Computation of Wave-Making Resistance of Multihulls Using a Surface Panel Method

Abstract

The thesis presents a potential based boundary element method for calculating the flow around the multihull ships moving with a uniform speed in unbounded water. The ship-wave problem is a non-linear one due to the non-linear nature of free surface boundary condition. In order to solve the problem, the free surface condition is linearized first about the mean water level by the systematic method of perturbation in terms of a small parameter. The distributions of singularities on the surfaces are determined by satisfying the linearized free surface condition and the kinematic conditions on the hull surface respectively. The circulation is introduced to generate lift by distributing doublets on the wake surface and is determined by applying the Kutta condition at the trailing edge of the lifting part. The present method has been applied to a number of multihulls for various Froude numbers and is found to be efficient for evaluating flow field, wave pattern and wave making resistance in unbounded water.