COMPUTATION OF VORTEX INDUCED VIBRATION AND THE EFFECT OF CORRELATION ON CIRCULAR CYLINDERS IN OSCILLATORY FLOW

A numerical method for the computation of vortex shedding induced vibration is presented. The method is a discrete vortex method based on operator splitting, random walk and vortex-in-cell techniques originally developed by Stansby and Dixon (1983) at University of Manchester. Simulation of the oscillatory flow around a flexibly mounted rigid cylinder is carried out. The results are compared with experiments (Bearman et Hall 1987). The 2-dimensional fluid loading method is then applied by a strip theory formulation for a number of sections along the same flexibly mounted rigid cylinder. The different sections are hydrodynamically uncoupled. When the cylinder starts to oscillate, the correlation between the transverse forces for each section increases, due to the motion of the cylinder only. The effect of correlation on vibration amplitudes is shown. The method is also compared with experiments for prescribed displacement of a model riser in still water (Lyons and Patel 1987).