Measurement of noise radiated by boundary layer excited panels

Abstract Measurements are reported of the sound power radiated by panels excited by a turbulent boundary layer. Aluminium panels of four thicknesses were tested: 0·020, 0·040, 0·060 and 0·080 in. Each panel was mounted in the test section of an acoustically quieted air duct which was enclosed in a concrete reverberation room. The ratio of the rms turbulent pressure fluctuation measured on the rigid wall to the local shear stress varied from 2·8 at Mach 0·3 to 3·3 at Mach 0·78. The mean square displacement of the thinnest panel exhibits a substantially different behavior from the 0·080-in. panel. This difference is manifested in the acoustic power radiated. The power radiated varies from M5h−1·6 to M2·3h−1 for the 0·020, 0·040 and 0·060 panel while the 0·080 follows to the M5 relationship for all Mach numbers.