Vortex shedding analysis by finite elements

Abstract

Despite the rapid progress in numerical fluid dynamics, vortex shedding simulation is still a complicated process requiring its representation by empirical models. The applicability of these models is often restricted, by their inherent non-linearity, to simple beams. The complexities of most structural systems demand an improved generalization of the suggested models and a more representative method of analysis. In this paper, the finite element method in conjunction with Scanlan’s vortex shedding empirical model (used extensively for long-span bridges) is employed to formulate a plane frame element. Based on simple assumptions conforming with the attributes of flow-induced vibrations, the proposed approach is extended further to encompass a space frame element. The developed elements are then used to analyze elementary structures subjected to vortex shedding instability. The vortex shedding oscillatory response is determined by assembling and solving the constituent nonlinear equations of motion using a direct integration scheme and an iterative process. The results verify the validity of the proposed finite element procedure, which should prove to be a flexible means of vortex shedding analysis for more complex structure types.