| With the implementation of the plan for the rise of Central China,the economy of the central region has entered a stage of rapid development,and the volume of cargo in the Yangtze River has increased year by year.In recent years,the construction of the Jinghan Waterway to completely solve the “middle obstruction” of the Jingjiang section in the middle Yangtze has been put on the agenda.In this context,this paper uses CFD software to simulate the scene when the ship sailing in artificial waterway,and discusses the matching relationship between the section size of large artificial waterway and the navigation performance of the ship.In order to determine the channel section size matching the main ship type sailing in the Yangtze River in the future,the simulation considers the bottom widths,water depths and slope ratios of the bank.Considering that the free surface width will vary with the above parameters,the lateral position of the ship in the channel section is determined by the ship-bank distance ratio on both sides.It shows that at the same the ratio of ship-bank distance on both sides,the ship's resistance and vertical suction decrease with the increase of the channel bottom width and water depth,this trend is gradually slowed down,while the influence of the slope is less obvious.And the effect on reducing the resistance of the ship is not signal when the ratio between the width of the channel and the ship breadth is greater than 4.55,and when the water depth draught ratio is less than 2,increasing the water depth has a significant effect on reducing the pressure drag.Then the paper continue to discuss the hydrodynamic forces acting on the hull and the bank effect about the Froude number when sailing in different lateral positions of the channel section,as well as the characteristics of the wave amplitude and the change of the pressure on the bank.The results show that with the increase of Froude number the coefficient of frictional resistance of the ship firstly decreases and then increases,while the coefficient of pressure drag and the coefficient of vertical suction maintain monotonous increase,and the smaller the ship-to-shore distance,the greater the drag coefficient.The turning moment and the lateral suction of the bank effect generally increase with the increase of the Froude number and the decrease of the ship-bank distance.However,due to the influence of the ship and the near-shore flow field,the non-monotonic phenomenon appears.The amplitude of the wave and pressure change values on the bank increase with the increase of the speed and the decrease of the shipbank distance,and the smaller the ship-bank distance,the greater the trend of this change.Considering the artificial waterway is a restricted channel,the floating state of the ship will change greatly.In order to get the ship's sinkage to ensure the safety of the ship.In this paper,the dynamic grid technique is used to simulate the average sinkage of the ship at different speeds.And compared with the results calculated by the semitheoretical formula based on mass conservation and Bernoulli equation,the ship sinkage calculated by the static balance calculation according to the vertical suction of the constrained model.The results show that the results of free model and constrained model are close at low speed,and the difference is obvious after the speed increases,while the semi-theoretical formula is always smaller compared to the result of the free model.Part of the simulation has been verified by model test to ensure the reliability of the calculation. |
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