Numerical Wave Tank Analysis of Wave Run-Up on a Truncated Vertical Cylinder

Abstract

A new far-field closure condition for a CFD-based numerical wave tank that uses a potential wave solution to overlay the outer computational domain of a CFD solution is described. A prescribed potential wave solution covers the region beyond a diameter more than 10 times of floater footprints. The diffracted waves from the body are absorbed by the ‘potential-attractor’ terms applied in the intermediate CFD domain where the CFD solution for Navier-Stokes equation is gradually blended into far-field potential solution. The proposed model provides an efficient numerical wave tank for the case when incoming wave length is much longer than floater. In this case, the required mesh and domain size for numerical accuracy is mainly affected by the floater geometry and local wave kinematics near the floater and less dependent on the length scale of the incoming waves. The new numerical wave tank is first tested for a diffraction of a truncated cylinder exposed to long regular waves. Comparison with theoretical and experimental results demonstrates accuracy and efficiency of the new method.