Computer System For Calculation Of Flow,Resistance And Propulsion Of A Ship At TheDesign Stage

Abstract

The computer system executable on personal computers enables determination of flow parameters of a ship with or without a propeller. The system is based on a potential solution of the threedimensional flow around the hull, taking into account the free water surface. The basis of solution is determination of the distribution of Rankine type singularities on the double hull surface discretized by a number of flat panels. After solving the linear boundary condition the system of ship generated waves is obtained through a transformation of the Bernoulli waves. This transformation is based on an original solution of the Green function for a single pressure pulse and equally original method of superposition of such solutions. The propeller is modelled by lifting surface theory and its interaction with the ship is taken into account by including propeller induced velocity in the boundary condition on the hull. The propeller loading is determined by evaluation of total resistance, thrust deduction and wake fraction using a procedure based on theoretical and empirical relations. The system enables determination of the total and wave resistance, wave profile on waterline, streamlines and pressure distribution on the hull surface, wave system on the free surface for a ship model moving with constant speed on calm water.