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1

Future research on transonic unsteady aerodynamics and its aeroelastic applications  

Energy Technology Data Exchange (ETDEWEB)

The workshop focused on strategies for promoting and developing engineering level transonic flutter prediction techniques. The technology of transonic aerodynamics is currently undergoing rapid development. Significant progress is being made to solve the inherently nonlinear equations describing unsteady motions of wings in transonic flow, while the availability of reliable and efficient computational methods will greatly enhance the ability to predict the aeroelastic behavior of modern aircraft operating under transonic flow conditions.

1987-08-01

2

Reynolds Number Effects in Transonic Flow  

Science.gov (United States)

... of drag measurements with the AGARD Nozzle Afterbody ... are discussed separately from flows with a ... bubbles introduce typical flow phenomena that ...

1988-12-01

3

Size Effects in Impact Damage of Composite Sandwich Panels Alan ...  

Science.gov (United States)

Wade. Jackson. - Army. VTD at NASA. Langley. ABSTRACT. Panel size has a large effect on the impact response and resultant damage level of honeycomb sandwich ...

4

LPR 3451.1 Effective Date - Langley Management System - NASA  

Science.gov (United States)

Apr 18, 2011 ... TOA period, sick leave may be granted for the period of ..... civil service retirement under the CSRS and FERS retirement programs. ...

5

FOR THIN AND THICK TARGETS - NASA Technical Report Server (NTRS)  

Science.gov (United States)

By W. Wayne Scott. Langley Research Center. SUMMARY. Thin- and thick-target bremsstrahlung spectra are presented for electron energies up to 7.0 MeV. ...

6

Aerosol Education Page - NASA Applied Sciences  

Science.gov (United States)

The NASA Langley Distributed Active Archive Center archives and distributes data relating to Radiation Budget, Clouds, Aerosols, and Troposheric Chemistry.

7

Tests of the ONERA Calibration Models in Three Transonic ...  

Science.gov (United States)

... changes in the wing shock/ separation patterns throughout ... to Reynolds number and tunnel flow quality before ... AGARD Conference Proceedings No ...

1976-11-01

8

GT2003-38839 - Glenn Research Center - NASA  

Science.gov (United States)

indicate incipient flow separation. The peak stagnation line ...... culations of Transonic Fan Performance, AGARD Propul- sion and Energetics Symposium on ...

9

E-11775 Cover set - Glenn Research Center - NASA  

Science.gov (United States)

be due to flow separation and reattachment, rather than transition. The analysis predicted a .... lations of Transonic Fan Performance," AGARD Propulsion ...

10

Calculation and Measurement of Transonic Flows over ...  

Science.gov (United States)

... including those with rear separation, ... flows ibout airfoils." AIAA Paper 'Jo 97-0419, 1987). ... "Effects of streamline curvature on turbulent flow." AGARD ...

1988-10-01

11

The Atmospheric Trace ... - NASA Langley Science Directorate  

Science.gov (United States)

Trace gas molecules absorb specific wavelengths of incoming solar ... These data(with information collected from similar experiments carried on balloons, rockets, ... The ATMOS sensor instrumentis a state-of-the-art version of a 19th century ...

12

Unsteady transonic flow computations for AGARD two dimensional and three dimensional aeroelastic configurations  

Science.gov (United States)

Numerical results on aeroelastic standard configurations are presented. The methods used for two dimensional configurations include the small perturbations approach for inviscid flow, coupling methods for unseparated flow, coupling methods for unseparated or separated, laminar or turbulent boundary layers, and a numerical solution of the Euler equations for inviscid flow. The three dimensional configurations are studied by the transonic small disturbance approach. The detailed results are given.

1986-12-01

13

Aeroelasticity Benchmark ... - NASA Technical Reports Server  

Science.gov (United States)

include modeling geometric complexities, coupling between the flow and the .... noted that the AGARD 445.6 wing data set, which has been widely used for .... higher-level computational aeroelastic code validations at transonic flow separation ...

14

Shock stand-off distance of a solid sphere decelerating in transonic velocity range  

British Library Electronic Table of Contents (United Kingdom)

The shock stand-off distance of a spherical model flying with transonic speeds is determined through numerical simulations. The model decelerates due to drag forces caused by the pressure and viscous shear stress at the model surface. Two-dimensional axisymmetric numerical codes with numerical grids fixed to the flying spherical model are used in the simulations. Numerically determined shock stand-off distances are compared with experimental data obtained in a previous study as well as with those obtained in our ballistic-range experiments. The numerical results and the experimental data are found to be in good agreement. In addition, the time-dependent shock stand-off distance of a decelerating model is investigated.

2011-01-01

15

Instabilities in condensing turbine flows  

Energy Technology Data Exchange (ETDEWEB)

Transonic flows with heat addition due to condensation are important to many technical applications, e.g. to the last stages of large steam turbines, where nucleation and droplet formation become important. Our current research concentrates on the interaction of vortex shedding with condensation in turbines and on rotor/stator interaction in nucleating flows. Both phenomena lead to a significant change of the condensate mass and the droplet radius distribution in the downstream two-phase flow regime. (orig.)

2000-07-01

16

Berechnung Stationaerer und Niederfrequent Instationaerer Stroemungen in Einer Dampfturbinen-Endstufe (Calculation of Stationary and Low Frequency Unsteady Flows in a Steam Turbine End Stage).  

Science.gov (United States)

A numerical method for the calculation of unsteady, inviscid turbomachine flow in the transonic velocity range is described. The calculation of complete stages is possible. If the flow layer geometry is given, the flow field can be determined by independe...

1986-01-01

17

Turbulent break-off flows  

Energy Technology Data Exchange (ETDEWEB)

Different calculated models are presented for turbulent break-off flows and their classification, reflecting the sequence of historical development. The study was done based on equations of viscous liquid of the Navier-Stokes type with development of special phenomenological models of turbulence which take into consideration real properties of the break-off flows based on simpler models of flow presented in the work. In order to calculate two-dimensional turbulent flows, a method of viscous-nonviscous interaction is used. It employs numerical solutions for nonviscous flow and integrated methods of calculating the dissipative region. This method can be extended for calculating the transonic break-off flows, and also break-off in an incompressible fluid when there is cavitation.

1982-01-01

18

Problems encountered in welding Inconel 625 bridgewire material  

Energy Technology Data Exchange (ETDEWEB)

Welding problems occurred while resistance welding Inconel 625 to Inconel 600 pins in the MC3462A header at Unidynamics/Phoenix (UPI). The bridgewire showed transverse and longitudinal cracks, a condition called hot cracking, at the weld area. Welding studies at Mound confirmed a best effort could not produce welds without hot cracking. Two new bridgewire materials, Tophet C and Alloy 800, were then introduced to replace Inconel 625. Samples of both bridgewired headers welded at Unidynamics were studied at Mound to determine which was the better material. Results showed that Alloy 800 was subject to the same hot cracking phenomenon as Inconel 625, whereas all samples of Tophet C except one showed no cracks. The only Tophet C sample showing cracks showed only minor cracks. Langley tests performed with Tophet C as the bridgewire showed that the no-fire characteristics can be met. Tophet C was therefore chosen to replace Inconel 625.

1982-05-10

19

Aerodynamic investigation and modernisation of steam turbine low-pressure components; Aerodynamische Untersuchungen und Modernisierung von Dampfturbinen ND-Teilen  

Energy Technology Data Exchange (ETDEWEB)

This paper provides some results of the research works at low pressure components of steam turbines and some construction solutions resulting in a modernisation. The problems of turbine phases for the transonic flow are analysed with respect to reducing profile and margin losses. The origin and flow of wet steam and its influence on corrosion and erosion is investigated. Inlet and outlet casing of the flow channels and transfer diffuser between second last and last phase are mentioned. (orig.) [Deutsch] Im Beitrag werden einige Ergebnisse der Forschung der Teile von ND-Teilen der Dampfturbinen angegeben, und werden irgendeine Konstruktionsloesungen, die fuer ihre Modernisierung guenstig sind, beschrieben. Kurz wird die Problematik der Turbinenstufen fuer die transsonische Stroemung analysiert, mit Hinsicht auf die Erniederung der Profil- und Randverluste. Weiter ist die Aufmerksamkeit der Entstehung und Stroemung des Nassdampfes im Zusammenhang mit dem Phaenomen ...

1999-12-01

20

Dating divergences in the Fungal Tree of Life: review and new analyses.  

Science.gov (United States)

The collection of papers in this issue of Mycologia documents considerable improvements in taxon sampling and phylogenetic resolution regarding the Fungal Tree of Life. The new data will stimulate new attempts to date divergences and correlate events in fungal evolution with those of other organisms. Here, we review the history of dating fungal divergences by nucleic acid variation and then use a dataset of 50 genes for 25 selected fungi, plants and animals to investigate divergence times in kingdom Fungi. In particular, we test the choice of fossil calibration points on dating divergences in fungi. At the scale of our analysis, substitution rates varied without showing significant within-lineage correlation, so we used the Langley-Fitch method in the R8S package of computer programs to estimate node ages. Different calibration points had a dramatic effect on estimated divergence dates. The estimate for the age of the Ascomycota/Basidiomycota split was 1808000000 y ...