| As the most important means of transportation in the shipping industry,green ships are the focus of the shipping industry in recent years.It is an effective energy-saving method recognized internationally by adjusting the initial floating state(pitch)of the ship to achieve drag reduction and energy saving.The ship’s trim optimization technology has significant effects and low cost,and is widely recommended by shipping industry researchers and shipowners.At present,most of the research on ship trim optimization is based on the combination of model test and numerical simulation,and most of them are studied under hydrostatic conditions.The operation of ships in the real sea area must be affected by wind and waves,so the ship is studied under wave conditions.The trim optimization is necessary.In this paper,a 300K-VLCC is taken as the main research object.The combination of pool test and CFD numerical simulation is used to study the hydrodynamic performance of ships with different initial pitch angles under hydrostatic conditions and wave conditions.Among them,the towing pool model test mainly measures the ship model resistance,the heave amount and the trim angle,and compares and analyzes the influence of the variation of the trim value on the ship model resistance and the floating state.The discrete method uses the finite volume method,the turbulence model uses RNG,and the free surface is captured by the VOF methodThe towed pool model test mainly conducts hydrostatic resistance test,wave resistance test,measures the hydrodynamic response characteristics of the target ship model under different working conditions,provides verification for ship hydrodynamic simulation,and provides typical working condition data input for rapid simulation module.Provide technical support for forecasting actual ship performance and subsequent theoretical research and ship type optimization.Numerical study on the vertical hull deformation hydraulic performance of VLCC in still water and waves.In the still water,the three conditions of ballast draught,design draught,and full draught are respectively carried out.The value of Fudue is 0.092-0.142,the initial trim change is-0.716°-+0.716°,and the calculation result is carried out by the three-factor method.Conversion.In the numerical study of the trim optimization mechanism,the effects of wet surface area,hull surface pressure and hull wave on the rapidity are analyzed.It is concluded that the change of the initial trim angle has little effect on the frictional resistance.The wave-making resistance is the optimization of the ship’s trim.One of the main factors for increasing resistanceUnder the wave condition,as the wavelength increases,the wave resistance increases first and then decreases.When the VLCC is near λ/L=1,the wave resistance of the ship reaches a peak.When the VLCC ship moves in a regular wave,the increased resistance is mainly concentrated in the front section of the ship.The additional resistance in the rear section is small,while the middle section is basically negligible.Therefore,the data of the two chapters is comprehensive,and the optimal initial pitch angle of the VLCC is 0.179°-0.358°. |
