Unit-cell finite element analysis of the response of complex structures to flow excitation

Abstract

Analytic estimation of the vibration response of rib-reinforced structures excited by turbulent boundary layer (TBL) wall pressure fluctuations is a subject of ongoing interest for numerous applications in airborne and underwater acoustics. Previous investigators have developed a variety of closed form and approximate analytic methods for estimating the response of structures of interest. Fluid-loading and rib-reinforcement effects make problems involving the response of sea-going vessels particularly challenging. Recent advances in finite element based methods and the enhanced capabilities of modern computer hardware now permit the application of the FEA method to such flow-induced vibration problems. This paper describes the application of the unit-cell capability in BBN’s SARA-2D finite element code to evaluate the response of fluid-loaded, rib-reinforced cylinders to TBL excitation. An overview of the unit-cell modeling method is presented, and example results are provided to illustrate the effects of variations in rib and shell dimensions.