Numerical Simulation Of Ship Motion In Waves With Tank Sloshing

By studying the coupling characteristics of ship wave motion and tank sloshing,this paper presents a numerical algorithm program.When studying ship wave motion and tank sloshing motion,based on potential flow theory,the fluid is assumed to be an ideal fluid that satisfies the continuity equation.The boundary conditions of the computational domain are derived,and the boundary value problem of the watershed is discretized using the Green’s function method combined with the boundary integral equation.In order to make the numerical simulation more in line with the actual situation,the boundary conditions of the object surface were corrected by adding an artificial damping correction term.Finally,based on the velocity potential field distribution within the computational domain,the hydrodynamic characteristic parameters of ship wave motion and coupled motion are solved.Based on the above theoretical calculation process,compile the coupled motion response numerical calculation program FHLAN.In order to verify the results of the numerical program,a comparative study was conducted with the calculation results of the commercial software WADAM,and the hydrodynamic characteristic parameter results between the two were consistent.Based on this numerical program,the effects of damping coefficient,tank loading rate,tank position arrangement,and distance between two tanks on coupled motion response were further analyzed.The research results are as follows:(1)In the study of ship wave motion characteristics,the free surface Green’s function is used to discretize the boundary value problem by distributing singular points on the object surface.A study was conducted on the numerical solution of the free surface Green’s function.The article compared the similarities and differences between the numerical integration method and the Newman algorithm.The research results showed that the computational accuracy of the two algorithms was not significantly different,with a maximum error of 0.1.The average computational efficiency difference between the two is 4.794 times,with a maximum efficiency difference of 4.794 times and a minimum efficiency difference of 2.726 times in each partition.(2)Further research was conducted on the coupled response characteristics of tank sloshing and ship wave motion.In the study of coupled motion response characteristics of single tank sloshing,when the loading rate is less than 50%,the tank sloshing will increase the peak value of the coupled motion RAO curve,and as the loading rate continues to increase,the peak value of the coupled motion RAO curve will continue to increase.The peak value of the coupled motion RAO curve under dual tanks does not change significantly with the loading rate.The different values of damping coefficient have little effect on the coupled motion characteristics of ships under the influence of tank sloshing.Under a single tank,when the position of the tank is arranged at the center of gravity of the ship,the effect on the coupled motion of the ship is minimal,while under a double tank,when the tank is arranged about the center of gravity of the ship,the spacing between the tanks has little effect on the coupled motion of the ship.