Vibrational response of water‐loaded flat plate to a turbulent boundary layer pressure field

Abstract

The vibrational response of a 1.2‐ × 40‐ × 200‐mm flush‐mounted flat plate, with heavy accelerometers attached to the backside, to a turbulent boundary layer (TBL) pressure field was measured at several flow velocities in a 190‐ × 190‐mm low noise water tunnel. The measured response spectra of the water‐loaded stainless steel flat plate was compared with the calculated response in the 400‐ to 1500‐Hz frequency range using the plate modal properties and the pressure spectra. The phase indicated convection velocity varied with separation and frequency and was accounted for in the plate response calculations. The plate modal properties were obtained experimentally by in situ modal analysis and the plate was found to have a large number of heavily damped modes in the same frequency range. The turbulent boundary layer pressure field driving the plate was measured upstream and downstream from the plate and was found to be unaffected by the vibrating plate. The two‐point pressure cross spectra at the wall for the TBL were found to vary with the axial and transverse separations in a way similar to that of the Corcos similarity model and followed the multiplication hypothesis but had a different form of explicit dependence upon the separation.