Separated flow surface pressure fluctuations and pressure-velocity correlations on prolate spheroid

Power spectra of turbulent surface pressure fluctuations and spatial correl ation coefficients of surface pressure-velocity are presented for the leesi de, three-dimensional, separated crossflow over a 6:1 prolate spheroid at R e-L = 4.2 x 10(6) for angles of attack of 10 and 20 deg. This is a complex, three-dimensional, nonequilibrium Row of practical interest. These results are related to the attached, separated, and reattached features of the vor tical flow for a range of Reynolds numbers based on momentum thickness up t o 1.5 x 10(4). The high-frequency surface pressure fluctuation spectra scal e on walt variables at low angle of attack, Near regions of separation wher e wall shear stress is low, there is little high-frequency content, whereas low-frequency contributions from the cuter layer are relatively large. in regions with large surface shearing stresses, the wall region produces stro ng, high-frequency spectral content. At locations with relatively small out er region mean velocity gradients, there are smaller low-frequency contribu tions. Both of these features occur around the side of the body and under t he large vortices at higher angle of attack. Therefore, at these locations spectral values are nearly constant at middle frequencies. The resulting rm s pressure fluctuation distributions over the surface reflect the importanc e of the high-frequency wall region contributions. Around regions of bounda ry-layer separation there are local minima in ms pressure fluctuations, whe reas around reattachments and under the large vortices there are local maxi ma in rms pressure fluctuations.