Analysis of Hydroelastic Instabilities of Rectangular Parallel-Plate Assemblies

Flow-induced vibrations and hydroelastic instabilities of rectangular parallel-plate assemblies are studied theoretically. The extended Galerkin method is employed to solve the plate equation, while the Fourier transform technique is used to solve for the perturbation pressure from the potential flow equations. The mixed fluid-plate interaction boundary condition leads to a singular integral equation, which is solved numerically. The complex frequencies versus flow velocity and critical velocities are obtained for various plate aspect ratios and channel-height-to-plate-width ratios. The frequencies and critical velocities are found to decrease as the plate length increases and as the channel height decreases. Two types of instability are found, namely, single-mode divergence, mostly in the first mode, and coupled-mode flutter involving adjacent modes. Damping has a significant effect on post-divergence stability and coupled-mode flutter of the system. [S0094-9930(00)00403-0]