HYDRODYNAMICAL DESIGN OF SUPER-SLENDER-TWIN-HULL FERRIES BY CFD TECHNIQUES

Two CFD techniques are applied in the course of developing a new-type of fast ferry known as super-slender-twin-hull. Since this ship is of the displacement type and the design Froude number is from 0.4 to 0.8, minimization of wave resistance is of major importance. For a hull form of minimum resistance the TUMMAC-IV method for ship waves is employed. By imposing appropriate boundary conditions on the centreline and the bottom the wave system of a catamaran in both deep and shallow waters is simulated. For the design of the afterbody, the WISDAM-V method which employs the boundary-fitted coordinate system and finite volume discretization is used. The difference of the bottom flow due to shortening the length of the after body, the effect of waves on the viscous flow, the effect of the asymmetric hull geometry on the wake are studies. The oblique tow simulation is performed with this method by giving proper inflow boundary conditions. It is demonstrated that the method can correctly predict lateral force and yaw moment.