A Physics-Based Model for VIV Analysis

A new hydrodynamic model is presented for analysis and prediction of the response of cylinders undergoing vortex-induced vibration transverse to a free stream. The model is based on the decomposition of the total force into reaction and excitation components respectively acting along the instantaneous relative velocity between the vibrating cylinder and the free stream, and normal to it. The reaction force is modeled via Morison’s equation to introduce fluid inertia due to added mass and fluid damping due to drag. It is verified that the resulting nonlinear model can reproduce the actual response when supplied with measured force coefficients. Model predictions with a set of constant fluid forcing parameters are found to be consistent with empirical formulas for the peak response as a function of the combined mass-damping.