Currently there is a substantial lack of data for interactions of shock waves with particle fields having volume fractions residing between the dilute and granular regimes. To close this gap, a novel multiphase shock tube has been constructed to drive a planar shock wave into a dense gas-solid field of particles. A nearly spatially isotropic field of particles is generated in the test section by a gravity-fed method that results in a spanwise curtain of spherical 100-micron particles having a volume fraction of about 20%. Interactions with incident shock Mach numbers of 1.66, 1.92, and 2.02 are reported. High-speed schlieren imaging simultaneous with high-frequency wall pressure measurements are used to reveal the complex wave structure associated with the interaction. Following incident shock impingement, transmitted and reflected shocks are observed, which lead to differences in particle drag across the streamwise dimension of the curtain. Shortly thereafter, the particle field begins to propagate downstream and spread. For all three Mach numbers tested, the energy and momentum fluxes in the induced flow far downstream are reduced about 30-40% by the presence of the particle field.

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.

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