Analysis On The Coupling Effect Of Liquid Sloshing And Tank Motion In The Filling Process In Waves

In wave environments,the process of liquid cargo filling into a tank through pipelines often leads to complex coupling effects among tank motion,liquid sloshing inside the tank,and the filling operation.In this study,based on model experiments and numerical simulation methods,the coupling effects of liquid sloshing and tank motion during tank filling in waves were investigated.The main work and conclusions of this thesis are as follows:(1)A test setup for tank filling in a wave tank was designed and constructed.The tank motion was measured using the angular displacement of the tank model,while the free surface motion inside the tank was captured using a high-speed camera.The sloshing pressure on the tank wall was measured using pressure sensors,enabling experimental measurements of the coupling effects between liquid sloshing and rolling motion of the tank during tank filling in a regular wave environment.(2)Experimental research was conducted to investigate the effects of regular wave height on liquid sloshing and tank motion of a liquid cargo tank at a constant filling velocity.Research has found that for regular waves with a frequency of 1 Hz,when filling to a certain filling rate,the roll response amplitude of liquid sloshing tends to decrease significantly.The higher the wave height,the earlier the time point at which the decrease becomes significant.This is mainly related to the dynamic change in the inherent frequency of sloshing due to the increase in filling rate during filling.In addition,the pressure amplitude at the filling pipe mouth also increases with higher wave heights.(3)Experimental research was conducted to investigate the effects of filling velocity on liquid sloshing and tank motion of a liquid cargo tank at a constant filling velocity.The study indicates that a higher filling velocity leads to the liquid cargo tank being more inclined to maintain its own motion state,with more difficult change of motion amplitude,exhibiting a greater damping effect as reflected by the calculated relative damping coefficient from the test data.Moreover,with higher filling velocity,the peak values of pressure and wave height occur later,indicating a more pronounced lagging phenomenon.During filling,the initial impact has a suppressing effect on liquid sloshing,and the higher the filling velocity,the more prominent the suppression of liquid sloshing by the initial impact.(4)Numerical simulations were performed using the experimental model to study the liquid sloshing during forced roll motion of a liquid cargo tank during filling process.The motion of the free surface of the liquid inside the tank,the time history of wave height at measurement points,and the time history of wall pressure were calculated.Pressure spectral analysis was also conducted to identify the various excitation frequencies contained in the liquid sloshing and their contributions to the tank motion.The analysis revealed that with higher filling velocity,the time point at which the liquid sloshing response reaches the same magnitude is delayed,indicating a greater lagging effect,which can be represented by a linear equation with a single variable.(5)Based on the numerical simulation of forced roll motion and filling process of the liquid cargo tank,numerical simulations of wave-induced filling of the tank were conducted in a numerical wave tank.The simulation results showed good agreement with the experimental data,confirming the feasibility and effectiveness of the numerical method established in this study.