| The catamaran planing crafts is a new type of ship that is gradually derived from the design of aerodynamic ships.The unique design of the central channel structure combines aerodynamics and hydrodynamics.No matter the drag reduction effect and seaworthiness are superior to the traditional monocoque,but because of its strong non-linear characteristics during navigation,most of the early studies used real ship model experiments to study the hydrodynamic characteristics.In recent years,with the development of Computational Fluid Dynamics(CFD)of ships has advanced the accuracy of CFD technology in simulating the calculation of ship hydrodynamic characteristics and the state of the flow field around the hull.Based on the star-cmm + platform,this paper uses CFD technology to calculate and analyze the sailing state of the catamaran,and to study its influence on the hull sailing performance by changing the hull parameters and installing hydrofoil wave pressure plates.First of all,this paper takes CAT900 planing craft as the mother ship,uses overlapping grid and moving grid technology to establish a numerical calculation model,performs reasonable grid division and boundary condition settings,and verifies the validity of the calculation results by comparing the calculation results with experimental data.The drag reduction mechanism is studied by calculating the resistance of the catamaran and the surrounding flow field.The dynamic calculation of catamarans with different channel shapes is described from the angles of navigation resistance,trim angle and heave distance and show the sailing performance of ship shapes with different channel shapes.Secondly,by changing the channel parameters such as channel width,channel height,and channel side wall angle,to calculate the influence of each parameter on the navigation performance of the sailing boat such as navigation resistance,navigation attitude and wave-making performance.The research results show that the initial increase of the channel width,height and sidewall angle has a beneficial effect on navigation performance,but after reaching a certain level,the improvement of hull navigation performance is limited,and it may even have a deduction effect.Subsequently,a channel hydrofoil was installed inside the catamaran channel,and the sailing status of the catamaran with different parameters of the hydrofoil was calculated by changing hydrofoil parameters such as different airfoils,installation positions,and angle of attack.Analyze and study the gas-liquid distribution status,flow field velocity distribution and ship bottom dynamic pressure distribution inside the hull channel,and analyze the influence of hydrofoil parameters on seaworthiness during navigation.Finally,install the tail wave plate on the stern of the catamaran,change the parameters of the tail wave plate length and the depression angle,calculate and analyze the movement state of the taxi boat and the surrounding fluid changes when the tail wave plate is installed with different parameters,and study the reduction of the tail wave plate.Resistance mechanism and the effect of improving wave effect. |
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