The Prediction Of Ship Wave-making Resistance By Panel Method

How to improve the ship speed is the chief problem in the ship designing. In a certain range of Froude number, the wave-making resistance is very sensitive to the ship fullness and other details in the ship designing, the wave-making resistance can be reduced obviously by suitable modification of the ship type. By this characteristic, the calculation of wave-making resistance turns into the important aspect of ship optimization design. So many researchers and research organizations regard the surface-ship wave problem as an important problem.Accompanied by the rising of high-speed ship, the typical linear wave theory gets new application. So adopting the linear wave theory to predict the wave-making resistance quickly and accurately is adaptive to the modern production demand, it is also the basis of the ship type modification and the ship optimization design.The ship wave problem for a ship traveling in a uniform flow is solved by the panel method based on Kelvin source in this paper. The mathematical model constructs on the linear wave theory, the hull is discretized into a number of panels with Kelvin source distribution, and the kinematic condition is satisfied exactly on the wet ship body, it is a improved way to the traditional linear wave theory which displays the source on the longitudinal mid-section.The key question in the numerical calculating of wave problem is the calculation of the induced coefficient between each panel, where the most difficult question consists in is the realization of the derivative of the wave function and its integral on a panel and a line. So the main work of this paper is to quickly and accurately solve the integral of the derivative. The subsection integral is used to get a simpler function at first, and the Gauss integral is used to get the integral on the panel and the line, then the complexity and the instability in the numerical calculation as a result of the high frequency surge function can be avoid.As a application of the method, the wave height of point source, panel source , the Wigely ship and its wave-making resistance coefficient are calculated. Thenumerical results from this paper are satisfactory with experimental data and other results of references. Furthermore, the change of the step of 9 integral, the Gauss node number and the disperse method of free surface are studied here to improve the precision and the speed of this method, so it can be used to modify the ship line and optimize the ship design.