Study On Influence Of Sliding Channel On Wave Absorbing Performance In Still Water And Seakeping Performance Of The M-craft

The M-type craft is a new type of high-performance planing craft that utilizes static buoyancy,hydrodynamic lift,and air static lift during the navigation phase.Different from other composited ships,the M-type craft has a uniquely shaped sliding channel.In the gliding navigation phase（Fr_▽>3）,in addition to the use of hydrodynamic lift,the wave energy generated by the bow is used to generate air static lift which greatly reduces the wave-making resistance.In the practical application,the energy consumption of the first wave making can reduce the impact of the M-type craft and passing ships on both sides of the riverway in the course of navigation,and help the M-type craft break through the speed limit of the channel.The water and air will be also compressed and mixed in the sliding channel to wet the surface,thereby reducing the viscosity coefficient of the medium and achieving the effect of drag reduction.At present,the research of the M-type craft mainly depends on the method of model test.In order to analyze the working mechanism of the sliding channel,it is necessary to use numerical method to analyze the hydrodynamic performance of the M-type craft.By using the method of overset grid,the rapidity performance of the M-type craft can be accurately simulated when the speed is up to Fr_▽=5.The influence of the sliding channel parameters on rapidity of the M-type craft is discussed,and the seakeeping performance of the M-type craft in waves can also be captured and analyzed.In this dissertation,based on the CFD method,the commercial software Star-ccm+is used to numerically simulate the speed and wave resistance of the M-type craft.The main research contents of the dissertation include:（1）Numerical simulation of the M-type craft’s is carried out by a series of grid schemes.After comparing with the experiment results and considering the calculation efficiency,the best grid scheme of the M-type craft is obtained;（2）Adopt the validated grid scheme,change the parameters of the sliding channel,and discuss the influence of the channel height,channel width,rigid wall thickness and the longitudinal dimension of the sliding channel on the M-type craft’s hydrodynamic performance.It is concluded that increasing the height,width and the length of straight section of the sliding channel are beneficial to improving the hydrodynamic performance of the M-type craft;（3）Based on the numerical simulation method,this dissertation analyzes the first wave splashing and wave on deck of the M-type craft in the course of navigation,puts forward some suggestions like modify the bow lean degree of main hull and the length of rigid wall,and verifies the reliability of the suggestions by numerical simulation method.Through the change of the model craft,the universality of the improvement suggestions is verified;（4）The numerical wave basin is established and verified to study the seakeeping performance of the M-type craft under different speed waves,zero speed waves and head slant waves.The hydrodynamic performance of the M-type craft in still water and waves is comparatively complete.The research in this dissertation can provide reference for the design of the M-type craft and the analysis of hydrodynamic performance in still water and waves.