Kyotsuka, Y. [Kyushu University, Fukuoka (Japan); Omori, H.; Nakagawa, H.; Kobayashi, M. [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)
1996-04-10
As one of the environmental problems in sea areas surrounding a very large floating structure (VLFS), change in flow condition is important, and it is one of the factors dominating the prediction of succeeding diffusion and ecosystems. Although a multi-layer model is in wide use for computation of flow condition and diffusion in one inner bay, its applicability should be reexamined because of no consideration of VLFSs. In this study, flow velocity profiles around a barge were then measured through the towing test of a barge in shallow water, and compared with computation results using a multi-layer model. The multi-layer model computed the flow velocity profiles by dividing the flow region to be computed into normal one and that under VLFS, and determined pressures under VLFS by 2-D Poisson`s equation. Slip condition was used as boundary condition at the bottom considering the number of layers under VLFS. Further numerical computation was conducted by 2-D MAC method, in particular, to compare flow around the wake of VLFS with experimental one. Both computation results well agreed with experimental one. 3 refs., 9 figs., 1 tab.
Hu, Changhong; Kyozuka, Y. [Kyushu Univ., Fukuoka (Japan). Graduate School
1996-03-29
Tidal currents and drift currents in a bay with a pontoon type very large floating structure are calculated using a multi-level model. A method of solving two dimensional Poisson equation is proposed to obtain the hydrodynamic pressure under the floating structure. Vertical displacement of the floating structure due to the calculated surrounding water levels can also be calculated. Computation is performed also for tidal flows of a bay to study the effect of the vertical displacement of the pontoon. Lastly, building an airport in the Ariake Sea is assumed as an example, and the effect of the structure on tidal currents is calculated using this method. A floating airport has less effect on tidal currents and residual currents in comparison with a reclaimed island. The horizontal flow velocity under a floating structure increases more than in the case of no platoon, and the effect on the flow rate becomes smaller relatively. There is a little difference in the vertical flow rate between the case of allowing vertical displacement of the platoon and the case of restricting the displacement, but the change in the horizontal flow rate is very little. 5 refs., 11 figs.
Inagaki, M.; Abe, K. [Toyota Central Research and Development Labs., Inc., Aichi (Japan)
1998-07-25
With the recent advances in computers, large eddy simulation (LES) has become applicable to engineering prediction. However, most cases of the engineering applications need to use the nonorthgonal curvilimear coordinate systems. The staggered grids, usually used in LES in the orthgonal coordinates, don`t keep conservative properties in the nonorthgonal curvilinear coordinates. On the other hand, the colocated grids can be applied in the nonorthgonal curvilinear coordinates without losing its conservative properties, although its prediction accuracy isn`t so high as the staggered grid`s in the orthgonal coordinates especially with the coarse grids. In this research, the discretization method of the colocated grids is modified to improve its prediction accuracy. Plane channel flows are simulated on four grids of different resolution using the modified colocated grids and the original colocated grids. The results show that the modified colocated grids have higher accuracy than the original colocated grids. 17 refs., 13 figs., 1 tab.
Takahashi, S. (The Cement Association of Japan, Tokyo (Japan))
1991-10-01
Based on compositional analyses of clinker minerals which have been performed using advanced performance of recent electron probe micro analyzer (EPMA), the relationship between the chemical composition of bulk clinker and chemical composition of clinker mineral is studied again with the purpose of utilizing the correlation for coefficient determination. The basic oxide content and SiO{sub 2} content are established as eigen values. Al{sub 2}O{sub 3} content and Fe{sub 2}O{sub 3} content are determined taking advantage of the correlation of bulk clinker with alite, belite and ferrite concerning Fe{sub 2}O{sub 3} content and Al{sub 2}O{sub 3}/Fe{sub 2}O{sub 3} ratio, and the relationship of constant Al{sub 2}O{sub 3} (aluminate)/Al{sub 2}O{sub 3} (ferrite) ratio (1.31 weight percent) between aluminate with ferrite. The chemical composition of bulk clinker is converted into mineral composition using the obtained 4 content data. 6 refs., 6 figs., 4 tabs.
Ishimatsu, K.; Shinohara, T. (Oita University, Oita (Japan). Faculty of Engineering); Takuma, F. (Kyushu Matsushita Electric Co. Ltd., Tokyo (Japan))
1994-01-25
This paper reports numerical calculations on flow around Savonius wind turbine (rotating) with blades in a semi-circular shape and their output characteristics. The two-dimensional non-compressive Navier-Stokes equations were discretized by a fractional step method with regard to time, and by a finite volume method using non-structural grids with regard to space. Upon the discretization, the flow field in a region 20 times as large as the wind turbine diameter was analyzed for the cases that the Reynolds number is 10[sup 5], the ratios of clearance between two blades to the blade diameter are zero and 0.16, and the circumferential velocity ratio is in a range from 0.25 to 1.75. The paper describes the result as follows: the circumferential velocity ratio when the output is at a maximum is slightly smaller than one, and the circumferential velocity ratio when the output is zero is about 1.7, which agree approximately with values in the previous experiments on the circumferential velocity ratio and output; and vortices are discharged also from rear of the blades in addition to from tips of the blades. Several examples of flow fields as seen from static coordinates are illustrated. 4 refs., 11 figs.
Jardin tähendab aeda / Piret Veigel
Veigel, Piret, 1961-
2004-01-01
Küüni tänava lillekauplusest Tartus. Riiulitel ja seintel on Ester Eddori ja Einike Seido valmistatud lilleseaded ja dekoratsioonid. Lisaks lillemüügile ja seadete valmistamisele korraldatakse teemapäevi
Jardin tähendab aeda / Piret Veigel
Veigel, Piret, 1961-
2004-01-01
Küüni tänava lillekauplusest Tartus. Riiulitel ja seintel on Ester Eddori ja Einike Seido valmistatud lilleseaded ja dekoratsioonid. Lisaks lillemüügile ja seadete valmistamisele korraldatakse teemapäevi
Ishimatsu, K.; Shinohara, T.; Kage, K.; Okubayashi, T. [Oita University, Oita (Japan). Faculty of Engineering
1995-01-25
Considerations have been given on the effects of shed vortices on running performance based on a drawing of the flow fields around a Savonius rotor with semi-circular blades (a drawing depicting the result of calculations using the finite volume method based on two-dimensional incompressible Navier-Stokes equations). A drawing of time-based change in the flow field using a relative velocity vector and an equivalent vorticity line, and a drawing of pressure distribution on the surface of and around the blades were used to indicate that the vortex behavior and the pressure field differ respectively because of increase in the circumferential speed ratio and the existence of blade clearance. The following matters are indicated: the reduction in the torque coefficient in association with increase in the circumferential speed ratio is caused importantly by the separation vortices from the rear face of a leading side blade entering into a concave portion in a return side blade; and the reason for the torque coefficient growing larger above a certain circumferential speed ratio in the case of having blade clearance than the case not having the blade clearance is because the separation vortices from the rear face of the blade become more difficult of entering into the concave portion due to a flow passing through the clearance. 4 refs., 11 figs.
Yasukawa, H. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)
1997-10-01
In order to avoid negative wave resistance (which is physically incomprehensible) generated in calculating wave resistance by using the Rankine source method, a proposal was made on a wave resistance calculation method using the Kochin function which describes behavior of speed potential in regions far apart from a hull. The Baba`s condition was used as a free surface condition for the speed potential which expresses wave motions around a hull. This has allowed a new Kochin function which uses as unknown the speed potential on the hull surface and the free surface near the hull to be defined and combined with the Rankine source method. A comparison was made between the calculated values for wave resistance, hull subsidence and trim change of an ore transporting vessel (SR107 type of ship) in a fully loaded condition and the result of water tank tests. The wave resistance values derived from pressure integration have all become negative when the Froude number is from 0.1 to 0.2, while no negative resistance has appeared in the calculations by using the Kochin function, but the result has agreed with that of the water tank tests. Accuracy of the calculations at low speeds was improved. The trim change in the calculations was slightly smaller than that in the water tank tests. The subsidence showed a good agreement. 7 refs., 1 fig.
Masuda, S.; Kasahara, Y.; Ashidate, I. [NKK Corp., Tokyo (Japan)
1996-12-31
In a high-speed boat of a type using hydrofoils, lifting force increases in proportion to square of its length, while displacement is proportional to the third power. Therefore, an idea has come up that speed of a large boat may be increased by combining the hydrofoils with a submerged body. In other words, the idea is to levitate a ship by using composite support consisting of buoyancy of the submerged body and lifting force caused by the hydrofoils. Insufficiency of the lifting force may be complemented by the buoyancy of the submerged body which increases in an equivalent rate as that in the displacement. However, combining a submerged body with hydrofoils render a problem that lifting force for hydrofoils decreases because of interactions among the submerged body, hydrofoils, and free surface. Therefore, assuming a model of a submerged body with a length of 85 m cruising at 40 kt, analysis was given on decrease in lifting force for hydrofoils due to interactions between the submerged and lifting body and free surface by using the boundary element method. As a result, it was verified that the lifting force for the hydrofoils decreases as a result of creation of a flow that decreases effective angle of attach of the hydrofoils. It was also made clear that making the submerging depth greater reduces the decrease in the lifting force. 9 refs., 14 figs., 1 tab.
Wada, K.; Tsutsui, T. [Mitsui Mineral Development Engineering Co. Ltd., Tokyo (Japan); Ito, T. [Chiba Univ., Chiba (Japan). Faculty of Science; Takeuchi, A. [Toyama University, Toyama (Japan). Faculty of Science; He, P. [Power Reactor and Nuclear fuel Development Corp., Tokyo (Japan)
1997-05-27
With an objective to detect faults estimated to exist along the Shigesumi valley in the Kamioka mine, discussions were given by using electromagnetic survey, which uses the Turam measurement arrangement based on the TEM method, and three-dimensional model calculations. The Turam measurement arrangement, which installs transmission loop fixedly, is used to identify nature and distribution of electrically conductive objects upon noticing abnormal portions in magnetic fields in the measurement data. In the model calculation, the plate model calculation method and the FDTD method were used, and so was the calculation code TEM3DL. The result revealed that strong topographical influence is seen from steep V-shaped valley existing along the traverse line in the measurement data, but an abnormal resistivity band accompanying remarkable distortion in the curve was detected. According to the result of the model calculation, anomaly detection may be found difficult in locations where a low resistivity band has not grown enough locally. It was possible from these facts to assume a model in which the low resistivity band exists directly below the Shigesumi valley, suggesting existence of faults. 2 refs., 8 figs.
Kataoka, M.; Okamoto, Y. [Chiba Institute of Technology, Chiba (Japan); Endo, M.; Noguchi, K. [Waseda University, Tokyo (Japan); Teramachi, Y.; Akabane, H. [University of Industrial Technology, Kanagawa (Japan); Agu, M. [Ibaraki University, Ibaraki (Japan)
1997-05-27
An efficient calculation method of potential distribution in the presence of an embedded body in multi-layer earth has been proposed by expanding the method of image with a consideration of multiple reflection between the ground surface and each underground boundary. For this method, when solving boundary integral equation with the potential of embedded body surface as only one unknown, i.e., when obtaining discretization equation, ordinary boundary element program developed for analyzing the finite closed region can be used. As an example, numerical calculation was conducted for the two-layer earth. The analysis expression of potential distribution in the case of the certain embedded body in two-layer earth has never published. Accordingly, the calculated results were compared with those by the integral equation method. As a result, it was concluded that the primary potential obtained from the present method agreed well with that obtained from the integral equation method. However, there was a disregarded difference in the secondary potential. For confirming the effectiveness, it was necessary to compare with another numerical calculation method, such as finite element method. 5 refs., 5 figs.
Watanabe, T.; Sassa, K. [Kyoto University, Kyoto (Japan); Uesaka, S. [Kyoto University, Kyoto (Japan). Faculty of Engineering
1996-10-01
The effect of initial models on full-wave inversion (FWI) analysis based on acoustic wave-equation was studied for elastic wave tomography of underground structures. At present, travel time inversion using initial motion travel time is generally used, and inverse analysis is conducted using the concept `ray,` assuming very high wave frequency. Although this method can derive stable solutions relatively unaffected by initial model, it uses only the data of initial motion travel time. FWI calculates theoretical waveform at each receiver using all of observed waveforms as data by wave equation modeling where 2-D underground structure is calculated by difference calculus under the assumption that wave propagation is described by wave equation of P wave. Although it is a weak point that FWI is easily affected by noises in an initial model and data, it is featured by high resolution of solutions. This method offers very excellent convergence as a proper initial model is used, resulting in sufficient performance, however, it is strongly affected by initial model. 2 refs., 7 figs., 1 tab.
Shiba, Y.; Okamoto, S. (Taisei Corp., Tokyo (Japan))
1991-10-20
As far as the antiseismic property of the shield tunnel is concerned, the studies has been done in a direction of the longitudinal section in the tunnel so far, and the practical antiseismic calculation methods have been proposed as well. While the studies of the antiseismic property in a direction of cross section have become to be done recently in the processes to design the shield tunnel with a significant importance, the study reports with the earnest efforts are hardly found to elucidate the characteristics of the seismic stresses to develope the rational seismic calculation method. In this report, the practical and simple calculation method of seismic stresses developed in the cross section has been proposed for the shield tunnel excavated in the homogeneous ground. Regarding to the basic idea of this method, the modeling of the tunnel lining was done at first as a ring on the elastic support, and then the stresses developed in the cross section of ring was obtained when the ground displacement and shearing stress, which could be gained from the seismic respond analysis of the natural ground, acted upon it at the responding position of the tunnel. The validity and calculation accuracy have been confirmed by comparing and examing with the dynamic FEM. 15 refs., 8 figs., 4 tabs.
Sugimoto, Y. [DIA Consultants Co. Ltd., Tokyo (Japan)
1998-02-01
A new method to calculate 2.5-D electric potentials around line electrodes in an inhomogeneous medium was developed. While certain conventional analyses of electric potentials due to line sources have assumed that current density is constant along the line source, this assumption is invalid for electrically inhomogeneous media. In the newly developed method, line electrodes are modeled approximately using line elements of 1-D FEM. Since line elements cannot be combined directly with a 2.5-D FEM model, equivalent scattered sources were introduced to evaluate the effect of the line elements on the 2.5-D potentials (equivalent scattered source method). The equivalent scattered sources represent current interchange between the line elements and the 2.5-D FEM elements. A simulation test was carried out and the following results were obtained. 1. In the uniform formation model, potentials calculated by the equivalent scattered source method agreed with the solutions obtained by analytical and charge simulation methods. 2. The results of the equivalent scattered source method indicate that current density increases slightly as depth increases and is concentrated at the tip of the electrode. This phenomenon was also observed in the results of the charge simulation method. Current concentration is considered an effect of the finite radius of the electrode. 3. In the horizontal multi-layered model, calculated current density along line electrodes is inversely proportional to the layer resistivity. 13 refs., 15 figs.
Yamamoto, T.; Nakamura, K. [Osaka University, Tokyo (Japan). Faculty of Engineering
1998-10-25
Start-up flows of viscoelastic fluids in a two-dimensional 4 to 1 abrupt contraction channel is numerically studied and the transient behavior of viscoelastic fluids is discussed. The multi mode Leonov model is applied to describe the rheological properties of the viscoelastic fluid. The numerical simulation has been carried out for two Weissenberg numbers. The following results are obtained from the present analysis: The corner vortices develop with time and restrict the velocity gradient to relax the growth of the stress field. The circular secondary flow works as a stress relief mechanism. The overshoot of the stress growth is observed at the high Weissenberg number and is not done at the low Weissenberg number. This phenomenon is caused by the unsteady elongational property of the fluid. 15 refs., 9 figs.
Yoshizaki, T.; Imanishi, H.; Nishida, K.; Yamashita, H.; Hiroyasu, H.; Kaneda, K. [Hiroshima University, Hiroshima (Japan)
1997-10-01
Three dimensional visualization technique based on volume rendering method has been developed in order to translate calculated results of diesel combustion simulation into realistically spray and flame images. This paper presents an overview of diesel combustion model which has been developed at Hiroshima University, a description of the three dimensional visualization technique, and some examples of spray and flame image generated by this visualization technique. 8 refs., 8 figs., 1 tab.
Sato, M.; Udagawa, M. [Kogakuin University, Tokyo (Japan)
1997-11-25
Calculation time intervals effective in simulating solar DHW systems were discussed, taking into account water temperature in a heat storage tank and calorific power in supplied hot water. The discussion was given on a direct heat collecting system in which heat passes through a heat collector from the bottom of the heat storage tank and returns to the center of the tank, and an indirect heat collecting system which has a heat exchanger built inside the heat storage tank at its bottom. The calculation was performed with time intervals of one to sixty minutes and five to forty-five layer divisions. The following results were obtained: because the calorific power of the hot water supplied is underestimated in the calculation if the calorific power of one hot water supply is extremely large, the calculation time intervals must be reduced to 1 to 15 minutes; cumulative calorific power of the hot water supply was found to show little variation if the number of division is greater than fifteen; and the daily cumulative effective heat collection amount shows very little variation due to the calculation time intervals, but errors from the measured value have decreased as the smaller the number of layer division in the direct heat collecting system, and as the greater the number of division in the indirect heat collecting system. 4 refs., 9 figs., 2 tabs.
Nishimoto, H.; Ogura, R.; Yamazaki, R. [West Japan Fluid Engineering Co. Ltd., Nagasaki (Japan)
1996-04-10
In order to increase a fluid dynamic understanding of the flow field around the measuring part as for the leveling of free surface of the circulated flow tank for measurement, the velocity and free surface profile at the measuring part have been calculated by applying the numerical fluid dynamics. The results were compared with actual phenomena. For the average velocity at the measuring part, inclining angle of surpressing plate, and quantity of water in the tank, the flow field simulation by the numerical fluid dynamics has provided a qualitative agreement with actual phenomena. Especially, it was clarified from the viewpoint of numerical fluid dynamics that the fine adjustment of the inclining angle of surpressing plate and quantity of water in the tank greatly affect the creation of horizontal free surface at the measuring part. Furthermore, effects of the length of measuring part and the ceiling tilt angle of pipe conduit in the downstream of measuring part, which were hard to be analyzed experimentally from the viewpoint of facility and cost, were investigated. Consequently, it was clarified that there are critical length of the measuring part and optimum ceiling tilt angle in the leveling of horizontal free surface. Thus, an instruction for designing was obtained. The present flow field simulation was useful for the fluid dynamic understanding of the flow field at the measuring part, as for the leveling of horizontal free surface. 1 ref., 8 figs.
Fujie, G.; Kasahara, J.; Sato, T.; Mochizuki, K. [The University of Tokyo, Tokyo (Japan). Earthquake Research Institute
1996-05-01
Methods were studied for determining the initial travel time and ray paths with stability when an non-linear travel time inversion is performed in an inhomogeneous structure. The travel time calculation was based on Faria and Stoffa`s method. First, the 2-dimension space was sectioned by grids, and `slowness` was assigned to all the lattice points. Starting from the vibration source, travel time at each lattice point is sequentially calculated. This method calculates travel time for any structure without breakup. In this study, an algorithm more sophisticated than the method of Faria, et al., was developed, and the improvement of travel time calculation accuracy led to the accurate determination of the direction of incidence into the lattice points during the initial motion. The calculation of ray paths was effected by tracing back from the receiving points the incidence into the lattice points or by following back the ray paths to the vibration source. This method performs stable calculation for a heavily inhomogeneous structure and, with the algorithm being simple, do the parallel programming as well. 1 ref., 6 figs., 1 tab.
Saito, H.; Hayashi, K. [OYO Corp., Tokyo (Japan)
1996-05-01
For the purpose of enhancing the efficiency of analytical processes so that those not equipped with high skill may perform a certain level of analysis and that analysis precision may be improved, some analytical techniques based on path calculation were examined. As the result, a flow of work has become feasible, wherein an early model is constructed by use of a tomography-assisted analysis to be accomplished automatedly and the result is then converted into a layer system with the velocity and thickness to be automatically corrected for the determination of the ultimate velocity layer section. Following this flow of work, almost all the parts of the work may be accomplished automatically once the travel time curve is completed. Furthermore, the calculated travel time obtained by this method can be easily compared with the observed travel time creating an opportunity to show the high reliability of this method, for this to be accepted as a standard for evaluating the accuracy of exploration. It has also been found that this method may be applied to more complicated structures which fail to satisfy the conditions for a structure to be treated by other methods such as `Hagiwara`s method.` 3 refs., 5 figs.
Uesaka, S. [Kyoto University, Kyoto (Japan). Faculty of Engineering; Watanabe, T.; Sassa, K. [Kyoto University, Kyoto (Japan)
1997-05-27
Algorithm is constructed and a program developed for a full-wave inversion (FWI) method utilizing the elastic wave equation in seismic exploration. The FWI method is a method for obtaining a physical property distribution using the whole observed waveforms as the data. It is capable of high resolution which is several times smaller than the wavelength since it can handle such phenomena as wave reflection and dispersion. The method for determining the P-wave velocity structure by use of the acoustic wave equation does not provide information about the S-wave velocity since it does not consider S-waves or converted waves. In an analysis using the elastic wave equation, on the other hand, not only P-wave data but also S-wave data can be utilized. In this report, under such circumstances, an inverse analysis algorithm is constructed on the basis of the elastic wave equation, and a basic program is developed. On the basis of the methods of Mora and of Luo and Schuster, the correction factors for P-wave and S-wave velocities are formulated directly from the elastic wave equation. Computations are performed and the effects of the hypocenter frequency and vibration transmission direction are examined. 6 refs., 8 figs.
NONE
1998-03-01
This paper reports a summary of results in fiscal 1997 of research and development of human media technology. Fiscal 1997 launched design and trial fabrication of the following items: interface to improve efficiency and safety of plant operators, accommodation of multimedia contents to aid Kansei design, city development design aiding technologies using contents retrieval and presentation technologies and virtual reality, and empirical evaluation technologies for safety, comfort and convenience. Specific study assignments were extracted on a virtual media technology, a Kansei media technology and a knowledge media technology being three elementary technologies for human media to make clear the research and development approaches to be taken in the coming fiscal years. In addition, a human media technology committee, a research and development working group, and an investigation working group were established. Also launched were investigations on research trends in the human media technology, and investigative researches on contacts of information needs in industries with human media. 59 refs., 114 figs., 24 tabs.
Sasaki, Y. [Kyushu University, Fukuoka (Japan). Faculty of Engineering
1997-05-27
To enhance the reliability of electromagnetic/magnetotelluric (MT) survey, calculation results of finite-element methods (FEMs) and finite difference methods (FDMs) were compared. Accuracy of individual methods and convergence of repitition solution were examined. As a result of the investigation, it was found that appropriate accuracy can be obtained from the edge FEM and FDM for the example of vertical magnetic dipole, and that the best accuracy can be obtained from the FDM among four methods for the example of MT survey. It was revealed that the ICBCG (incomplete Cholesky bi-conjugate gradient) method is an excellent method as a solution method of simultaneous equations from the viewpoint of accuracy and calculation time. For the joint FEM, solutions of SOR method converged for both the examples. It was concluded that the cause of error is not due to the error of numerical calculation, but due to the consideration without discontinuity of electric field. The conditions of coefficient matrix increased with decreasing the frequency, which resulted in the unstable numerical calculation. It would be required to incorporate the constraint in a certain form. 4 refs., 12 figs.
Shinjo, K.; Wakai, T.; Sakai, T. [Hokuriku Electric Power Co., Inc., Toyama (Japan)] Ishii, M. [Tokyo Univ. (Japan)
1997-10-20
Accuracy of an LLP system and a lightning frequency map is evaluated by using transmission line faults in Hokuriku area from November in 1993 to October in 1996. The accuracy and efficiency of the system were calculated by statistical methods. From the above results, the lightning frequency map with 10 minutes meshes was proved capable of replacing the Isokeraunic Level Map with 15 minutes meshes used now for lightning protection design. However, the correlation between the number of detected lightning flashes and transmission line faults in each mesh was found to be week. This result suggests that more detailed analysis taking account of the length of transmission lines in each mesh is necessary. The correlation is stronger in winter than in summer, despite the fact that there is difference in the lightning current distribution in each mesh in winter. This characteristic can be explained if upward flashes from transmission lines are dominant among lightning faults in winter. 19 refs., 11 figs., 6 tabs.
Sekine, T.; Nagae, H. [Nihon University, Tokyo (Japan)
1997-10-01
Recant passenger cars have so higher grades of the cornering performance that the vehicle behaviors at braking in turn have become more important for the security on the obstacle avoidance ability. In this paper, the influences of amount of initial centripetal acceleration to braking motion of vehicles are discussed by experimental and theoretical analysis. Under the higher centripetal accelerations, even smaller deceleration bring the vehicle oscillating yaw velocity phenomena as same as centripetal accelerations. As to advance the effective test procedure. the authors proposed one of the methods that enable to reduce the test error by insufficient vehicle velocity. 7 refs., 6 figs., 1 tab.
Maehara, H.; Iwasaki, T.; Kobayashi, T. [Zexel Corp., Tokyo (Japan)
1997-10-01
A Micro Turbine Sensor has been developed to measure fuel injection quantity and injection rate. Previous reports described results of experiments on the MTS which were carried out under steady and unsteady flow conditions. The MTS has been improved in shape of a holder tip and a detecting procedure for rotating speed of a turbine. As a result revolution speed of the turbine increased 18% over the conventional type holder under steady flow condition. Furthermore the measurement resolution of the MTS came up to about 2(mm{sup 3}/pulse) at 20(mm{sup 3}/stroke) under intermittent spray conditions using fuel injection pump. 11 refs., 11 figs., 1 tab.
Oyama, Y. [Hitachi Car Engineering, Ltd., Tokyo (Japan); Nishimura, Y.; Osuga, M.; Yamauchi, T. [Hitachi, Ltd., Tokyo (Japan)
1997-10-01
Air flow characteristics of hot-wire air flow meters for gasoline fuel-injection systems with supercharging and exhaust gas recycle during transient conditions were investigated to analyze a simple method for calculating air mass in cylinder. It was clarified that the air mass in cylinder could be calculated by compensating for the change of air mass in intake system by using aerodynamic models of intake system. 3 refs., 6 figs., 1 tab.
Yamaya, H.; Naito, Y.; Ishibashi, T. [Kajima Corp., Tokyo (Japan)
1995-12-20
When the dynamic characteristics of structures are identified using data obtained from microtremors or earthquakes as well as from vibration tests with an exciter, the effect of soil-structure interaction on the data together with the effects of disturbances, such as wind force, makes it difficult to identify the characteristics of the structure and soil. A method was previously provided for identifying the characteristics of structure and soil-structure interaction respectively using two-particle systems composed of one particle for the super-structure and another for the base. In this paper, a method is proposed for determining two regression curves with two unknown parameters, i.e., a resonance frequency and a damping ratio, through numeric iteration. At first, parameters were extracted, for which regression curves seem relatively easy to obtain according to the previous discussion, and then, regression curves were calculated by numeric iteration to improve accuracy. Consequently, it was found that regression curves can be used to identify unknown parameters when two among four parameters, i.e., resonance frequencies and damping ratios of super-structure and interaction components, are obtained through experiments. 1 ref., 12 figs., 1 tab.
Oki, Y.; Tanahashi, T. (Keio University, Tokyo (Japan). Faculty of Science and Technology)
1994-05-25
An elucidation has been made on features of two magnetic field analysis schemes in analyzing natural convection in an electromagnetically heated fluid. A quantitative discussion has also been given on the cyclicity inherent to a low-Prandtl number fluid. Twin vortices in an induced magnetic field at the center of a square cavity had Lorentz force that accelerates convection acted on them. However, as the magnetic field strength increases, the twin vortices have disappeared, with only the secondary vortices remaining on four corners of the cavity where Lorentz force that suppresses convection acts on. The motion energy and the frequency characteristics of fluid magnetic cross helicity have verified quantitatively how a flow transfers from a cyclic flow to a steady flow as the magnetic field strength increases. It was indicated that the numerical residual method has superior convergence in solution of Poisson equations except for the initial stage under a weak magnetic field to the cross helicity. It was also shown that the numerical residual method has superior solution convergence from the initial stage under a strong magnetic field. Particularly for the case with large Joule heat generation, degradation in the calculation efficiency for the numerical residual method is more remarkable than in the cross helicity method. 8 refs., 10 figs.
Yamagami, Y.; Tani, T. [Science University of Tokyo, Tokyo (Japan)
1996-10-27
Based on the basic quality equation of photovoltaic (PV) cell, a quality equation of PV module has been constructed by considering the spectral distribution of solar radiation and its intensity. A calculation method has been also proposed for determining the output from current-voltage (I-V) curves. Effectiveness of this method was examined by comparing calculated results and observed results. Amorphous Si (a-Si) and polycrystal Si PV modules were examined. By considering the environmental factors, differences of the annual output between the calculated and observed values were reduced from 2.50% to 0.95% for the a-Si PV module, and from 2.52% to 1.24% for the polycrystal Si PV module, which resulted in the reduction more than 50%. For the a-Si PV module, the environmental factor most greatly affecting the annual output was the spectral distribution of solar radiation, which was 3.86 times as large as the cell temperature, and 1.04 times as large as the intensity of solar radiation. For the polycrystal PV module, the environmental factor most greatly affecting the annual output was the cell temperature, which was 7.05 times as large as the spectral distribution of solar radiation, and 1.74 times as large as the intensity of solar radiation. 6 refs., 4 figs., 1 tab.