Simulation Strategy And Motion Response Analysis Of Ship's 3D Hydrodynamic Impulse Response Function

Time domain prediction of ship motion in waves is one of the development trends of ship hydrodynamics,and it is a hot spot in the field of ship and sea engineering.However,hydrodynamic seakeeping currently no proprietary software.This paper is based on "numerical pool" technology R & D team put forward the impulse response function and the Taylor expansion based on boundary element method for ship hydrodynamics and motion simulation,using the impulse response function method,in the same wave conditions can be computed once the impulse response function,which greatly improves the calculation efficiency;and use the Taylor expansion to solve the time domain boundary element method Rankine source of traditional simulation of ship motion are stepping instability problems.Based on the above method theory,the following research work is carried out:1.The mathematical expression of steady potential and unsteady potential solution for ships moving in waves at speed is given.Through three-dimensional hydrodynamic impulse response function,the problem of definite solution is solved.Then Taylor expansion boundary element method is applied to solve the boundary integral equation.It provides a theoretical basis for the subsequent numerical simulation.2.Examples of WIGLEY-A ship,WIGLEY-B ship and S175 ship,calculation of ship hydrodynamic coefficients(added mass coefficient and wave damping coefficient),F-K force and diffraction wave force impulse response function,and compared with other methods,verify the correctness of the calculation of hydrodynamic impulse response function.3.The WIGLEY-A ship,S175 ship and KCS ship for example analysis of the sensitivity of the following parameters,including the selection of NK and DB assumptions;spatial discrete parameters: the size of the computational domain,and the free surface,surface mesh density,surface mesh density;time discrete parameters: the impulse response function to calculate the total time,the impulse response function of time step step.A set of setting parameters is summarized.At the same time,the two ship set different speed calculation to verify the set of parameters is also applicable to different speed.4.A set of non setting parameters that are applicable to different ships at different speeds are calculated by using the above mentioned set up parameters.The S60 ships,KVLCC2 ships and WIGLEY-B ships are calculated and compared with the experimental values.The calculation results of the WIGLEY-B type ship are compared with that of Masashi Kashiwagi.Both the calculated results of ship hydrodynamic coefficients and ship motion are better than those of the latter,which verifies the advanced nature of the calculation method in this paper.