Anisotropic grid adaptation for RANS simulation of a fast manoeuvring catamaran
4th High Performance Yacht Design Conference, 11th-12th March 2012, Auckland, New Zealand.
Using automatic grid refinement in the context of ship flow simulation puts several specific requirements on the mesh refinement method. An adaptive grid refinement method has been developed for the FINE™/Marine solver, the unstructured Reynolds-averaged Navier-Stokes solver developed by the Numerical Modelling group of LMF. This commercialised flow solver is aimed at the simulation of realistic flow problems in all branches of marine hydrodynamics. The refinement method thus features anisotropic refinement on unstructured hexahedral grids, derefinement of previous refinements to enable unsteady flow computation. Every step of the anisotropic grid adaptation is parallelised with the use of an integrated dynamic load balancing procedure which moves points from one block to the others to maintain during the computation a perfect load balance. This paper presents simulations of the flow on the Delft372 catamaran form developed by TU Delft. The study is part of the NATO AVT-161 “Assessment of Stability and Control Prediction Methods for NATO Air & Sea Vehicles” working group to assess the feasibility of various computational tools for modern design of air, land or seagoing vehicles. The focus of the present study is on maneuvering of fast catamarans. We demonstrate how anisotropic refinement can possibility be used to compute the main flow features including possible ventilation at high Froude number at forced drift with a local accuracy unreachable on grids a priori built without the knowledge of these tiny flow features.
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