Abstract

Wind tunnel experiments up to Mach 3 have provided fluctuating wall-pressure spectra beneath a supersonic turbulent boundary layer to frequencies reaching 400 kHz by combining data from two types of fast-response pressure sensors. Data were corrected for spatial attenuation at high frequencies and for wind-tunnel noise and vibration at low frequencies. A comparison of the pressure fluctuation intensities with fifty years of historical data shows their reported magnitude chiefly is a function of the frequency response of the sensors. The present corrected data yield results in excess of the bulk of the historical data, but uncorrected data are consistent with lower magnitudes, suggesting that much of the historical compressible database may be biased low. The resulting power spectra are used to assess theories for the behavior of boundary layer pressure fluctuations in different frequency ranges. Additional data acquired from a spanwise array of pressure sensors reveal signatures of coherent structures that resemble similar structures known to exist in the velocity field, which provide an explanation for the physical origin of fluctuations at frequencies well below those associated with the boundary layer thickness.

Bio

Steven J. Beresh is a Principal Member of the Technical Staff at Sandia National Laboratories in Albuquerque, New Mexico, U.S.A., where he has worked since 1999 and currently leads the Experimental Aerosciences Facility.  He received his B.S. in Mechanical Engineering from Michigan State University in 1994 and his Ph.D. in Aerospace Engineering from The University of Texas at Austin in 1999.  His research interests emphasize the use of optical diagnostics for compressible aerodynamics research, particularly particle image velocimetry, but further include a variety of instrumentation techniques and physics within compressible fluid dynamics and wind tunnel testing.  He is an Associate Fellow of the American Institute for Aeronautics and Astronautics, serves on the Executive Committee of the Supersonic Tunnel Association International, and is a member of the American Physical Society Division of Fluid Dynamics.