Flow Quality Improvement at Mach 8 in the VKF 50-Inch Hypersonic Wind Tunnel B

Fitch, C R

doi:10.21236/ad0632828

Cited by 4 publications

(4 citation statements)

References 3 publications

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“…FZ and TZ are nondimensional transformed derivatives of the velocity and temperature profiles [27,Eqn. (23,25)]. Figure 39 shows similar results near the nozzle exit.…”

Section: Results At and Near Final Design Point For Prototypementioning

confidence: 58%

“…Standard Langley procedure specifies exotic wall-waviness tolerances of 0.0002 to 0.0005 inch/inch, in designs of axisymmetric quiet-flow nozzles (see, e.g., [68]). According to Ivan Beckwith, these arose from examination of two cases where larger tolerances caused problems with nonuniform mean flow [9,25]. The two-dimensional Mach 3.5 quiet tunnel [9] had a waviness flaw of 0.002 inch/inch, which caused a Mach number variation of 0.045/inch on the centerline.…”

Section: Use Less Exotic Fabrication Processes and Build A Larger Nozzlementioning

confidence: 99%

“…In the axisymmetric case it is well known that any axisymmetric flaws in the nozzle contour create waves that focus on the centerline and therefore create relatively large variations in centerline Mach number. A joint in the original AEDC Tunnel B nozzle caused a Mach number variation from 8 to 7.9 to 8.1 and back to 8; this joint was caused by a maximum wall-waviness defect of about 0.003 inch/inch over 4.8 inches [25]. Figure 6b in [25] shows that the peak Mach number of 8.1 dropped to 8.0 about 1 inch from the centerline of the 48-inch diameter of the nozzle.…”

Section: Use Less Exotic Fabrication Processes and Build A Larger Nozzlementioning

confidence: 99%

“…A joint in the original AEDC Tunnel B nozzle caused a Mach number variation from 8 to 7.9 to 8.1 and back to 8; this joint was caused by a maximum wall-waviness defect of about 0.003 inch/inch over 4.8 inches [25]. Figure 6b in [25] shows that the peak Mach number of 8.1 dropped to 8.0 about 1 inch from the centerline of the 48-inch diameter of the nozzle. The nozzle was remachined to reduce the peak by a factor of 3 or so, to a Mach number variation of 0.01 per inch, with a nozzle waviness of 0.0004 inch per inch.…”

Section: Use Less Exotic Fabrication Processes and Build A Larger Nozzlementioning

confidence: 99%

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Design of a Mach-6 quiet-flow wind-tunnel nozzle using the e**N method for transition estimation

Schneider

1998

36th AIAA Aerospace Sciences Meeting and Exhibit

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A high Reynolds-number Mach-6 quiet-flow windtunnel nozzle has been designed for a new quietflow Ludwieg tube. The quiet-flow nozzle is designed to maintain laminar boundary layers on the nozzle walls as far downstream as possible. A very long nozzle with gentle curvature is used to reduce Görtler instability. Early transition would occur in adiabatic nozzles of this type, due to the first-mode TS instability. This is controlled with an isothermal wall temperature that is high near the throat and tapers to ambient near the exit. The crossflow instability is eliminated through use of an axisymmetric nozzle. Predictions using e N techniques suggest that a quiet-flow Reynolds number in excess of 13 million can be achieved in a 103-inch-long 9-inch-diameter prototype nozzle at 10 atm. total pressure. This performance would be about twice that of the existing Langley Mach-6 quiet-flow nozzle. A 33-foot-long 24-inch nozzle at the same pressure is predicted to have a quiet Reynolds number of more than 36 million, a value sufficient to allow reproducing many flight experiments.

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“…FZ and TZ are nondimensional transformed derivatives of the velocity and temperature profiles [27,Eqn. (23,25)]. Figure 39 shows similar results near the nozzle exit.…”

Section: Results At and Near Final Design Point For Prototypementioning

confidence: 58%