Wl. Keith et Jj. Barclay, EFFECTS OF A LARGE-EDDY BREAKUP DEVICE ON THE FLUCTUATING WALL-PRESSURE FIELD, Journal of fluids engineering, 115(3), 1993, pp. 389-397
Wall pressure spectra and mean velocity profiles were measured with an
d without a large eddy breakup device (LEBU) located upstream in high
R(theta) turbulent boundary layers. Changes of the order of 5 percent
occurred in the mean wall shear stress. The wall pressure spectra of t
he manipulated flow did not show the existence of any highly energized
coherent structures, but rather moderate changes occurring over broad
frequency ranges. Reductions in the wall pressure autospectra occurre
d at lower frequencies associated with turbulence activity in the oute
r layer and the outer portion of the log law layer. Increases occurred
at higher frequencies associated with the inner portion of the log la
w layer. The changes in the wall pressure coherence levels were simila
r, but generally more complex with greater spatial persistence. The ch
anges in both the autospectra and coherence indicate a conversion of e
nergy from lower to higher convective wavenumbers.