Numerical simulation into the drag characteristics of symmetrical and asymmetrical catamarans with various demihull separations

This paper describes the numerical prediction of resistance for symmetrical and asymmetrical catamaran with various demihull separations (S/L). Numerical simulations have been carried out to determine the incompressible free surface flow around the demihull form for which experimental results are available. The model involves the numerical solution of the Reynolds Averaged Navier-Stokes (RANS) equations along with the Volume of Fluid (VOF) method for predicting the free surface. The shear stress transport (SST) turbulence model has been used in the viscous flow code and a tetrahedral unstructured grid was applied for meshing the computational domain. The verification was based on the examination of the flow around the hull for range of speeds and by comparison of the results for resistance obtained by CFD simulations and by experiments and other published information. This study shows that numerical investigation appears to provide very good agreement as has been observed in the resistance curves showing that CFD methods may adequately deal with the problem of resistance interference produced by both demihulls.