Coupling Analysis Of Tank Sloshing And Hull Motion Of Deep Sea Aquaculture Ship

The construction of deep sea aquaculture ship is a requirement of China’s development strategy of maritime power,which is also beneficial to the development of fishery production mode and the improvement of the quality of aquatic products.However,the huge amount of aquaculture water may pose challenges to the safety of the aquaculture ship.In this paper,the ship hydrodynamic coefficient is calculated based on SESAM software,the ship motion is predicted by the impulse-response function method,and the tank sloshing is numerically simulated by FLUENT software.The coupling equation of tank sloshing and hull motion is numerically solved.The main work of this article is as follows:In order to verify the effectiveness of the CFD commercial software FLUENT in the numerical simulation of tank sloshing,the experiments of the liquid carrier sloshing at various frequencies in the horizontal direction was numerically simulated and the results were compared with the experimental results in the reference literature.By comparing horizontal wall pressure from the numerical simulation with the results obtained in the experiments,it is found that the numerical simulation results agree well with the experimental results in the low frequency domain;but when the excitation frequency goes high,the free surface of the liquid deforms significantly,and the numerical simulation results,which can describe the trend of wall horizontal pressure with frequency,can hardly predict the specific values.Since the sloshing frequency of the aquaculture ship is within the frequency range where FLUENT can accurately simulate,it is feasible to simulate the sloshing force of the aquaculture tanks by FLUENT numerically.In order to verify the effectiveness of the method for discretely solving the coupled equations of tank sloshing and hull motion,numerical simulations were performed for the free-rolling experiments of the ship model at different liquid loading rates.In order to reduce the calculation scale,4 times the sloshing force of one pair of regular tanks is used to replace the sloshing force of four pairs of regular tanks in identical shape.The rolling angle obtained by numerical simulation is in good agreement with the rolling angle obtained by the experiments,which validates the effectiveness of the response-impulse function method for hull motion prediction and the validity of the numerical method used in this paper.Finally,numerical simulations of the roll and heave motion response of the aquaculture ship under the excitation of transverse regular waves of different frequencies were performed,and the roll and heave amplitude response operator（RAO）was obtained.By comparing and analysing the hull motion response under sloshing and solidified water conditions,it is found that the sloshing force plays a role in promoting or inhibiting hull motion under different wave frequencies.Further comparison and analysis of sloshing force and wave force founds that when the movement is stable,if the sloshing force phase is close to the wave force phase,the sloshing force will promote the hull movement under such wave frequency;on the contrary,the tank sloshing force will inhibit the hull movement.The comparative analysis of the rolling RAO obtained with or without sloshing force founds that the sloshing force increases the amplitude of rolling RAO by 43%,and the wave frequency corresponding to the maximum amplitude also decreases.The results shows that the sloshing phenomenon will promote the rolling motion under certain sea...