Bm. Abraham et Wl. Keith, DIRECT MEASUREMENTS OF TURBULENT BOUNDARY-LAYER WALL-PRESSURE WAVE-NUMBER-FREQUENCY SPECTRA, Journal of fluids engineering, 120(1), 1998, pp. 29-39
Direct measurements of streamwise wavenumber-frequency spectra of turb
ulent wall pressure fluctuations were made in an acoustically quiet wa
ter tunnel. A linear army of evenly spaced flush mounted pressure sens
ors was used to measure the wall pressure field at 48 streamwise locat
ions. This array provided over 24 dB of resolution resolution (sidelob
e rejection) in the wavenumber domain, leading to an accurate estimate
of the ''convective ridge'' and part of the subconvective and low wav
enumber portions of the spectrum at discrete frequencies. Boundary lay
er parameters, including the mean wall shear stress, boundary layer th
ickness, displacement thickness, and momentum thickness, were derived
from mean streamwise velocity measurements for 8100 < R-theta < 16, 70
0. Time and length scales derived from these parameters were used to n
ondimensionalize the measured spectra. The effectiveness of different
scalings for nondimensionalizing the low and convective wavenumber reg
ions at discrete frequencies was evaluated.