Study On The Coupling Effect Between Liquid Sloshing And Tank Motion During Loading

Filling a ship’s tank with liquid is a common operation during ship operation.In this process,complex motions such as the impact of the filling of the liquid into the tank,the sloshing of the liquid in the tank,and the movement of the tank are coupled.Based on CFD numerical simulation and model test methods,Based on CFD numerical simulation and model test method,the coupling effect of liquid sloshing and tank motion during filling process is studied.Firstly,numerical simulation is used to study the effect of filling on liquid sloshing in the forced shaking tank;secondly,the physical model test is used to study the influence of filling speed and initial liquid loading rate on liquid sloshing and tank motion;finally,CFD technology is used to simulate static the roll attenuation motion of the tank in the water,and the influence of the initial heel angle on the liquid sloshing is analyzed.The specific work content and results are as follows:(1)By virtue of the STAR-CCM+ software platform,the dynamic grid technology was used to simulate the sloshing motion of the tank under forced excitation,and compared it with the public test results to verify the accuracy of the numerical method;and discussed the influence of the filling speed rate on the pressure of the bulkhead.As a result,it was found that the filling can suppress the violent degree of the sloshing of the liquid surface in the tank,and the higher the filling speed,the more obvious the suppress effect.(2)Designed and completed the model test of the coupling effect of liquid sloshing and tank motion during the filling process,and studied the influence of the model under two states of fixed and rolling free attenuation motion in still water,when under different working conditions(tank loading rate and filling speed),on the bulkhead pressure and tank motion response.According to the bulkhead pressure curve of the tank in fixed state and roll attenuation motion in still water,it can be found that filling has no obvious effect on the liquid level without violent movement;when the tank is conducting the roll attenuation motion in still water,the free liquid surface is "solidified",then the roll decay speed and rolling frequency are mainly related to the gravity of the tank.The lower the gravity,the faster the roll decay and the higher the roll frequency;when the tank is undergoing roll attenuation motion under filling,filling has a slight influence on the tank roll motion with low liquid loading rate but has obvious effect on tank roll motion with high liquid loading rate.The higher the filling rate,the smaller the tank roll frequency,and the filling will speed up the decay rate of the test model’s roll motion.(3)Through numerical simulation,the coupling effect of liquid sloshing and tank motion under the working condition of 50% loading rate was simulated and analyzed,and the test results were compared to verify the accuracy of the numerical calculation method.On this basis,the influence of different initial roll angles on the tank roll attenuation motion in still water is further discussed by numerical simulation.The results show that the greater the initial heel angle,the greater the roll frequency of the tank’s free decay.The filling can reduce the roll frequency;and the larger the initial heel angle,the faster the tank’s free decay speed.When the heel angle is small,the stilling affects the decay process,and when the heel angle is large,the effect of filling on the decay speed trend is not obvious.