Load and Response Prediction Using Numerical Methods in Acoustic Fatigue

Abstract

A numerical procedure for load and response prediction in the context of acoustic fatigue is investigated on a model problem. Contrary to design guidelines, where the load needs to be specified (for example, based on experiments), the procedure used herein consists of simulating the load with computational fluid dynamics and then using the simulated load as a load input to a finite element simulation of the exposed structure. The model problem studied is a ramped backward-facing step with a thin aluminum panel fitted downstream of the step, parallel to the flow. The vortices generated in the wake of the step impose a time-varying load on the aluminum panel. The numerical results on the load and response are compared to experimental results. The load is simulated with large-eddy simulations with a wall function. The mean reattachment length, load intensity, and spectrum compare well with the measurements, with the exception of a somewhat overpredicted cutoff frequency. The panel response prediction compares reasonably well with the measurements, indicating that there is good potential for the proposed procedure to be used for load and response prediction in the context of acoustic fatigue analysis.