Numerical Simulation Of Submersible Ship During Operation And Calculation Of Motion Of Damaged Ship

This paper analyzed on the floating state,stability,and seakeeping performance of submersible ship in the process of operation.Firstly,the calculation method of the rate of flow of the ship’s ballast pipeline is studied.The flow of the model is calculated by using the CFD commercial software STARCCM+.The results of the numerical calculation are in good agreement with the experimental results.The influence of the geometric parameters of the pipe on the discharge coefficient is also discussed.The time curves of floating state and stability of the ship in the process of sinking are calculated based on the principle of hydrostatics.In this paper,the curve of the capacity of each ballast in each time step is given,and the safety performance of a ship in the case of accident is discussed.Based on the three-dimensional potential flow theory,seakeeping performance of the ship during operation is calculated.Damaged ship motions in waves with are simulated in time domain.The fluid flow in the interior of the tank and the exterior of the ship are modeled and established respectively based on the time domain potential flow theory.The boundary condition of the breakage is determined by Bernoulli equation,and the discharge coefficient at the breakage is obtained by CFD method.The hydrodynamic coefficients of ship in frequency domain is obtained by three dimensional potential flow theory and the retardation function is achieved by the impulse response function method.The tank sloshing forces are instantaneously provided by solving tank fluid flow by Boundary element method.ITTC model PRR01 is used as an example,the motions of model ship in regular waves are simulated.The study shows that the more accurate ship motion time histories are obtained due to taking into account the influence of the internal sloshing forces.The computed results are in good agreement with the experimental data.The present numerical method is of high efficiency,it is a fast and effective approach to estimate motion of damaged ship or submersible ship during operation.