A wavenumber analysis of the coupling of a structural mode and flow turbulence

Previous studies of the coupling of a structural mode and the pressure field induced by a highly subsonic turbulent boundary layer have been concentrated on the determination of the relative contributions by two regions of the wavenumber domain: the high-wavenumber region, at and near the hydrodynamic coincidence, and the low-wavenumber region, at and near the modal wavenumber. The corresponding contribution to the coupling by the intermediate-wavenumber region that lies between the high- and low-wavenumber regions has not received proper attention. In this paper, formulae to estimate the contributions to the coupling by the three wavenumber regions are derived for some homogeneous structural panels with various boundary conditions, and numerical results are evaluated and compared. The relative contributions to the coupling among the three wavenumber regions vary with boundary condition, mode order number, and the ratio of the structural free wavenumber and the convective wavenumber at the modal resonance frequency. It is found that situations exist in which the contribution by the intermediate-wavenumber region may be significant.