Sound transmission and radiation from a plate-cavity system in supersonic flow

Noise transmission into and radiation from a rectangular cavity through a flexible structure in a noisy/thermal environment at supersonic flow is studied. Most works in acoustic fluid/solid interaction have focused on linear models in the preflutter domain (stable region). In this paper, the pre-/postflutter regions are considered in a nonlinear study. The governing equations of a flexible panel are constructed using the von Kármán theory, the firstorder piston theory, and a modal cavity formulation; also, a stationary-homogenous turbulent boundary layer is modeled based on experimental data through stochastic modeling. The thermal environment and external incident random noise are also considered, and the far-field sound is predicted with a boundary integral method. The Rayleigh-Ritz approach is adopted to discretize the partial differential equations of the acoustic fluid/solid interaction system, and the resulting ordinary differential equations are solved numerically by the fourth-order Runge-Kutta method. In the postflutter domain, the acoustic pressure in the cavity is nearly spatially uniform and has the highest sound pressure levels in the lower-frequency regions. In-plane thermal loading may increase the dominant frequency of the sound field, but it may decrease or increase the sound pressure level. Higher cavity modes are excited by the turbulent boundary layer and the incident random load in the preflutter domain.

Duke Scholars

Author Earl H. Dowell Thomas Lord Department of Mechanical Engineering and Materia ...