The Design of Large High-Speed Wind Tunnels
Explore the source record for details and available documents.
SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Data obtained from a wind tunnel test of an 0.015-scale 140 A/B configuration space shuttle vehicle orbiter model (49-0) are presented. Runs were conducted at Mach numbers 0.6, 0.9, 1.2, 1.6, and 2.0 and Reynolds numbers of 8.4, 9.0, 9.0, 10.9, and 13.6 million per foot respectively. Various control surface settings were investigated from angles of attack of minus 4 degrees to plus 30 degrees at fixed angles of sideslip of zero and minus 5 degrees and through angles of sideslip from minus 2 to plus 8 degrees at fixed angles of attack of zero, plus 10, plus 15, and plus 20 degrees. The purpose of the test was to define the longitudinal and lateral-directional stability and control characteristics for the updated SSV configuration.
Explore the source record for details and available documents.
Vertical axis wind turbine incorporates several unique features to extract more energy from wind increasing efficiency 20% over conventional propeller driven units. System also features devices that utilize solar energy or chimney effluents during periods of no wind.
Indications of the climatological distribution of wind shear and temperature lapse and inversion rates as observed by rawinsonde measurements over the western United States are recorded. Frequencies of the strongest shear, lapse rates, and inversion layer strengths were observed for a 1 year period of record and were tabulated for the lower troposphere, the upper troposphere, and five altitude intervals in the lower stratosphere. Selected bivariate frequencies were also tabulated. Strong wind shears, lapse rates, and inversion are observed less frequently as altitude increases from 175 millibars to 20 millibars. On a seasonal basis the frequencies were higher in winter than in summer except for minor influences due to increased tropopause altitude in summer and the stratospheric wind reversal in the spring and fall.
The continuum spectrum of the flickering blue variable RW Sex was observed from 10,000 to 1150 A. The star is a cataclysmic variable currently stabilized at maximum, and the spectrum is dominated by an accretion disk, with flat spectrum in the ultraviolet, except at more than 5000 A, where a blackbody near 7000 K is seen. A distance of 400 pc is derived, if the latter arises from an F type main sequence star. The accretion rate required is near 10 to the -8th solar masses per year. Only weak emission is seen, except for Lyman alpha; strong, broad UV absorption lines are seen with centers displaced up to -3000 km/s, with terminal velocities up to -4500 km/s, the velocity of escape from a white dwarf. The low X-ray flux may arise from absorption within an unusually dense, hot wind from the innermost portions of the disk. The estimated mass loss rate is nearly 10 to the -12th solar masses per year.
Aerodynamic tests in wind tunnels are jeopardized by the lateral limitations of the throat. This influence expands with increasing size of the model in proportion to the cross-section of the throat. Wall interference of this type can be avoided by giving the wall the form of a stream surface that would be identical to the one observed during free flight. To solve this problem, flexible walls that can adapt to every contour of surface flow are needed.
The technical requirements and test data from the Mach 3.5 Pilot Low-Disturbance Tunnel are presented. This unique facility provides a test region with essentially zero-acoustic noise and simulates, for the first time, the low-disturbance conditions of atmospheric flight. Applications to the test results of linear stability theory with the e exp N method indicate that transition locations for both simple and complex flows are well predicted by using N of about 9 to 11.
The plans for the wind tunnel at Issey-les-Moulineaux are discussed in relation to concerns about the Law of Similitude and propeller speed.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Wind tunnel construction and design is discussed especially in relation to subsonic and supersonic speeds. Reynolds Numbers and the theory of compressible flows are also taken into consideration in designing new tunnels.
A wind-tunnel investigation of a 0.049-scale model of the Boeing XB-52 airplane was made at Mach numbers from 0.30 to 0.925 and at corresponding Reynolds numbers from about 2.3 x 10(exp 6) to 4.3 x 10(exp 6). The results of the investigation indicate satisfactory static longitudinal stability throughout the test Mach-number range and some loss in tail effectiveness beginning at about 0.80 Mach number. A comparison of the results of these tests with those of the same model in the Boeing Airplane Company's wind tunnel showed close agreement of lift- and drag-divergence Mach numbers. Slight differences were observed in tail effectiveness and the position of the stick-fixed neutral point.