CFD Numerical Analysis On Hydrodynamic Performance Of Trimaran Planing Hull Tunnels

Trimaran planing hull is a new kind of high performance ship which has both the advantage of trimaran and planing hull.It has excellent high speed ability and stability.Trimaran planing hull has two tunnels beside the mainbody which provide the aerodynamic lift during high speed and they also affect the hydrodynamic performance of trimaran planing hull.This paper use CFD method to analyze the effect of different form of tunnels on hydrodynamic and aerodynamic performance of trimaran planing hull.Based on the data from model experiment,this paper has worked out a numerical simulation program which fits the speed Fr_?(28)2.6~6.8.The thickness of boundary layer and the grid form in region has been taken into consideration and this paper has researched how the boundary layer thickness and grid form affect the accuracy of CFD simulations.This paper has set four key tunnel parameters which include the height of tunnels,the width of tunnels,the length of top straight segment of tunnels,the length of side body.19different models have been designed which has only one variable key tunnel parameter.The speed of simulations all varied from Fr_?(28)2.6~6.8.The analysis on hydrodynamic and aerodynamic of trimaran planing hull has been made after all the simulations finished.This paper also used the stepwise regression method to conclude a function formula between the resistance and the key tunnel parameters.After the CFD simulations on different forms of trimaran planing hull,a new method which aimed at reducing the resistance has been put out on the trimaran planing hull.Jet air in tunnels has been proved to be an effective way to reduce the resistance in foreign research,this paper used two different jet positions and two jet methods and each one has three jet speed in simulations.Contrast analysis of hydrodynamic and aerodynamic performance has been made between original model and jet models.