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

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. Introduction A new hybrid numerical method matches a potential solution at far field with a CFD solution near the structure. In the proposed method, a potential wave solution overlays the outer computational domain of CFD solution, which usually covers diameter less than 10 times of floater footprints. The diffracted waves from the body are absorbed by the momentum and mass source terms applied in the intermediate CFD domain where a viscous-flow solution at near field is gradually blended into the far-field potential solution. The proposed numerical method requires smaller computational domain than the physical wave tank because wave maker and fluid domain near the wave maker do not need to be modeled. The computational domain can be further confined near the floater depending on