long-term decrease in the proton temperature–speed ( T {sub p}– V {sub p}) slope that lasted from 1972 to 2010, but has been trending upward since 2010. Since the solar wind proton density–speed ( n {sub p}– V {sub p}) relationship is not linear like the T {sub p}– V {sub p} relationship, we perform power-law fits for n {sub p}– V {sub p}. The exponent (steepness in the n {sub p}– V {sub p} relationship) is correlated with the solar cycle. This exponent has a stronger correlation with current sheet tilt angle than with sunspot number because the sunspot number maxima vary considerably from cycle to cycle and the tilt angle maxima do not. To understand this finding, we examined the average n {sub p} for different speed ranges, and found that for the slow wind n {sub p} is highly correlated with the sunspot number, with a lag of approximately four years. The fast wind n {sub p} variation was less, but in phase with the cycle. This phase difference may contribute to the n {sub p}– V {sub p} exponent correlation with the solar cycle. These long-term trends are important since empirical formulas based on fits to T {sub p} and V {sub p} data are commonly used to identify interplanetary coronal mass ejections, but these formulas do not include any time dependence. Changes in the solar wind density over a solar cycle will create corresponding changes in the near-Earth space environment and the overall extent of the heliosphere.

  16. Wind power in the Danish liberalised power market-Policy measures, price impact and investor incentives

    International Nuclear Information System (INIS)

    Munksgaard, Jesper; Morthorst, Poul Erik

    2008-01-01

    Wind power has a strong position at the Danish electricity market, mainly caused by high feed-in tariffs in the 1990s. Investments in new wind-power installations on land, however, have declined dramatically after the Danish electricity market was liberalised in 1999. First, the paper describes how policy measures directed towards wind power have been redesigned to match the liberalised market. Then, we estimate the impact of the redesigned tariffs on the electricity prices. Finally, we assess whether the new tariffs make an incentive to invest in wind power. The paper concludes that the new tariffs not by itself make evidence for the actual Danish recession in new wind-power installations after the electricity reform. The main causes could include a combination of problems in spatial planning, high risk aversion of new wind turbine investors and perhaps more favourable support schemes in other countries

  17. Predicting Atmospheric Ionization and Excitation by Precipitating SEP and Solar Wind Protons Measured By MAVEN

    Science.gov (United States)

    Jolitz, Rebecca; Dong, Chuanfei; Lee, Christina; Lillis, Rob; Brain, David; Curry, Shannon; Halekas, Jasper; Bougher, Stephen W.; Jakosky, Bruce

    2017-10-01

    Precipitating energetic particles ionize and excite planetary atmospheres, increasing electron content and producing aurora. At Mars, the solar wind and solar energetic particles (SEPs) can precipitate directly into the atmosphere because solar wind protons can charge exchange to become neutral and pass the magnetosheath, and SEPs are sufficiently energetic to cross the magnetosheath unchanged. We will compare ionization and Lyman alpha emission rates for solar wind and SEP protons during nominal solar activity and a CME shock front impact event on May 16 2016. We will use the Atmospheric Scattering of Protons and Energetic Neutrals (ASPEN) model to compare excitation and ionization rates by SEPs and solar wind protons currently measured by the SWIA (Solar Wind Ion Analyzer) and SEP instruments aboard the MAVEN spacecraft. Results will help quantify how SEP and solar wind protons influence atmospheric energy deposition during solar minimum.

  18. Effects of finite aspect ratio on wind turbine airfoil measurements

    DEFF Research Database (Denmark)

    Kiefer, Janik; Miller, Mark A.; Hultmark, Marcus

    2016-01-01

    Wind turbines partly operate in stalled conditions within their operational cycle. To simulate these conditions, it is also necessary to obtain 2-D airfoil data in terms of lift and drag coefficients at high angles of attack. Such data has been obtained previously, but often at low aspect ratios...... and only barely past the stall point, where strong wall boundary layer influence is expected. In this study, the influence of the wall boundary layer on 2D airfoil data, especially in the post stall domain, is investigated. Here, a wind turbine airfoil is tested at different angles of attack and with two...

  19. Tracking of smokestack and cooling tower plumes using wind measurements at different levels

    International Nuclear Information System (INIS)

    Miller, R.L.; Patrinos, A.A.N.

    1980-08-01

    Relationships between cooling tower and smokestack plumes at the Bowen Electric Generating Plant in northwestern Georgia and wind direction measurements at levels from the surface at 850 mb (approx. 1.5 km) are examined. The wind measurements play an important role in estimating plume directions which in turn are utilized to establish control and target (upwind and downwind) areas for a study of plant-induced precipitation modification. Fifty-two plume observations were made during a three week period in December 1979. Results indicate that a windset (4.5 km from the plant) mounted at a level approximating that of the cooling tower plume is a better predictor of plume direction than surface windsets (1.0 km from the plant) or 850 mb level winds. However, an apparent topographical influence on the wind direction measurements at the plume-level windset site somewhat limits its plume tracking capability, at least for ambient winds from the SW quadrant

  20. Real-Time Unsteady Loads Measurements Using Hot-Film Sensors

    Science.gov (United States)

    Mangalam, Arun S.; Moes, Timothy R.

    2004-01-01

    Several flight-critical aerodynamic problems such as buffet, flutter, stall, and wing rock are strongly affected or caused by abrupt changes in unsteady aerodynamic loads and moments. Advanced sensing and flow diagnostic techniques have made possible simultaneous identification and tracking, in realtime, of the critical surface, viscosity-related aerodynamic phenomena under both steady and unsteady flight conditions. The wind tunnel study reported here correlates surface hot-film measurements of leading edge stagnation point and separation point, with unsteady aerodynamic loads on a NACA 0015 airfoil. Lift predicted from the correlation model matches lift obtained from pressure sensors for an airfoil undergoing harmonic pitchup and pitchdown motions. An analytical model was developed that demonstrates expected stall trends for pitchup and pitchdown motions. This report demonstrates an ability to obtain unsteady aerodynamic loads in real time, which could lead to advances in air vehicle safety, performance, ride-quality, control, and health management.

  1. A novel integrated multifunction micro-sensor for three-dimensional micro-force measurements.

    Science.gov (United States)

    Wang, Weizhong; Zhao, Yulong; Qin, Yafei

    2012-01-01

    An integrated multifunction micro-sensor for three-dimensional micro-force precision measurement under different pressure and temperature conditions is introduced in this paper. The integrated sensor consists of three kinds of sensors: a three-dimensional micro-force sensor, an absolute pressure sensor and a temperature sensor. The integrated multifunction micro-sensor is fabricated on silicon wafers by micromachining technology. Different doping doses of boron ion, placement and structure of resistors are tested for the force sensor, pressure sensor and temperature sensor to minimize the cross interference and optimize the properties. A glass optical fiber, with a ladder structure and sharp tip etched by buffer oxide etch solution, is glued on the micro-force sensor chip as the tactile probe. Experimental results show that the minimum force that can be detected by the force sensor is 300 nN; the lateral sensitivity of the force sensor is 0.4582 mV/μN; the probe length is linearly proportional to sensitivity of the micro-force sensor in lateral; the sensitivity of the pressure sensor is 0.11 mv/KPa; the sensitivity of the temperature sensor is 5.836 × 10(-3) KΩ/°C. Thus it is a cost-effective method to fabricate integrated multifunction micro-sensors with different measurement ranges that could be used in many fields.

  2. A Novel Integrated Multifunction Micro-Sensor for Three-Dimensional Micro-Force Measurements

    Directory of Open Access Journals (Sweden)

    Yafei Qin

    2012-03-01

    Full Text Available An integrated multifunction micro-sensor for three-dimensional micro-force precision measurement under different pressure and temperature conditions is introduced in this paper. The integrated sensor consists of three kinds of sensors: a three-dimensional micro-force sensor, an absolute pressure sensor and a temperature sensor. The integrated multifunction micro-sensor is fabricated on silicon wafers by micromachining technology. Different doping doses of boron ion, placement and structure of resistors are tested for the force sensor, pressure sensor and temperature sensor to minimize the cross interference and optimize the properties. A glass optical fiber, with a ladder structure and sharp tip etched by buffer oxide etch solution, is glued on the micro-force sensor chip as the tactile probe. Experimental results show that the minimum force that can be detected by the force sensor is 300 nN; the lateral sensitivity of the force sensor is 0.4582 mV/μN; the probe length is linearly proportional to sensitivity of the micro-force sensor in lateral; the sensitivity of the pressure sensor is 0.11 mv/KPa; the sensitivity of the temperature sensor is 5.836 × 10−3 KΩ/°C. Thus it is a cost-effective method to fabricate integrated multifunction micro-sensors with different measurement ranges that could be used in many fields.

  3. Wind tunnel measurements of the urban boundary layer development over a historical district in Italy

    NARCIS (Netherlands)

    Ricci, A.; Burlando, M.; Freda, A.; Repetto, M.P.

    2017-01-01

    This paper presents the results of an experimental study aimed at investigating the urban boundary layer in a district of Livorno city, in Tuscany. The wind flow over this area has been measured in the wind tunnel of the University of Genova using a physical model in scale 1:300. Two sets of

  4. The Coincidence Tracker: Electronic Equipment for a Time-of-Flight Wind-Speed Measurement System

    DEFF Research Database (Denmark)

    Fog, Christian

    1982-01-01

    The electronic part of a laser-beam measuring system for wind velocity is described. Pulses of light scattered from aerosols are treated, first in a pair of adaptive filters, then in a tracker that calculates the wind velocity on-line while applying some knowledge about the velocity to be expected...

  5. Bite force measurement based on fiber Bragg grating sensor

    Science.gov (United States)

    Padma, Srivani; Umesh, Sharath; Asokan, Sundarrajan; Srinivas, Talabattula

    2017-10-01

    The maximum level of voluntary bite force, which results from the combined action of muscle of mastication, joints, and teeth, i.e., craniomandibular structure, is considered as one of the major indicators for the functional state of the masticatory system. Measurement of voluntary bite force provides useful data for the jaw muscle function and activity along with assessment of prosthetics. This study proposes an in vivo methodology for the dynamic measurement of bite force employing a fiber Bragg grating (FBG) sensor known as bite force measurement device (BFMD). The BFMD developed is a noninvasive intraoral device, which transduces the bite force exerted at the occlusal surface into strain variations on a metal plate. These strain variations are acquired by the FBG sensor bonded over it. The BFMD developed facilitates adjustment of the distance between the biting platform, which is essential to capture the maximum voluntary bite force at three different positions of teeth, namely incisor, premolar, and molar sites. The clinically relevant bite forces are measured at incisor, molar, and premolar position and have been compared against each other. Furthermore, the bite forces measured with all subjects are segregated according to gender and also compared against each other.

  6. Measurement of Sediment Deposition Rates using an Optical Backscatter Sensor

    Science.gov (United States)

    Ridd, P.; Day, G.; Thomas, S.; Harradence, J.; Fox, D.; Bunt, J.; Renagi, O.; Jago, C.

    2001-02-01

    An optical method for measuring siltation of sediment has been developed using an optical fibre backscatter (OBS) nephelometer. Sediment settling upon the optical fibre sensor causes an increase in the backscatter reading which can be related to the settled sediment surface density (SSSD) as measured in units of mg cm -2. Calibration and laboratory tests indicate that the resolution of measurements of SSSD is 0·01 mg cm -2and an accuracy of 5% in still water. In moving water it is more difficult to determine the accuracy of the method because other methods with suitable resolution are unavailable. However, indirect methods using measurements of changing suspended sediment concentration in a ring flume, indicate that the OBS method under-predicts deposition. The series of siltation from three field sites are presented. This sensor offers considerable advances over other methods of measuring settling because time series of settling may be taken and thus settling events may be related to other hydrodynamic parameters such as wave climate and currents.

  7. A new oil debris sensor for online condition monitoring of wind turbine gearboxes

    DEFF Research Database (Denmark)

    Wang, Chao; Liu, Hui; Liu, Xiao

    2015-01-01

    Online Condition Monitoring (CM) is a key technology for the Operation and Maintenance (O&M) of wind turbines. Lubricating oil is the blood of the wind turbine gearbox. Metal debris in lubricating oil contains abundant information regarding the ageing and wear/damage of mechanical transmission sy...

  8. Statistical Analysis and Comparison of Harmonics Measured in Offshore Wind Farms

    DEFF Research Database (Denmark)

    Kocewiak, Lukasz Hubert; Hjerrild, Jesper; Bak, Claus Leth

    2011-01-01

    The paper shows statistical analysis of harmonic components measured in different offshore wind farms. Harmonic analysis is a complex task and requires many aspects, such as measurements, data processing, modeling, validation, to be taken into consideration. The paper describes measurement process...... and shows sophisticated analysis on representative harmonic measurements from Avedøre Holme, Gunfleet Sands and Burbo Bank wind farms. The nature of generation and behavior of harmonic components in offshore wind farms clearly presented and explained based on probabilistic approach. Some issues regarding...... commonly applied standards are also put forward in the discussion. Based on measurements and data analysis it is shown that a general overview about wind farm harmonic behaviour cannot be fully observed only based on single-value measurements as suggested in the standards but using more descriptive...

  9. Brief communication: Structural monitoring for lifetime extension of offshore wind monopiles: can strain measurements at one level tell us everything?

    Directory of Open Access Journals (Sweden)

    L. Ziegler

    2017-09-01

    Full Text Available Operators need accurate knowledge on structural reserves to decide about lifetime extension of offshore wind turbines. Load monitoring enables us to directly compare design loads with real loading histories of the support structure in order to calculate its remaining useful lifetime. Monitoring of every hot spot is technically and financially not feasible. This paper presents a novel idea for load monitoring of monopiles. It requires strain measurements at only one level convenient for sensor installation, such as tower bottom. Measurements are converted into damage equivalent loads for 10 min time intervals. Damage equivalent loads are extrapolated to other locations of the structure with a simulation model and statistical algorithm. For this, structural loads at all locations of the monopile are calculated with aero-hydro-elastic software and updated finite element models. Damage equivalent loads at unmeasured locations are predicted from the simulation results with a k-nearest neighbor regression algorithm. The extrapolation was tested with numerical simulations of an 8 MW offshore wind turbine. Results show that damage can be predicted with an error of 1–3 % if this is done conditional on mean wind speed, which is very promising. The load monitoring concept is simple, cheap and easy to implement. This makes it ideal for making decisions on lifetime extension of monopiles.

  10. pH measurements of FET-based (bio)chemical sensors using portable measurement system.

    Science.gov (United States)

    Voitsekhivska, T; Zorgiebel, F; Suthau, E; Wolter, K-J; Bock, K; Cuniberti, G

    2015-01-01

    In this study we demonstrate the sensing capabilities of a portable multiplex measurement system for FET-based (bio)chemical sensors with an integrated microfluidic interface. We therefore conducted pH measurements with Silicon Nanoribbon FET-based Sensors using different measurement procedures that are suitable for various applications. We have shown multiplexed measurements in aqueous medium for three different modes that are mutually specialized in fast data acquisition (constant drain current), calibration-less sensing (constant gate voltage) and in providing full information content (sweeping mode). Our system therefore allows surface charge sensing for a wide range of applications and is easily adaptable for multiplexed sensing with novel FET-based (bio)chemical sensors.

  11. Analysis of measurements on wind turbine arrays. Vol. 1

    International Nuclear Information System (INIS)

    Hoeg, E.

    1990-12-01

    In 1989 a Danish electric power company initiated an analysis of eight wind turbine arrays. Data from this project is presented together with the explained results of the analyses and the output variations for individual arrays and for systems within the arrays. The models for prognosis are compared and evaluated in order to find that which is most effective. (AB)

  12. Nutrient losses by wind and water, measurements and modelling

    NARCIS (Netherlands)

    Visser, S.M.; Stroosnijder, L.; Chardon, W.J.

    2005-01-01

    In the Sahelian zone of West-Africa, erosion by both wind and water causes a serious decline in fertility of the already low fertile soils. Despite the fact that the flow of nutrients has been intensively investigated by the use of nutrient balances, little attention has been paid to the

  13. The efficiency of windbreaks on the basis of wind field and optical porosity measurement

    Directory of Open Access Journals (Sweden)

    Tomáš Středa

    2008-01-01

    Full Text Available Windbreaks have been used for many years to reduce wind speed as a wind-erosion control mea­su­re. To assessment of windbreak efficiency two main parameters are using: height of windbreak (H and aerodynamic porosity. In South Moravian Region the total area of windbreaks is approximately 1200 ha. For purposes of horizontal profile measurement of wind speed and wind direction windbreaks with various spices composition, age and construction in cadastral territory Suchá Loz and Micmanice were chosen. Windbreak influence on horizontal wind profile was found out in distance of 50, 100, 150 and 200 m in front and behind windbreak in two-meter height above surface. For the optical porosity measurement the ImageTool program was used. The wind field measurement results of windbreak in Suchá Loz cadastral shows limited effect of windbreak on wind speed. The windbreak is created mainly by Canadian poplars (Populus × canadensis. In dependence on main species foliage stage the effect of windbreak was obvious on leeward side to distance of 100–150 m (c. 5–7 H. Average optical porosity of windbreak in Suchá Loz was 50% (April. Reduction of average wind speed was about 17% maximally in this stage. Optical porosity was 20% and wind speed reduction was about 37% during second measurement (October. The second monitored windbreak (Micmanice had a significant influence on wind speed even to the maximal measured distance (200 m, c. 14 H. This windbreak crea­ted mainly by Acer sp. and Fraxinus excelsior reduced the wind speed about 64%. During first measurement (May the optical porosity of 20% and maximal wind speed reduction of 64% were assessed. For optical porosity of 21% (October the wind speed reduction was about 55%. Close relation between optical porosity and wind speed reduction was found out by statistical evaluation. Correlation coefficient regardless locality for distance of 50 m was −0.80, 100 m −0.92, 150 m −0.76 and for distance of 200 m

  14. A Novel Stretch Sensor to Measure Venous Hemodynamics

    Directory of Open Access Journals (Sweden)

    Syrpailyne Wankhar

    2018-07-01

    Full Text Available Chronic venous insufficiency is a debilitating condition causing varicose veins and venous ulcers. The pathophysiology includes reflux and venous obstruction. The diagnosis is often made by clinical examination and confirmed by Venous Doppler studies. Plethysmography helps to quantitatively examine the reflux and diagnose the burden of deep venous pathology to better understand venous hemodynamics, which is not elicited by venous duplex examination alone. However, most of these tests are qualitative, expensive, and not easily available. In this paper, we demonstrate the potential use of a novel stretch sensor in the assessment of venous hemodynamics during different maneuvers by measuring the change in calf circumference. We designed the stretch sensor by using semiconductor strain gauges pasted onto a small metal bar to form a load cell. The elastic and Velcro material attached to the load cell form a belt. It converts the change in limb circumference to a proportional tension (force of distension when placed around the calf muscle. We recorded the change in limb circumference from arrays of stretch sensors by using an in-house data acquisition system. We calculated the venous volume (VV, venous filling index (VFI, ejection fraction (EF and residual venous volume (RVV on two normal subjects and on two patients to assess venous hemodynamics. The values (VV > 60 ml, VFI 60%, RVV 2ml/s, EF 35% in patients were comparable to those reported in the literature.

  15. Time Synchronized Wireless Sensor Network for Vibration Measurement

    Science.gov (United States)

    Uchimura, Yutaka; Nasu, Tadashi; Takahashi, Motoichi

    Network based wireless sensing has become an important area of research and various new applications for remote sensing are expected to emerge. One of the promising applications is structural health monitoring of building or civil engineering structure and it often requires vibration measurement. For the vibration measurement via wireless network, time synchronization is indispensable. In this paper, we introduce a newly developed time synchronized wireless sensor network system. The system employs IEEE 802.11 standard based TSF counter and sends the measured data with the counter value. TSF based synchronization enables consistency on common clock among different wireless nodes. We consider the scale effect on the synchronization accuracy and the effect is evaluated by stochastic analysis and simulation studies. A new wireless sensing system is developed and the hardware and software specifications are shown. The experiments are conducted in a reinforced concrete building and results show good performance enough for vibration measurement purpose.

  16. Aerodynamical errors on tower mounted wind speed measurements due to the presence of the tower

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, H. [Uppsala Univ. (Sweden). Dept. of Meteorology; Dahlberg, J.Aa. [Aeronautical Research Inst. of Sweden, Bromma (Sweden)

    1996-12-01

    Field measurements of wind speed from two lattice towers showed large differences for wind directions where the anemometers of both towers should be unaffected by any upstream obstacle. The wind speed was measured by cup anemometers mounted on booms along the side of the tower. A simple wind tunnel test indicates that the boom, for the studied conditions, could cause minor flow disturbances. A theoretical study, by means of simple 2D flow modelling of the flow around the mast, demonstrates that the tower itself could cause large wind flow disturbances. A theoretical study, based on simple treatment of the physics of motion of a cup anemometer, demonstrates that a cup anemometer is sensitive to velocity gradients across the cups and responds clearly to velocity gradients in the vicinity of the tower. Comparison of the results from the theoretical study and field tests show promising agreement. 2 refs, 8 figs

  17. Reliability measures for indexed semi-Markov chains applied to wind energy production

    International Nuclear Information System (INIS)

    D'Amico, Guglielmo; Petroni, Filippo; Prattico, Flavio

    2015-01-01

    The computation of the dependability measures is a crucial point in many engineering problems as well as in the planning and development of a wind farm. In this paper we address the issue of energy production by wind turbines by using an indexed semi-Markov chain as a model of wind speed. We present the mathematical model, the data and technical characteristics of a commercial wind turbine (Aircon HAWT-10kW). We show how to compute some of the main dependability measures such as reliability, availability and maintainability functions. We compare the results of the model with real energy production obtained from data available in the Lastem station (Italy) and sampled every 10 min. - Highlights: • Semi-Markov models. • Time series generation of wind speed. • Computation of availability, reliability and maintainability.

  18. Diurnal evolution of wind structure and data availability measured by the DOE prototype radar system

    Science.gov (United States)

    Hirth, Brian D.; Schroeder, John L.; Guynes, Jerry G.

    2017-11-01

    A new Doppler radar prototype has been developed and deployed at Texas Tech University with a focus on enhancing the technologies’ capability to contribute to wind plant relevant complex flow measurements. In particular, improvements in data availability, total data coverage, and autonomous operation were targeted to enable contributions to a wider range of wind energy applications. Doppler radar offers rapid scan speeds, extended maximum range and excellent along-beam range resolution allowing for the simultaneous measurement of various wind phenomena ranging from regional and wind plant scales to inflow and wake flow assessment for an individual turbine. Data examples and performance improvements relative to a previous edition of the technology are presented, including insights into the influence of diurnal atmospheric stability evolution of wind structure and system performance.

  19. Spatial-temporal analysis of coherent offshore wind field structures measured by scanning Doppler-lidar

    Science.gov (United States)

    Valldecabres, L.; Friedrichs, W.; von Bremen, L.; Kühn, M.

    2016-09-01

    An analysis of the spatial and temporal power fluctuations of a simplified wind farm model is conducted on four offshore wind fields data sets, two from lidar measurements and two from LES under unstable and neutral atmospheric conditions. The integral length scales of the horizontal wind speed computed in the streamwise and the cross-stream direction revealed the elongation of the structures in the direction of the mean flow. To analyse the effect of the structures on the power output of a wind turbine, the aggregated equivalent power of two wind turbines with different turbine spacing in the streamwise and cross-stream direction is analysed at different time scales under 10 minutes. The fact of considering the summation of the power of two wind turbines smooths out the fluctuations of the power output of a single wind turbine. This effect, which is stronger with increasing spacing between turbines, can be seen in the aggregation of the power of two wind turbines in the streamwise direction. Due to the anti-correlation of the coherent structures in the cross-stream direction, this smoothing effect is stronger when the aggregated power is computed with two wind turbines aligned orthogonally to the mean flow direction.

  20. Atmospheric conditions measured by a wireless sensor network on the local scale

    Science.gov (United States)

    Lengfeld, K.; Ament, F.

    2010-09-01

    Atmospheric conditions close to the surface, like temperature, wind speed and humidity, vary on small scales because of surface heterogeneities. Therefore, the traditional measuring approach of using a single, highly accurate station is of limited representativeness for a larger domain, because it is not able to determine these small scale variabilities. However, both the variability and the domain averages are important information for the development and validation of atmospheric models and soil-vegetation-atmosphere-transfer (SVAT) schemes. Due to progress in microelectronics it is possible to construct networks of comparably cheap meteorological stations with moderate accuracy. Such a network provides data in high spatial and temporal resolution. The EPFL Lausanne developed such a network called SensorScope, consisting of low cost autonomous stations. Each station observes air and surface temperature, humidity, wind direction and speed, incoming solar radiation, precipitation, soil moisture and soil temperature and sends the data via radio communication to a base station. This base station forwards the collected data via GSM/GPRS to a central server. The first measuring campaign took place within the FLUXPAT project in August 2009. We deployed 15 stations as a twin transect near Jülich, Germany. To test the quality of the low cost sensors we compared two of them to more accurate reference systems. It turned out, that although the network sensors are not highly accurate, the measurements are consistent. Consequently an analysis of the pattern of atmospheric conditions is feasible. The transect is 2.3 km long and covers different types of vegetation and a small river. Therefore, we analyse the influence of different land surfaces and the distance to the river on meteorological conditions. For example, we found a difference in air temperature of 0.8°C between the station closest to and the station farthest from the river. The decreasing relative humidity with

  1. Wind measurements with SODAR during strong temperature inversions near the ground

    International Nuclear Information System (INIS)

    Thomas, P.; Vogt, S.

    1989-08-01

    SODAR (Sound Detection and Ranging) equipment has been increasingly used to measure vertical wind profiles with little expenditure in terms of staff, continuously over time and with a good spatial resolution. These informations serve as input variables for atmospheric transport and dispersion models, environmental monitoring of industrial facilities and, generally, for investigating a broad spectrum of meteorological phenomena. The SODAR principle has proved its suitability since long provided that the data recorded with SODAR have served to establish wind statistics valid for extended periods of time. At industrial sites potentially releasing substances prejudicial to health, e.g., chemical plants, nuclear power plants, etc., a SODAR must, moreover, be capable of measuring reliable the wind conditions also during short periods of release. This would, e.g., be important during accidental releases. Especially interesting situations for pollutant dispersion are distinct temperature inversions. It will be examined in this paper whether a SODAR is capable of measuring reliably the wind conditions also during those inversions. The selection of the situations of inversion as well as the direct intercomparison of data supplied by SODAR and conventional wind measuring instruments (anemometer and wind vane) are possible at the 200 m meteorological tower erected at the Karlsruhe Nuclear Research Center. The comparison between SODAR and the meteorological tower has shown that a SODAR is able to measure reliably the wind data also in situations characterized by strong ground-based and elevated inversions, respectively. (orig./KW) [de

  2. Tower Based Load Measurements for Individual Pitch Control and Tower Damping of Wind Turbines

    International Nuclear Information System (INIS)

    Kumar, A A; Hugues-Salas, O; Savini, B; Keogh, W

    2016-01-01

    The cost of IPC has hindered adoption outside of Europe despite significant loading advantages for large wind turbines. In this work we presented a method for applying individual pitch control (including for higher-harmonics) using tower-top strain gauge feedback instead of blade-root strain gauge feedback. Tower-top strain gauges offer hardware savings of approximately 50% in addition to the possibility of easier access for maintenance and installation and requiring a less specialised skill-set than that required for applying strain gauges to composite blade roots. A further advantage is the possibility of using the same tower-top sensor array for tower damping control. This method is made possible by including a second order IPC loop in addition to the tower damping loop to reduce the typically dominating 3P content in tower-top load measurements. High-fidelity Bladed simulations show that the resulting turbine spectral characteristics from tower-top feedback IPC and from the combination of tower-top IPC and damping loops largely match those of blade-root feedback IPC and nacelle- velocity feedback damping. Lifetime weighted fatigue analysis shows that the methods allows load reductions within 2.5% of traditional methods. (paper)

  3. Esopo: sEnsors and SOcial POllution measurements

    OpenAIRE

    Cozza, Vittoria; Guagliardi, Ilaria; Rubino, Michelangelo; Cozza, Raffaele; Martello, Alessandra; Picelli, Marco; Zhupa, Eustrat

    2015-01-01

    In the following we present the idea of a smart sensor distributed platform where users collect pollution measurements by simply placing a small smart device out of their office or home window, a device that interacts with their smartphones. They provide time-geolocalized information that, trough an app, will be made available to the community that will have the chance to control the pollution level and eventually share it on the most popular social networks along with the related user?s opin...

  4. Field campaign for the comparison of SOUSY radar wind measurements with rawinsonde and model data

    Directory of Open Access Journals (Sweden)

    H. Steinhagen

    Full Text Available A field campaign was carried out from 26 October to 7 November 1992, using the SOUSY-VHF radar and a mobile rawinsonde system installed and operated nearby to produce vertical wind profiles. The purpose of this campaign was to compare the two types of wind measurements with one another and with results from forecast models. Numerical algorithms were developed and applied to the radar data in order to eliminate random errors, correct for velocity aliasing, and calculate the effective zenith angle of the off-vertical beams. Differences between wind profiler data and rawinsonde or model results depend not only upon the errors of the different systems, but also on temporal and spatial variations of the wind field. Therefore, methods for the comparison of radar and rawinsonde data were developed which take into consideration these variations. The practical potential of these methods is demonstrated by comparisons of rawinsonde and radar wind profiles. The comparison of radar data and model output shows excellent agreement in the direction and in the speed of the wind at virtually all altitudes. An evaluation of the quality of wind profiler measurements is possible using the estimation of variance and variability of wind components.

  5. Field campaign for the comparison of SOUSY radar wind measurements with rawinsonde and model data

    Directory of Open Access Journals (Sweden)

    H. Steinhagen

    1994-07-01

    Full Text Available A field campaign was carried out from 26 October to 7 November 1992, using the SOUSY-VHF radar and a mobile rawinsonde system installed and operated nearby to produce vertical wind profiles. The purpose of this campaign was to compare the two types of wind measurements with one another and with results from forecast models. Numerical algorithms were developed and applied to the radar data in order to eliminate random errors, correct for velocity aliasing, and calculate the effective zenith angle of the off-vertical beams. Differences between wind profiler data and rawinsonde or model results depend not only upon the errors of the different systems, but also on temporal and spatial variations of the wind field. Therefore, methods for the comparison of radar and rawinsonde data were developed which take into consideration these variations. The practical potential of these methods is demonstrated by comparisons of rawinsonde and radar wind profiles. The comparison of radar data and model output shows excellent agreement in the direction and in the speed of the wind at virtually all altitudes. An evaluation of the quality of wind profiler measurements is possible using the estimation of variance and variability of wind components.

  6. Molecular force sensors to measure stress in cells

    International Nuclear Information System (INIS)

    Prabhune, Meenakshi; Rehfeldt, Florian; Schmidt, Christoph F

    2017-01-01

    Molecularly generated forces are essential for most activities of biological cells, but also for the maintenance of steady state or homeostasis. To quantitatively understand cellular dynamics in migration, division, or mechanically guided differentiation, it will be important to exactly measure stress fields within the cell and the extracellular matrix. Traction force microscopy and related techniques have been established to determine the stress transmitted from adherent cells to their substrates. However, different approaches are needed to directly assess the stress generated inside the cell. This has recently led to the development of novel molecular force sensors. In this topical review, we briefly mention methods used to measure cell-external forces, and then summarize and explain different designs for the measurement of cell-internal forces with their respective advantages and disadvantages. (topical review)

  7. Dynamic tire pressure sensor for measuring ground vibration.

    Science.gov (United States)

    Wang, Qi; McDaniel, James Gregory; Wang, Ming L

    2012-11-07

    This work presents a convenient and non-contact acoustic sensing approach for measuring ground vibration. This approach, which uses an instantaneous dynamic tire pressure sensor (DTPS), possesses the capability to replace the accelerometer or directional microphone currently being used for inspecting pavement conditions. By measuring dynamic pressure changes inside the tire, ground vibration can be amplified and isolated from environmental noise. In this work, verifications of the DTPS concept of sensing inside the tire have been carried out. In addition, comparisons between a DTPS, ground-mounted accelerometer, and directional microphone are made. A data analysis algorithm has been developed and optimized to reconstruct ground acceleration from DTPS data. Numerical and experimental studies of this DTPS reveal a strong potential for measuring ground vibration caused by a moving vehicle. A calibration of transfer function between dynamic tire pressure change and ground acceleration may be needed for different tire system or for more accurate application.

  8. Direct Embedding of Fiber-Optical Load Sensors into Wind Turbine Blades

    DEFF Research Database (Denmark)

    Glavind, Lars; Buggy, Stephen; Olesen, Ib S.

    Long Period Gratings were embedded into the adhesive utilized in the matrix of a wind turbine blade. The LPGs were subsequently subjected to temperature-testing in order to assess their performance, which illustrates good embedding capabilities....

  9. Compact 3D Wind Sensor for Unmanned Aerial Vehicles, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Accurate wide-area mapping of three-dimensional (3D) wind vectors plays an important role in our ability to understand climate processes, predict weather patterns...

  10. Multifunctional TENG for Blue Energy Scavenging and Self-Powered Wind-Speed Sensor

    KAUST Repository

    Xi, Yi; Guo, Hengyu; Zi, Yunlong; Li, Xiaogan; Wang, Jie; Deng, Jianan; Li, Shengming; Hu, Chenguo; Cao, Xia; Wang, Zhong Lin

    2017-01-01

    Triboelectric nanogenerator (TENG) has been considered to be a more effective technology to harvest various types of mechanic vibration energies such as wind energy, water energy in the blue energy, and so on. Considering the vast energy from

  11. Assessment and Optimization of Lidar Measurement Availability for Wind Turbine Control: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Davoust, S.; Jehu, A.; Bouillet, M.; Bardon, M.; Vercherin, B.; Scholbrock, A.; Fleming, P.; Wright, A.

    2014-05-01

    Turbine-mounted lidars provide preview measurements of the incoming wind field. By reducing loads on critical components and increasing the potential power extracted from the wind, the performance of wind turbine controllers can be improved [2]. As a result, integrating a light detection and ranging (lidar) system has the potential to lower the cost of wind energy. This paper presents an evaluation of turbine-mounted lidar availability. Availability is a metric which measures the proportion of time the lidar is producing controller-usable data, and is essential when a wind turbine controller relies on a lidar. To accomplish this, researchers from Avent Lidar Technology and the National Renewable Energy Laboratory first assessed and modeled the effect of extreme atmospheric events. This shows how a multirange lidar delivers measurements for a wide variety of conditions. Second, by using a theoretical approach and conducting an analysis of field feedback, we investigated the effects of the lidar setup on the wind turbine. This helps determine the optimal lidar mounting position at the back of the nacelle, and establishes a relationship between availability, turbine rpm, and lidar sampling time. Lastly, we considered the role of the wind field reconstruction strategies and the turbine controller on the definition and performance of a lidar's measurement availability.

  12. Equatorial F region neutral winds and shears near sunset measured with chemical release techniques

    Science.gov (United States)

    Kiene, A.; Larsen, M. F.; Kudeki, E.

    2015-10-01

    The period near sunset is a dynamic and critical time for the daily development of the equatorial nighttime ionosphere and the instabilities that occur there. It is during these hours that the preconditions necessary for the later development of Equatorial Spread F (ESF) plasma instabilities occur. The neutral dynamics of the sunset ionosphere are also of critical importance to the generation of currents and electric fields; however, the behavior of the neutrals is experimentally understood primarily through very limited single-altitude measurements or measurements that provide weighted altitude means of the winds as a function of time. To date, there have been very few vertically resolved neutral wind measurements in the F region at sunset. We present two sets of sounding rocket chemical release measurements, one from a launch in the Marshall Islands on Kwajalein atoll and one from Alcantara, Brazil. Analysis of the release motions has yielded vertically resolved neutral wind profiles that show both the mean horizontal winds and the vertical shears in the winds. In both experiments, we observe significant vertical gradients in the zonal wind that are unexpected by classical assumptions about the behavior of the neutral wind at these altitudes at sunset near the geomagnetic equator.

  13. A hybrid measure-correlate-predict method for long-term wind condition assessment

    International Nuclear Information System (INIS)

    Zhang, Jie; Chowdhury, Souma; Messac, Achille; Hodge, Bri-Mathias

    2014-01-01

    Highlights: • A hybrid measure-correlate-predict (MCP) methodology with greater accuracy is developed. • Three sets of performance metrics are proposed to evaluate the hybrid MCP method. • Both wind speed and direction are considered in the hybrid MCP method. • The best combination of MCP algorithms is determined. • The developed hybrid MCP method is uniquely helpful for long-term wind resource assessment. - Abstract: This paper develops a hybrid measure-correlate-predict (MCP) strategy to assess long-term wind resource variations at a farm site. The hybrid MCP method uses recorded data from multiple reference stations to estimate long-term wind conditions at a target wind plant site with greater accuracy than is possible with data from a single reference station. The weight of each reference station in the hybrid strategy is determined by the (i) distance and (ii) elevation differences between the target farm site and each reference station. In this case, the wind data is divided into sectors according to the wind direction, and the MCP strategy is implemented for each wind direction sector separately. The applicability of the proposed hybrid strategy is investigated using five MCP methods: (i) the linear regression; (ii) the variance ratio; (iii) the Weibull scale; (iv) the artificial neural networks; and (v) the support vector regression. To implement the hybrid MCP methodology, we use hourly averaged wind data recorded at five stations in the state of Minnesota between 07-01-1996 and 06-30-2004. Three sets of performance metrics are used to evaluate the hybrid MCP method. The first set of metrics analyze the statistical performance, including the mean wind speed, wind speed variance, root mean square error, and mean absolute error. The second set of metrics evaluate the distribution of long-term wind speed; to this end, the Weibull distribution and the Multivariate and Multimodal Wind Distribution models are adopted. The third set of metrics analyze

  14. Diagnostics of the Solar Wind and Global Heliosphere with Lyman-α Emission Measurements

    Science.gov (United States)

    Provornikova, E. P.; Izmodenov, V. V.; Laming, J. M.; Strachan, L.; Wood, B. E.; Katushkina, O. A.; Ko, Y.-K.; Tun Beltran, S.; Chakrabarti, S.

    2018-02-01

    We propose to develop an instrument measuring full sky intensity maps and spectra of interplanetary Lyman-α emission to reveal the global solar wind variability and the nature of the heliosphere and the local interstellar medium.

  15. Use of electrochemical sensors for measurement of air pollution: correcting interference response and validating measurements

    Science.gov (United States)

    Cross, Eben S.; Williams, Leah R.; Lewis, David K.; Magoon, Gregory R.; Onasch, Timothy B.; Kaminsky, Michael L.; Worsnop, Douglas R.; Jayne, John T.

    2017-09-01

    The environments in which we live, work, and play are subject to enormous variability in air pollutant concentrations. To adequately characterize air quality (AQ), measurements must be fast (real time), scalable, and reliable (with known accuracy, precision, and stability over time). Lower-cost air-quality-sensor technologies offer new opportunities for fast and distributed measurements, but a persistent characterization gap remains when it comes to evaluating sensor performance under realistic environmental sampling conditions. This limits our ability to inform the public about pollution sources and inspire policy makers to address environmental justice issues related to air quality. In this paper, initial results obtained with a recently developed lower-cost air-quality-sensor system are reported. In this project, data were acquired with the ARISense integrated sensor package over a 4.5-month time interval during which the sensor system was co-located with a state-operated (Massachusetts, USA) air quality monitoring station equipped with reference instrumentation measuring the same pollutant species. This paper focuses on validating electrochemical (EC) sensor measurements of CO, NO, NO2, and O3 at an urban neighborhood site with pollutant concentration ranges (parts per billion by volume, ppb; 5 min averages, ±1σ): [CO] = 231 ± 116 ppb (spanning 84-1706 ppb), [NO] = 6.1 ± 11.5 ppb (spanning 0-209 ppb), [NO2] = 11.7 ± 8.3 ppb (spanning 0-71 ppb), and [O3] = 23.2 ± 12.5 ppb (spanning 0-99 ppb). Through the use of high-dimensional model representation (HDMR), we show that interference effects derived from the variable ambient gas concentration mix and changing environmental conditions over three seasons (sensor flow-cell temperature = 23.4 ± 8.5 °C, spanning 4.1 to 45.2 °C; and relative humidity = 50.1 ± 15.3 %, spanning 9.8-79.9 %) can be effectively modeled for the Alphasense CO-B4, NO-B4, NO2-B43F, and Ox-B421 sensors, yielding (5 min average) root

  16. Development of sensor-less control strategies for grid connected PMSG based variable speed wind energy conversion system with improved power quality features

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, A. [Quebec Univ., Montreal, PQ (Canada). Dept. of Electrical Engineering

    2010-07-01

    Interest in renewable energy sources has grown in recent years in response to concerns of increasing pollution levels and depleting fossil fuels. Among renewable energy sources, wind energy generation is the fastest growing technology and one of the most cost-effective and environmental friendly means to generate electricity from renewable sources. Modern wind turbines are ready to be deployed in large scale as a result of recent developments in wind power technology. Variable speed permanent magnet synchronous generators (PMSG) based wind energy conversion systems (WECS) are becoming more popular. The use of a permanent magnet reduces size, cost and weight of overall WECS. In addition, the absence of field winding and its excitation system avoids heat dissipation in the rotor winding, thereby improving overall efficiency of the WECS. This type of configuration is more appropriate for remote locations, particularly for off-shore wind application, where the geared doubly fed induction generator usually requires regular maintenance due to tearing-wearing in brushes, windings and gear box. This presentation discussed the development of sensor-less control strategies for grid connected PMSG based variable speed wind energy conversion system with improved power quality features. A novel adaptive network-based fuzzy inference system was used to estimate the speed and position of variable speed PMSG under fluctuating wind conditions. A novel control strategy was developed for the grid interfacing inverter incorporating power quality improvement features at point of common coupling.

  17. Implementation of a Particle Image Velocimetry System for Wind Tunnel Flowfield Measurements

    Science.gov (United States)

    2014-12-01

    Instrumentation Wind tunnel speed was measured by two pitot probes mounted on opposite tunnel walls upstream of the model and above the ground...board. The pitot probes were connected differentially to Scanivalve 1-psi transducers. A secondary measurement of wind tunnel speed was made with the...Manf. Model Range 1 Tunnel Vel (south pitot ) Transducer Scanivalve CR24D 1 psi 2 Tunnel Vel (north pitot ) Transducer Scanivalve CR24D 1 psi 3

  18. Time series analysis of continuous-wave coherent Doppler Lidar wind measurements

    International Nuclear Information System (INIS)

    Sjoeholm, M; Mikkelsen, T; Mann, J; Enevoldsen, K; Courtney, M

    2008-01-01

    The influence of spatial volume averaging of a focused 1.55 μm continuous-wave coherent Doppler Lidar on observed wind turbulence measured in the atmospheric surface layer over homogeneous terrain is described and analysed. Comparison of Lidar-measured turbulent spectra with spectra simultaneously obtained from a mast-mounted sonic anemometer at 78 meters height at the test station for large wind turbines at Hoevsoere in Western Jutland, Denmark is presented for the first time

  19. Unique sensor fusion system for coordinate-measuring machine tasks

    Science.gov (United States)

    Nashman, Marilyn; Yoshimi, Billibon; Hong, Tsai Hong; Rippey, William G.; Herman, Martin

    1997-09-01

    This paper describes a real-time hierarchical system that fuses data from vision and touch sensors to improve the performance of a coordinate measuring machine (CMM) used for dimensional inspection tasks. The system consists of sensory processing, world modeling, and task decomposition modules. It uses the strengths of each sensor -- the precision of the CMM scales and the analog touch probe and the global information provided by the low resolution camera -- to improve the speed and flexibility of the inspection task. In the experiment described, the vision module performs all computations in image coordinate space. The part's boundaries are extracted during an initialization process and then the probe's position is continuously updated as it scans and measures the part surface. The system fuses the estimated probe velocity and distance to the part boundary in image coordinates with the estimated velocity and probe position provided by the CMM controller. The fused information provides feedback to the monitor controller as it guides the touch probe to scan the part. We also discuss integrating information from the vision system and the probe to autonomously collect data for 2-D to 3-D calibration, and work to register computer aided design (CAD) models with images of parts in the workplace.

  20. Hess Tower field study: sonic measurements at a former building-integrated wind farm site

    Science.gov (United States)

    Araya, Daniel

    2017-11-01

    Built in 2010, Hess Tower is a 29-story office building located in the heart of downtown Houston, TX. Unique to the building is a roof structure that was specifically engineered to house ten vertical-axis wind turbines (VAWTs) to partially offset the energy demands of the building. Despite extensive atmospheric boundary layer (ABL) wind tunnel tests to predict the flow conditions on the roof before the building was constructed, the Hess VAWTs were eventually removed after allegedly one of the turbines failed and fell to the ground. This talk presents in-situ sonic anemometry measurements taken on the roof of Hess Tower at the former turbine locations. We compare this wind field characterization to the ABL wind tunnel data to draw conclusions about building-integrated wind farm performance and prediction capability.

  1. Stereo particle image velocimetry set up for measurements in the wake of scaled wind turbines

    Science.gov (United States)

    Campanardi, Gabriele; Grassi, Donato; Zanotti, Alex; Nanos, Emmanouil M.; Campagnolo, Filippo; Croce, Alessandro; Bottasso, Carlo L.

    2017-08-01

    Stereo particle image velocimetry measurements were carried out in the boundary layer test section of Politecnico di Milano large wind tunnel to survey the wake of a scaled wind turbine model designed and developed by Technische Universität München. The stereo PIV instrumentation was set up to survey the three velocity components on cross-flow planes at different longitudinal locations. The area of investigation covered the entire extent of the wind turbines wake that was scanned by the use of two separate traversing systems for both the laser and the cameras. Such instrumentation set up enabled to gain rapidly high quality results suitable to characterise the behaviour of the flow field in the wake of the scaled wind turbine. This would be very useful for the evaluation of the performance of wind farm control methodologies based on wake redirection and for the validation of CFD tools.

  2. Three-dimensional structure of wind turbine wakes as measured by scanning lidar

    Science.gov (United States)

    Bodini, Nicola; Zardi, Dino; Lundquist, Julie K.

    2017-08-01

    The lower wind speeds and increased turbulence that are characteristic of turbine wakes have considerable consequences on large wind farms: turbines located downwind generate less power and experience increased turbulent loads. The structures of wakes and their downwind impacts are sensitive to wind speed and atmospheric variability. Wake characterization can provide important insights for turbine layout optimization in view of decreasing the cost of wind energy. The CWEX-13 field campaign, which took place between June and September 2013 in a wind farm in Iowa, was designed to explore the interaction of multiple wakes in a range of atmospheric stability conditions. Based on lidar wind measurements, we extend, present, and apply a quantitative algorithm to assess wake parameters such as the velocity deficits, the size of the wake boundaries, and the location of the wake centerlines. We focus on wakes from a row of four turbines at the leading edge of the wind farm to explore variations between wakes from the edge of the row (outer wakes) and those from turbines in the center of the row (inner wakes). Using multiple horizontal scans at different elevations, a three-dimensional structure of wakes from the row of turbines can be created. Wakes erode very quickly during unstable conditions and can in fact be detected primarily in stable conditions in the conditions measured here. During stable conditions, important differences emerge between the wakes of inner turbines and the wakes of outer turbines. Further, the strong wind veer associated with stable conditions results in a stretching of the wake structures, and this stretching manifests differently for inner and outer wakes. These insights can be incorporated into low-order wake models for wind farm layout optimization or for wind power forecasting.

  3. All-Fiber Airborne Coherent Doppler Lidar to Measure Wind Profiles

    Directory of Open Access Journals (Sweden)

    Liu Jiqiao

    2016-01-01

    Full Text Available An all-fiber airborne pulsed coherent Doppler lidar (CDL prototype at 1.54μm is developed to measure wind profiles in the lower troposphere layer. The all-fiber single frequency pulsed laser is operated with pulse energy of 300μJ, pulse width of 400ns and pulse repetition rate of 10kHz. To the best of our knowledge, it is the highest pulse energy of all-fiber eye-safe single frequency laser that is used in airborne coherent wind lidar. The telescope optical diameter of monostatic lidar is 100 mm. Velocity-Azimuth-Display (VAD scanning is implemented with 20 degrees elevation angle in 8 different azimuths. Real-time signal processing board is developed to acquire and process the heterodyne mixing signal with 10000 pulses spectra accumulated every second. Wind profiles are obtained every 20 seconds. Several experiments are implemented to evaluate the performance of the lidar. We have carried out airborne wind lidar experiments successfully, and the wind profiles are compared with aerological theodolite and ground based wind lidar. Wind speed standard error of less than 0.4m/s is shown between airborne wind lidar and balloon aerological theodolite.

  4. Design and construction of a simple blade pitch measurement system for small wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Whale, Jonathan [Research Institute of Sustainable Energy, Murdoch University, Perth, WA 6150 (Australia)

    2009-02-15

    For small wind turbines to be reliable they must have in place good mechanisms to protect themselves against very high winds or sudden removal of load. One common protection method in small wind turbines is that of blade feathering. It is important that the blade feathering mechanism of a small wind turbine is tested before the turbine is installed in the field. This paper presents a simple system for monitoring the blade feathering of a turbine with an overall component cost that small wind turbine manufacturers can afford. The Blade Pitch Measurement System (BPMS) has been designed and constructed by the Research Institute of Sustainable Energy (RISE) and aids small wind turbine manufacturers in testing and optimising the settings of the blade feathering mechanisms on their machines. The results show that the BPMS was successful in recording the behaviour of the blade feathering mechanism in field trials with a 20 kW and a 30 kW wind turbine. The BPMS displays significant potential as an effective, inexpensive system for small wind turbine manufacturers to ensure the reliability of their pitch regulating over-speed protection mechanisms. (author)

  5. Fault tolerant control of wind turbines using unknown input observers

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2012-01-01

    This paper presents a scheme for accommodating faults in the rotor and generator speed sensors in a wind turbine. These measured values are important both for the wind turbine controller as well as the supervisory control of the wind turbine. The scheme is based on unknown input observers, which...

  6. Wind field re-construction of 3D Wake measurements from a turbine-installed scanning lidar

    DEFF Research Database (Denmark)

    Mikkelsen, Torben Krogh; Herges, Tommy; Astrup, Poul

    High-resolution wake flow measurements obtained from a turbine-mounted scanning lidar have been obtained from 1D to 5D behind a V27 test turbine. The measured line-of-sight projected wind speeds have, in connection with a fast CFD wind field reconstruction model, been used to generate 3D wind fie...

  7. Janus: Graphical Software for Analyzing In-Situ Measurements of Solar-Wind Ions

    Science.gov (United States)

    Maruca, B.; Stevens, M. L.; Kasper, J. C.; Korreck, K. E.

    2016-12-01

    In-situ observations of solar-wind ions provide tremendous insights into the physics of space plasmas. Instrument on spacecraft measure distributions of ion energies, which can be processed into scientifically useful data (e.g., values for ion densities and temperatures). This analysis requires a strong, technical understanding of the instrument, so it has traditionally been carried out by the instrument teams using automated software that they had developed for that purpose. The automated routines are optimized for typical solar-wind conditions, so they can fail to capture the complex (and scientifically interesting) microphysics of transient solar-wind - such as coronal mass ejections (CME's) and co-rotating interaction regions (CIR's) - which are often better analyzed manually.This presentation reports on the ongoing development of Janus, a new software package for processing in-situ measurement of solar-wind ions. Janus will provide user with an easy-to-use graphical user interface (GUI) for carrying out highly customized analyses. Transparent to the user, Janus will automatically handle the most technical tasks (e.g., the retrieval and calibration of measurements). For the first time, users with only limited knowledge about the instruments (e.g., non-instrumentalists and students) will be able to easily process measurements of solar-wind ions. Version 1 of Janus focuses specifically on such measurements from the Wind spacecraft's Faraday Cups and is slated for public release in time for this presentation.

  8. Measurement of drill grinding parameters using laser sensor

    Science.gov (United States)

    Yanping, Peng; Kumehara, Hiroyuki; Wei, Zhang; Nomura, Takashi

    2005-12-01

    To measure the grinding parameters and geometry parameters accurately for a drill point is essential to its design and reconditioning. In recent years, a number of non-contact coordinate measuring apparatuses, using CCD camera or laser sensors, are developed. But, a lot work is to be done for further improvement. This paper reports another kind of laser coordinate meter. As an example of its application, the method for geometry inspection of the drill flank surface is detailed. Measured data from laser scanning on the flank surface around some points with several 2-dimensional curves are analyzed with mathematical procedure. If one of these curves turns to be a straight line, it must be the generatrix of the grinding cone. Thus, the grinding parameters are determined by a set of three generatrices. Then, the measurement method and data processing procedure are proposed. Its validity is assessed by measuring a sample with given parameters. The point geometry measured agrees well with the known values. In comparison with other methods in the published literature, it is simpler in computation and more accurate in results.

  9. Chemical, Biological, and Explosive Sensors for Field Measurements

    International Nuclear Information System (INIS)

    Kyle, Kevin; Manard, Manuel; Weeks, Stephan

    2009-01-01

    Special Technologies Laboratory (STL) is developing handheld chemical, biological, and explosive (CBE) detection systems and sensor motes for wireless networked field operations. The CBE sensors are capable of detecting and identifying multiple targeted toxic industrial chemicals (TICs) and high-explosive vapor components. The CBE devices are based on differential mobility spectrometry (DMS) coupled with fast gas chromatography (GC) or mass spectrometry. The systems all include the concepts of: (1) Direct air/particulate 'smart' sampling; (2) Selective, continuous real-time (∼1 sec) alert monitoring using DMS; and (3) Highly selective, rapid dual technology separation/verification analysis The biosensor technology is based on Raman aerosol particle flow cytometry for target detection and identification. Monitoring and identifying trace level chemical vapors directly from ambient air will allow First Responders to quickly adapt situational response strategies and personal protective equipment needs to the specific response scenario being encountered. First Responders require great confidence in the measurements and ability of a given system to detect CBE below threshold levels without interferences. The concept of determining the background matrix in near real-time to allow subsequent automated field-programmable method selection and cueing of high-value assets in a wide range of environs will be presented. This provides CBE information for decisions prior to First Responders entering the response site or sending a portable mobile unit for a remote site survey of the hazards. The focus is on real-time information needed by those responsible for emergency response and national security

  10. Saharan dust detection using multi-sensor satellite measurements

    Directory of Open Access Journals (Sweden)

    Sriharsha Madhavan

    2017-02-01

    Full Text Available Contemporary scientists have vested interest in trying to understand the climatology of the North Atlantic Basin since this region is considered as the genesis for hurricane formation that eventually get shipped to the tropical Atlantic region and the Caribbean. The effects of atmospheric water cycle and the climate of West Africa and the Atlantic basin are hugely impacted by the radiative forcing of Saharan dust. The focus area in this paper would be to improve the dust detection schemes by employing the use of multi sensor measurements in the thermal emissive wavelengths using legacy sensors such as Terra (T and Aqua (A MODerate-resolution Imaging Spectroradiometer (MODIS, fusing with Ozone Monitoring Instrument (OMI. Previous work by Hao and Qu (2007 had considered a limited number of thermal infrared channels which led to a correlation coefficient R2 value of 0.765 between the Aerosol Optical Thickness (AOT at 550 nm and the modeled dust index. In this work, we extend the thermal infrared based dust detection by employing additional channels: the 8.55 μm which has shown high sensitivity to the Saharan dust, along with water vapor channel of 7.1 μm and cloud top channel of 13.1 μm. Also, the dust pixels were clearly identified using the OMI based aerosol types. The dust pixels were cleanly segregated from the other aerosol types such as sulfates, biomass, and other carbonaceous aerosols. These improvements led to a much higher correlation coefficient R2 value of 0.85 between the modified dust index and the AOT in comparison to the previous work. The key limitations from the current AOT products based on MODIS and were put to test by validating the improved dust detection algorithm. Two improvements were noted. First, the dust measurement radiometry using MODIS is significantly improved by at least an order of 2. Second the spatial measurements are enhanced by a factor of at least 10.

  11. Integrated CMOS dew point sensors for relative humidity measurement

    Science.gov (United States)

    Savalli, Nicolo; Baglio, Salvatore; Castorina, Salvatore; Sacco, Vincenzo; Tringali, Cristina

    2004-07-01

    This work deals with the development of integrated relative humidity dew point sensors realized by adopting standard CMOS technology for applications in various fields. The proposed system is composed by a suspended plate that is cooled by exploiting integrated Peltier cells. The cold junctions of the cells have been spread over the plate surface to improve the homogeneity of the temperature distribution over its surface, where cooling will cause the water condensation. The temperature at which water drops occur, named dew point temperature, is a function of the air humidity. Measurement of such dew point temperature and the ambient temperature allows to know the relative humidity. The detection of water drops is achieved by adopting a capacitive sensing strategy realized by interdigited fixed combs, composed by the upper layer of the adopted process. Such a capacitive sensor, together with its conditioning circuit, drives a trigger that stops the cooling of the plate and enables the reading of the dew point temperature. Temperature measurements are achieved by means of suitably integrated thermocouples. The analytical model of the proposed system has been developed and has been used to design a prototype device and to estimate its performances. In such a prototype, the thermoelectric cooler is composed by 56 Peltier cells, made by metal 1/poly 1 junctions. The plate has a square shape with 200 μm side, and it is realized by exploiting the oxide layers. Starting from the ambient temperature a temperature variation of ΔT = 15 K can be reached in 10 ms thus allowing to measure a relative humidity greater than 40%.

  12. Assessing Long-Term Wind Conditions by Combining Different Measure-Correlate-Predict Algorithms: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J.; Chowdhury, S.; Messac, A.; Hodge, B. M.

    2013-08-01

    This paper significantly advances the hybrid measure-correlate-predict (MCP) methodology, enabling it to account for variations of both wind speed and direction. The advanced hybrid MCP method uses the recorded data of multiple reference stations to estimate the long-term wind condition at a target wind plant site. The results show that the accuracy of the hybrid MCP method is highly sensitive to the combination of the individual MCP algorithms and reference stations. It was also found that the best combination of MCP algorithms varies based on the length of the correlation period.

  13. Understanding and Exploiting Wind Tunnels with Porous Flexible Walls for Aerodynamic Measurement

    OpenAIRE

    Brown, Kenneth Alexander

    2016-01-01

    The aerodynamic behavior of wind tunnels with porous, flexible walls formed from tensioned Kevlar has been characterized and new measurement techniques in such wind tunnels explored. The objective is to bring the aerodynamic capabilities of so-called Kevlar-wall test sections in-line with those of traditional solid-wall test sections. The primary facility used for this purpose is the 1.85-m by 1.85-m Stability Wind Tunnel at Virginia Tech, and supporting data is provided by the 2-m by 2-m L...

  14. A miniature integrated multimodal sensor for measuring pH, EC and temperature for precision agriculture.

    Science.gov (United States)

    Futagawa, Masato; Iwasaki, Taichi; Murata, Hiroaki; Ishida, Makoto; Sawada, Kazuaki

    2012-01-01

    Making several simultaneous measurements with different kinds of sensors at the same location in a solution is difficult because of crosstalk between the sensors. In addition, because the conditions at different locations in plant beds differ, in situ measurements in agriculture need to be done in small localized areas. We have fabricated a multimodal sensor on a small Si chip in which a pH sensor was integrated with electrical conductivity (EC) and temperature sensors. An ISFET with a Si(3)N(4) membrane was used for the pH sensor. For the EC sensor, the electrical conductivity between platinum electrodes was measured, and the temperature sensor was a p-n junction diode. These are some of the most important measurements required for controlling the conditions in plant beds. The multimodal sensor can be inserted into a plant bed for in situ monitoring. To confirm the absence of crosstalk between the sensors, we made simultaneous measurements of pH, EC, and temperature of a pH buffer solution in a plant bed. When the solution was diluted with hot or cold water, the real time measurements showed changes to the EC and temperature, but no change in pH. We also demonstrated that our sensor was capable of simultaneous in situ measurements in rock wool without being affected by crosstalk.

  15. A Miniature Integrated Multimodal Sensor for Measuring pH, EC and Temperature for Precision Agriculture

    Directory of Open Access Journals (Sweden)

    Hiroaki Murata

    2012-06-01

    Full Text Available Making several simultaneous measurements with different kinds of sensors at the same location in a solution is difficult because of crosstalk between the sensors. In addition, because the conditions at different locations in plant beds differ, in situ measurements in agriculture need to be done in small localized areas. We have fabricated a multimodal sensor on a small Si chip in which a pH sensor was integrated with electrical conductivity (EC and temperature sensors. An ISFET with a Si3N4 membrane was used for the pH sensor. For the EC sensor, the electrical conductivity between platinum electrodes was measured, and the temperature sensor was a p-n junction diode. These are some of the most important measurements required for controlling the conditions in plant beds. The multimodal sensor can be inserted into a plant bed for in situ monitoring. To confirm the absence of crosstalk between the sensors, we made simultaneous measurements of pH, EC, and temperature of a pH buffer solution in a plant bed. When the solution was diluted with hot or cold water, the real time measurements showed changes to the EC and temperature, but no change in pH. We also demonstrated that our sensor was capable of simultaneous in situ measurements in rock wool without being affected by crosstalk.

  16. A Wireless Sensor Network for the Real-Time Remote Measurement of Aeolian Sand Transport on Sandy Beaches and Dunes.

    Science.gov (United States)

    Pozzebon, Alessandro; Cappelli, Irene; Mecocci, Alessandro; Bertoni, Duccio; Sarti, Giovanni; Alquini, Fernanda

    2018-03-08

    Direct measurements of aeolian sand transport on coastal dunes and beaches is of paramount importance to make correct decisions about coast management. As most of the existing studies are mainly based on a statistical approach, the solution presented in this paper proposes a sensing structure able to orient itself according to wind direction and directly calculate the amount of wind-transported sand by collecting it and by measuring its weight. Measurements are performed remotely without requiring human action because the structure is equipped with a ZigBee radio module, which periodically sends readings to a local gateway. Here data are processed by a microcontroller and then transferred to a remote data collection centre, through GSM technology. The ease of installation, the reduced power consumption and the low maintenance required, make the proposed solution able to work independently, limiting human intervention, for all the duration of the expected experimental campaign. In order to analyze the cause-effect relationship between the transported sand and the wind, the sensing structure is integrated with a multi-layer anemoscope-anemometer structure. The overall sensor network has been developed and tested in the laboratory, and its operation has been validated in field through a 48 h measurement campaign.

  17. A Wireless Sensor Network for the Real-Time Remote Measurement of Aeolian Sand Transport on Sandy Beaches and Dunes

    Science.gov (United States)

    Cappelli, Irene; Mecocci, Alessandro; Alquini, Fernanda

    2018-01-01

    Direct measurements of aeolian sand transport on coastal dunes and beaches is of paramount importance to make correct decisions about coast management. As most of the existing studies are mainly based on a statistical approach, the solution presented in this paper proposes a sensing structure able to orient itself according to wind direction and directly calculate the amount of wind-transported sand by collecting it and by measuring its weight. Measurements are performed remotely without requiring human action because the structure is equipped with a ZigBee radio module, which periodically sends readings to a local gateway. Here data are processed by a microcontroller and then transferred to a remote data collection centre, through GSM technology. The ease of installation, the reduced power consumption and the low maintenance required, make the proposed solution able to work independently, limiting human intervention, for all the duration of the expected experimental campaign. In order to analyze the cause-effect relationship between the transported sand and the wind, the sensing structure is integrated with a multi-layer anemoscope-anemometer structure. The overall sensor network has been developed and tested in the laboratory, and its operation has been validated in field through a 48 h measurement campaign. PMID:29518060

  18. A combined aeroelastic-aeroacoustic model for wind turbine noise: Verification and analysis of field measurements

    DEFF Research Database (Denmark)

    Bertagnolio, Franck; Aagaard Madsen, Helge; Fischer, Andreas

    2017-01-01

    In this paper, semi-empirical engineering models for the three main wind turbine aerodynamic noise sources, namely, turbulent inflow, trailing edge and stall noise, are introduced. They are implemented into the in-house aeroelastic code HAWC2 commonly used for wind turbine load calculations...... and design. The results of the combined aeroelastic and aeroacoustic model are compared with field noise measurements of a 500kW wind turbine. Model and experimental data are in fairly good agreement in terms of noise levels and directivity. The combined model allows separating the various noise sources...... and highlights a number of mechanisms that are difficult to differentiate when only the overall noise from a wind turbine is measured....

  19. Optimization of Wind Turbine Operation by Use of Spinner Anemometer

    DEFF Research Database (Denmark)

    Friis Pedersen, Troels; Sørensen, Niels N.; Vita, Luca

    A prototype spinner anemometer was developed from a standard scientific sonic anemometer with specially designed 1D sonic sensors. A model spinner anemometer was tested in wind tunnel with two sensor head configurations. The tests showed that the sonic sensors responded with a high influence factor...... correlated with wind speed and wind direction from a free meteorology mast. The results showed that the gain factor of the yaw error was only 0.80, which indicates that the yaw error measurements were overestimated with the use of the K factors from the CFD analysis. The wind speed at the free mast ahead...

  20. A comparison of measured wind park load histories with the WISPER and WISPERX load spectra

    Science.gov (United States)

    Kelley, N. D.

    1995-01-01

    The blade-loading histories from two adjacent Micon 65/13 wind turbines are compared with the variable-amplitude test-loading histories known as the WISPER and WISPERX spectra. These standardized loading sequences were developed from blade flapwise load histories taken from nine different horizontal-axis wind turbines operating under a wide range of conditions in Europe. The subject turbines covered a broad spectrum of rotor diameters, materials, and operating environments. The final loading sequences were developed as a joint effort of thirteen different European organizations. The goal was to develop a meaningful loading standard for horizontal-axis wind turbine blades that represents common interaction effects seen in service. In 1990, NREL made extensive load measurements on two adjacent Micon 65/13 wind turbines in simultaneous operation in the very turbulent environment of a large wind park. Further, before and during the collection of the loads data, comprehensive measurements of the statistics of the turbulent environment were obtained at both the turbines under test and at two other locations within the park. The trend to larger but lighter wind turbine structures has made an understanding of the expected lifetime loading history of paramount importance. Experience in the US has shown that the turbulence-induced loads associated with multi-row wind parks in general are much more severe than for turbines operating individually or within widely spaced environments. Multi-row wind parks are much more common in the US than in Europe. In this paper we report on our results in applying the methodology utilized to develop the WISPER and WISPERX standardized loading sequences using the available data from the Micon turbines. While the intended purpose of the WISPER sequences were not to represent a specific operating environment, we believe the exercise is useful, especially when a turbine design is likely to be installed in a multi-row wind park.

  1. Measuring electromagnetic fields (EMF) around wind turbines in Canada: is there a human health concern?

    OpenAIRE

    McCallum, Lindsay C; Whitfield Aslund, Melissa L; Knopper, Loren D; Ferguson, Glenn M; Ollson, Christopher A

    2014-01-01

    Background The past five years has seen considerable expansion of wind power generation in Ontario, Canada. Most recently worries about exposure to electromagnetic fields (EMF) from wind turbines, and associated electrical transmission, has been raised at public meetings and legal proceedings. These fears have not been based on any actual measurements of EMF exposure surrounding existing projects but appear to follow from worries from internet sources and misunderstanding of the science. Meth...

  2. Maximum power point tracking-based control algorithm for PMSG wind generation system without mechanical sensors

    International Nuclear Information System (INIS)

    Hong, Chih-Ming; Chen, Chiung-Hsing; Tu, Chia-Sheng

    2013-01-01

    Highlights: ► This paper presents MPPT based control for optimal wind energy capture using RBFN. ► MPSO is adopted to adjust the learning rates to improve the learning capability. ► This technique can maintain the system stability and reach the desired performance. ► The EMF in the rotating reference frame is utilized in order to estimate speed. - Abstract: This paper presents maximum-power-point-tracking (MPPT) based control algorithms for optimal wind energy capture using radial basis function network (RBFN) and a proposed torque observer MPPT algorithm. The design of a high-performance on-line training RBFN using back-propagation learning algorithm with modified particle swarm optimization (MPSO) regulating controller for the sensorless control of a permanent magnet synchronous generator (PMSG). The MPSO is adopted in this study to adapt the learning rates in the back-propagation process of the RBFN to improve the learning capability. The PMSG is controlled by the loss-minimization control with MPPT below the base speed, which corresponds to low and high wind speed, and the maximum energy can be captured from the wind. Then the observed disturbance torque is feed-forward to increase the robustness of the PMSG system

  3. Time series analysis of continuous-wave coherent Doppler Lidar wind measurements

    DEFF Research Database (Denmark)

    Sjöholm, Mikael; Mikkelsen, Torben; Mann, Jakob

    2008-01-01

    The influence of spatial volume averaging of a focused 1.55 mu m continuous-wave coherent Doppler Lidar on observed wind turbulence measured in the atmospheric surface layer over homogeneous terrain is described and analysed. Comparison of Lidar-measured turbulent spectra with spectra simultaneou......The influence of spatial volume averaging of a focused 1.55 mu m continuous-wave coherent Doppler Lidar on observed wind turbulence measured in the atmospheric surface layer over homogeneous terrain is described and analysed. Comparison of Lidar-measured turbulent spectra with spectra...

  4. Measurement of agricultural parameters using wireless sensor network (WSN)

    Science.gov (United States)

    Guaña-Moya, Javier; Sánchez-Almeida, Tarquino; Salgado-Reyes, Nelson

    2018-04-01

    The technological advances have allowed to create new applications in telecommunications, applying low power and reduced costs in their equipment, thus achieving the evolution of new wireless networks or also denominated Wireless Sensor Network. These technologies allow the generation of measurements and analysis of environmental parameter data and soil. Precision agriculture requires parameters for the improvement of production, obtained through WSN technologies. This research analyzes the climatic requirements and soil parameters in a rose plantation in a greenhouse at an altitude of 3,100 meters above sea level. In the present investigation, maximum parameters were obtained in the production of roses, which are in the optimum range of production, whereas the minimum parameters of temperature, humidity and luminosity, evidenced that these parameters can damage the plants, since temperatures less than 10 °C slow down the growth of the plant and allow the proliferation of diseases and fungi.

  5. Measuring electromagnetic fields (EMF) around wind turbines in Canada: is there a human health concern?

    Science.gov (United States)

    McCallum, Lindsay C; Whitfield Aslund, Melissa L; Knopper, Loren D; Ferguson, Glenn M; Ollson, Christopher A

    2014-02-15

    The past five years has seen considerable expansion of wind power generation in Ontario, Canada. Most recently worries about exposure to electromagnetic fields (EMF) from wind turbines, and associated electrical transmission, has been raised at public meetings and legal proceedings. These fears have not been based on any actual measurements of EMF exposure surrounding existing projects but appear to follow from worries from internet sources and misunderstanding of the science. The study was carried out at the Kingsbridge 1 Wind Farm located near Goderich, Ontario, Canada. Magnetic field measurements were collected in the proximity of 15 Vestas 1.8 MW wind turbines, two substations, various buried and overhead collector and transmission lines, and nearby homes. Data were collected during three operational scenarios to characterize potential EMF exposure: 'high wind' (generating power), 'low wind' (drawing power from the grid, but not generating power) and 'shut off' (neither drawing, nor generating power). Background levels of EMF (0.2 to 0.3 mG) were established by measuring magnetic fields around the wind turbines under the 'shut off' scenario. Magnetic field levels detected at the base of the turbines under both the 'high wind' and 'low wind' conditions were low (mean = 0.9 mG; n = 11) and rapidly diminished with distance, becoming indistinguishable from background within 2 m of the base. Magnetic fields measured 1 m above buried collector lines were also within background (≤ 0.3 mG). Beneath overhead 27.5 kV and 500 kV transmission lines, magnetic field levels of up to 16.5 and 46 mG, respectively, were recorded. These levels also diminished rapidly with distance. None of these sources appeared to influence magnetic field levels at nearby homes located as close as just over 500 m from turbines, where measurements immediately outside of the homes were ≤ 0.4 mG. The results suggest that there is nothing unique to wind farms with respect to EMF exposure; in

  6. Full two-dimensional rotor plane inflow measurements by a spinner-integrated wind lidar

    DEFF Research Database (Denmark)

    Sjöholm, Mikael; Pedersen, Anders Tegtmeier; Angelou, Nikolas

    2013-01-01

    Introduction Wind turbine load reduction and power performance optimization via advanced control strategies is an active area in the wind energy community. In particular, feed-forward control using upwind inflow measurements by lidar (light detection and ranging) remote sensing instruments has...... novel full two-dimensional radial inflow measurements. Approach In order to achieve full two-dimensional radial inflow measurements, a special laser beam scanner has been developed at the DTU Wind Energy Department. It is based on two rotating prisms that each deviate the beam by 15°, resulting......, a proof-of-concept trial with a blade mounted lidar was performed during the measurement campaign and is reported in a separate EWEA 2013 contribution. Conclusion The study presented here is the novel full two-dimensional continuation of the previous inflow measurements on a circle presented in the paper...

  7. Noninvasive Sensor for Measuring Muscle Metabolism During Exercise

    Science.gov (United States)

    Soller, B. R.; Yang, Y.; Lee, S. M. C.; Soyemi, O. O.; Wilson, C.; Hagan, R. D.

    2007-01-01

    The measurement of oxygen uptake (VO2) and lactate threshold (LT) are utilized to assess changes in aerobic capacity and the efficacy of exercise countermeasures in astronauts. During extravehicular activity (EVA), real-time knowledge of VO2 and relative work intensity can be used to monitor crew activity levels and organize tasks to reduce the cumulative effects of fatigue. Currently VO2 and LT are determined with complicated measurement techniques that require sampling of expired ventilatory gases, which may not be accurate in enclosed, oxygen-rich environments such as the EVA suit. The UMMS team has developed a novel near infrared spectroscopic (NIRS) system which noninvasively, simultaneously and continuously measures muscle oxygen tension, oxygen saturation, pH (pHm), and hematocrit from a small sensor placed on the leg. This system is unique in that it allows accurate, absolute measurement of these parameters in the thigh muscle by correcting spectra for the interference from skin pigment and fat. These parameters can be used to estimate VO2 and LT. A preliminary evaluation of the system s capabilities was performed in the NASA JSC Exercise Physiology Lab.

  8. Measurement strategy for rectangular electrical capacitance tomography sensor

    International Nuclear Information System (INIS)

    Ye, Jiamin; Ge, Ruihuan; Qiu, Guizhi; Wang, Haigang

    2014-01-01

    To investigate the influence of the measurement strategy for the rectangular electrical capacitance tomography (ECT) sensor, a Finite Element Method (FEM) is utilized to create the model for simulation. The simulation was carried out using COMSOL Multiphysics(trade mark, serif) and Matlab(trade mark, serif). The length-width ratio of the rectangular sensing area is 5. Twelve electrodes are evenly arranged surrounding the pipe. The covering ratio of the electrodes is 90%. The capacitances between different electrode pairs are calculated for a bar distribution. The air of the relative permittivity 1.0 and the material of the permittivity 3.0 are used for the calibration. The relative permittivity of the second phase is 3.0. The noise free and noise data are used for the image reconstruction using the Linear Back Projection (LBP). The measurement strategies with 1-, 2- and 4- electrode excitation are compared using the correlation coefficient. Preliminary results show that the measurement strategy with 2-electrode excitation outperforms other measurement strategies with 1- or 4-electrode excitation

  9. Real-Time Alpine Measurement System Using Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Sami A. Malek

    2017-11-01

    Full Text Available Monitoring the snow pack is crucial for many stakeholders, whether for hydro-power optimization, water management or flood control. Traditional forecasting relies on regression methods, which often results in snow melt runoff predictions of low accuracy in non-average years. Existing ground-based real-time measurement systems do not cover enough physiographic variability and are mostly installed at low elevations. We present the hardware and software design of a state-of-the-art distributed Wireless Sensor Network (WSN-based autonomous measurement system with real-time remote data transmission that gathers data of snow depth, air temperature, air relative humidity, soil moisture, soil temperature, and solar radiation in physiographically representative locations. Elevation, aspect, slope and vegetation are used to select network locations, and distribute sensors throughout a given network location, since they govern snow pack variability at various scales. Three WSNs were installed in the Sierra Nevada of Northern California throughout the North Fork of the Feather River, upstream of the Oroville dam and multiple powerhouses along the river. The WSNs gathered hydrologic variables and network health statistics throughout the 2017 water year, one of northern Sierra’s wettest years on record. These networks leverage an ultra-low-power wireless technology to interconnect their components and offer recovery features, resilience to data loss due to weather and wildlife disturbances and real-time topological visualizations of the network health. Data show considerable spatial variability of snow depth, even within a 1 km 2 network location. Combined with existing systems, these WSNs can better detect precipitation timing and phase in, monitor sub-daily dynamics of infiltration and surface runoff during precipitation or snow melt, and inform hydro power managers about actual ablation and end-of-season date across the landscape.

  10. Real-Time Alpine Measurement System Using Wireless Sensor Networks.

    Science.gov (United States)

    Malek, Sami A; Avanzi, Francesco; Brun-Laguna, Keoma; Maurer, Tessa; Oroza, Carlos A; Hartsough, Peter C; Watteyne, Thomas; Glaser, Steven D

    2017-11-09

    Monitoring the snow pack is crucial for many stakeholders, whether for hydro-power optimization, water management or flood control. Traditional forecasting relies on regression methods, which often results in snow melt runoff predictions of low accuracy in non-average years. Existing ground-based real-time measurement systems do not cover enough physiographic variability and are mostly installed at low elevations. We present the hardware and software design of a state-of-the-art distributed Wireless Sensor Network (WSN)-based autonomous measurement system with real-time remote data transmission that gathers data of snow depth, air temperature, air relative humidity, soil moisture, soil temperature, and solar radiation in physiographically representative locations. Elevation, aspect, slope and vegetation are used to select network locations, and distribute sensors throughout a given network location, since they govern snow pack variability at various scales. Three WSNs were installed in the Sierra Nevada of Northern California throughout the North Fork of the Feather River, upstream of the Oroville dam and multiple powerhouses along the river. The WSNs gathered hydrologic variables and network health statistics throughout the 2017 water year, one of northern Sierra's wettest years on record. These networks leverage an ultra-low-power wireless technology to interconnect their components and offer recovery features, resilience to data loss due to weather and wildlife disturbances and real-time topological visualizations of the network health. Data show considerable spatial variability of snow depth, even within a 1 km 2 network location. Combined with existing systems, these WSNs can better detect precipitation timing and phase in, monitor sub-daily dynamics of infiltration and surface runoff during precipitation or snow melt, and inform hydro power managers about actual ablation and end-of-season date across the landscape.

  11. On-line plutonium measurement by alpha counting using a silica glass sensor

    International Nuclear Information System (INIS)

    Edeline, J.C.; Furgolle, B.

    1980-01-01

    Some cerium activated high purity silica glasses are good sensors for ionising particles counting. These sensors may be used for measuring plutonium concentrations in corrosive solutions which are typical in reprocessing operations. The thickness of the sensor has been reduced to minimize beta sensitivity. The thin sensor is hold by molecular adhesion to a thick glass mount which is soldered to the stainless steel sample cell [fr

  12. LIDAR Wind Speed Measurement Analysis and Feed-Forward Blade Pitch Control for Load Mitigation in Wind Turbines: January 2010--January 2011

    Energy Technology Data Exchange (ETDEWEB)

    Dunne, F.; Simley, E.; Pao, L.Y.

    2011-10-01

    This report examines the accuracy of measurements that rely on Doppler LIDAR systems to determine their applicability to wind turbine feed-forward control systems and discusses feed-forward control system designs that use preview wind measurements. Light Detection and Ranging (LIDAR) systems are able to measure the speed of incoming wind before it interacts with a wind turbine rotor. These preview wind measurements can be used in feed-forward control systems designed to reduce turbine loads. However, the degree to which such preview-based control techniques can reduce loads by reacting to turbulence depends on how accurately the incoming wind field can be measured. The first half of this report examines the accuracy of different measurement scenarios that rely on coherent continuous-wave or pulsed Doppler LIDAR systems to determine their applicability to feed-forward control. In particular, the impacts of measurement range and angular offset from the wind direction are studied for various wind conditions. A realistic case involving a scanning LIDAR unit mounted in the spinner of a wind turbine is studied in depth with emphasis on choices for scan radius and preview distance. The effects of turbulence parameters on measurement accuracy are studied as well. Continuous-wave and pulsed LIDAR models based on typical commercially available units were used in the studies present in this report. The second half of this report discusses feed-forward control system designs that use preview wind measurements. Combined feedback/feed-forward blade pitch control is compared to industry standard feedback control when simulated in realistic turbulent above-rated winds. The feed-forward controllers are designed to reduce fatigue loads, increasing turbine lifetime and therefore reducing the cost of energy. Three feed-forward designs are studied: non-causal series expansion, Preview Control, and optimized FIR filter. The input to the feed-forward controller is a measurement of

  13. Active and Passive Hybrid Sensor

    Science.gov (United States)

    Carswell, James R.

    2010-01-01

    A hybrid ocean wind sensor (HOWS) can map ocean vector wind in low to hurricane-level winds, and non-precipitating and precipitating conditions. It can acquire active and passive measurements through a single aperture at two wavelengths, two polarizations, and multiple incidence angles. Its low profile, compact geometry, and low power consumption permits installation on air craft platforms, including high-altitude unmanned aerial vehicles (UAVs).

  14. A family of fiber-optic based pressure sensors for intracochlear measurements

    Science.gov (United States)

    Olson, Elizabeth S.; Nakajima, Hideko H.

    2015-02-01

    Fiber-optic pressure sensors have been developed for measurements of intracochlear pressure. The present family of transducers includes an 81 μm diameter sensor employing a SLED light source and single-mode optic fiber, and LED/multi-mode sensors with 126 and 202 μm diameter. The 126 μm diameter pressure sensor also has been constructed with an electrode adhered to its side, for coincident pressure and voltage measurements. These sensors have been used for quantifying cochlear mechanical impedances, informing our understanding of conductive hearing loss and its remediation, and probing the operation of the cochlear amplifier.

  15. Influence of different land surfaces on atmospheric conditions measured by a wireless sensor network

    Science.gov (United States)

    Lengfeld, Katharina; Ament, Felix

    2010-05-01

    Atmospheric conditions close to the surface, like temperature, wind speed and humidity, vary on small scales because of surface heterogeneities. Therefore, the traditional measuring approach of using a single, highly accurate station is of limited representativeness for a larger domain, because it is not able to determine these small scale variabilities. However, both the variability and the domain averages are important information for the development and validation of atmospheric models and soil-vegetation-atmosphere-transfer (SVAT) schemes. Due to progress in microelectronics it is possible to construct networks of comparably cheap meteorological stations with moderate accuracy. Such a network provides data in high spatial and temporal resolution. The EPFL Lausanne developed such a network called SensorScope, consisting of low cost autonomous stations. Each station observes air and surface temperature, humidity, wind direction and speed, incoming solar radiation, precipitations, soil moisture and soil temperature and sends the data via radio communication to a base station. This base station forwards the collected data via GSM/GPRS to a central server. Within the FLUXPAT project in August 2009 we deployed 15 stations as a twin transect near Jülich, Germany. One aim of this first experiment was to test the quality of the low cost sensors by comparing them to more accurate reference measurements. It turned out, that although the network is not highly accurate, the measurements are consistent. Consequently an analysis of the pattern of atmospheric conditions is feasible. For example, we detect a variability of ± 0.5K in the mean temperature at a distance of only 2.3 km. The transect covers different types of vegetation and a small river. Therefore, we analyzed the influence of different land surfaces and the distance to the river on meteorological conditions. On the one hand, some results meet our expectations, e.g. the relative humidity decreases with increasing

  16. Two phase flow measurement and visualization using Wire Mesh Sensors (WMS)

    International Nuclear Information System (INIS)

    Rajalakshmi, R.; Robin, Roshini; Rama Rao, A.

    2016-01-01

    Two phase flow behavior studies have gained importance in nuclear power plants to enhance fuel performance and safety. In this paper, taking into consideration low cost, high space-time resolution and instantaneous mapping, electrical sensors such as wire mesh sensors (WMS) is proposed for measurement of void distribution and its visualization. The sensor works on the conductivity principle and by measuring the variations in conductivity values of the two phases, the flow distributions can be identified. This paper describes the conceptual design of the WMS for two phase void measurements, Mathematical modeling of the sensor for data evaluation, modeling of the sensor geometry and FEM simulation studies for optimizing sensor geometry and excitation parameters, CFD two phase flows simulations, development of suitable algorithm and programming for two phase visualization and void distribution studies, prototype sensor fabrication and testing

  17. Autonomous Quality Control of Joint Orientation Measured with Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Karina Lebel

    2016-07-01

    Full Text Available Clinical mobility assessment is traditionally performed in laboratories using complex and expensive equipment. The low accessibility to such equipment, combined with the emerging trend to assess mobility in a free-living environment, creates a need for body-worn sensors (e.g., inertial measurement units—IMUs that are capable of measuring the complexity in motor performance using meaningful measurements, such as joint orientation. However, accuracy of joint orientation estimates using IMUs may be affected by environment, the joint tracked, type of motion performed and velocity. This study investigates a quality control (QC process to assess the quality of orientation data based on features extracted from the raw inertial sensors’ signals. Joint orientation (trunk, hip, knee, ankle of twenty participants was acquired by an optical motion capture system and IMUs during a variety of tasks (sit, sit-to-stand transition, walking, turning performed under varying conditions (speed, environment. An artificial neural network was used to classify good and bad sequences of joint orientation with a sensitivity and a specificity above 83%. This study confirms the possibility to perform QC on IMU joint orientation data based on raw signal features. This innovative QC approach may be of particular interest in a big data context, such as for remote-monitoring of patients’ mobility.

  18. Advanced interfacing techniques for sensors measurement circuits and systems for intelligent sensors

    CERN Document Server

    Roy, Joyanta; Kumar, V; Mukhopadhyay, Subhas

    2017-01-01

    This book presents ways of interfacing sensors to the digital world, and discusses the marriage between sensor systems and the IoT: the opportunities and challenges. As sensor output is often affected by noise and interference, the book presents effective schemes for recovering the data from a signal that is buried in noise. It also explores interesting applications in the area of health care, un-obstructive monitoring and the electronic nose and tongue. It is a valuable resource for engineers and scientists in the area of sensors and interfacing wanting to update their knowledge of the latest developments in the field and learn more about sensing applications and challenges.

  19. Using High-Fidelity Computational Fluid Dynamics to Help Design a Wind Turbine Wake Measurement Experiment

    International Nuclear Information System (INIS)

    Churchfield, M; Wang, Q; Scholbrock, A; Herges, T; Mikkelsen, T; Sjöholm, M

    2016-01-01

    We describe the process of using large-eddy simulations of wind turbine wake flow to help design a wake measurement campaign. The main goal of the experiment is to measure wakes and wake deflection that result from intentional yaw misalignment under a variety of atmospheric conditions at the Scaled Wind Farm Technology facility operated by Sandia National Laboratories in Lubbock, Texas. Prior simulation studies have shown that wake deflection may be used for wind-plant control that maximizes plant power output. In this study, simulations are performed to characterize wake deflection and general behavior before the experiment is performed to ensure better upfront planning. Beyond characterizing the expected wake behavior, we also use the large-eddy simulation to test a virtual version of the lidar we plan to use to measure the wake and better understand our lidar scan strategy options. This work is an excellent example of a “simulation-in-the-loop” measurement campaign. (paper)

  20. Simulated wind-generated inertial oscillations compared to current measurements in the northern North Sea

    Science.gov (United States)

    Bruserud, Kjersti; Haver, Sverre; Myrhaug, Dag

    2018-04-01

    Measured current speed data show that episodes of wind-generated inertial oscillations dominate the current conditions in parts of the northern North Sea. In order to acquire current data of sufficient duration for robust estimation of joint metocean design conditions, such as wind, waves, and currents, a simple model for episodes of wind-generated inertial oscillations is adapted for the northern North Sea. The model is validated with and compared against measured current data at one location in the northern North Sea and found to reproduce the measured maximum current speed in each episode with considerable accuracy. The comparison is further improved when a small general background current is added to the simulated maximum current speeds. Extreme values of measured and simulated current speed are estimated and found to compare well. To assess the robustness of the model and the sensitivity of current conditions from location to location, the validated model is applied at three other locations in the northern North Sea. In general, the simulated maximum current speeds are smaller than the measured, suggesting that wind-generated inertial oscillations are not as prominent at these locations and that other current conditions may be governing. Further analysis of the simulated current speed and joint distribution of wind, waves, and currents for design of offshore structures will be presented in a separate paper.