Two-component filtered planar velocimetry in the compressible turbulent boundary layer

FilteredPlanar Velocimetry (FPV) has been employed to obtain nonintrusive, instantaneous, planar measurements of streamwise and spanwise velocities in the compressible, turbulent boundary layer. Measurements were obtained in a fullydeveloped Mach 3 flat plate boundary layer and the nonequilibrium boundary layers obtained by subjecting the flat plate boundary layer to expansion corners of 7°and 14°. The FPV results were compared to measurements obtained with Laser Doppler Velocimetry. Although uncertainties associated with the FPV technique preclude detailed investigations of the boundary layer turbulence, mean velocity profiles measuredwith FPV and LDV exhibit very good agreement. As expected, near-zero spanwise velocities were measured in the two-dimensional flow field. The FPV technique provides much better near-wall resolution than LDV. FPV measurements were obtained to within 0.4 mm of the surface while LDV measurements could be acquired only to within approximately 2.0 mm of the surface.