Numerical Simulation of In-Line Response of a Vertical Cylinder in Regular Waves

In-line response of a flexibly mounted, vertical cylinder in a series of regular waves was studied with numerical simulation. A dynamic mesh scheme and a laminar flow model were adopted. The experimental and simulated time histories of five wave gages and the response of the cylinder were compared. At low-incident wave frequencies, although the ratios of the diameters of the cylinders to the wavelength were small, the oscillating cylinder had little influence on the flow field. The numerical responses of the cylinder were in very good agreement with the experimental data. As the frequency of the incoming wave increased, the diffraction effect caused by the cylinder became significant, and the simulated responses of the cylinder were slightly weaker than those of experiment. When the incident wave frequency approached the natural frequency of the cylinder, the cylinder oscillated in resonance, and the flow field was strongly influenced. The wave height behind the cylinder was reduced. At high-incident wave frequencies, the Reynolds number increased, and the numerical response of the cylinder became stronger than those of experiment. In conclusion, the numerical results of the cylinder response agreed well with the results of the experimental model. To improve the predictive accuracy of the numerical model, further study, such as with the use of a turbulence model, should be carried out in the future.