Supersonic Low Disturbance TunnelNASA Langley Research Center |
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| The Langley Supersonic Low-Disturbance Tunnel (SLDT) provides a low-disturbance free- stream environment for high-speed transition research. It is a blowdown tunnel that uses dry air that is filtered to exclude particles 1 micrometer and greater in size. The tunnel exhausts to vacuum spheres or the atmosphere and provides typical run times of 30 to 45 min. Stagnation pressures from 5 to 175 psia are possible at a free-stream Mach number of 3.5. The settling chamber contains seven antiturbulence screens along with a number of dense, porous plates that function as acoustic baffles to attenuate incoming pressure fluctuations. The nozzle-wall boundary layer is maintained laminar to high unit Reynolds numbers through the use of (1) boundary-layer removal slots just upstream of the nozzle throat and (2) a properly tailored nozzle expansion with highly polished walls. The two-dimensional nozzle is approximately 15 in. long and has an exit size of 10 in. wide by 6 in. high. It is configured as an open jet exhausting into a straight pipe diffuser. The quiet uniform-flow region within the nozzle is bounded downstream by eddy-Mach-wave radiation from transition or turbulence on the nozzle walls. The quiet region is 5 to 12 in. long, 7 in. wide at the upstream end, and 2 to 4 in. high. The test volume decreases with increasing unit Reynolds number. The magnitude of pressure fluctuations in the quiet region is less than 0.1 percent of the free-stream static pressure. The maximum quiet-length Reynolds number is approximately 8 x 106. |
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Trademark Disclaimer: The use of trademarks or names of manufacturers in this report is for accurate reporting and does not constitute an official endorsement, either expressed or implied, of such products or manufacturers by the National Aeronautics and Space Administration. |
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| For more information contact: The Supersonic Low Disturbance Tunnel Manager -- NASA Langley Research Center -- Hampton, Virginia 23681-2199 phone: 757 ° 864 ° 2159 | fax: 757 ° 864 ° 7897 | e-mail: wte+ fm_sldt@larc. nasa. gov |
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| NASA Official Responsible For Content: Pete Jacobs |
Page Curator: CONITS Development Team | Date Last Updated:11/17/2005 |