The Research Of Resistance And Seakeeping Of Planning Craft With Fixed Hydrofoil

With the rapid development of society,the exploring extent of the marine is increasingly large,people's requirement of the seaworthiness of ship is more and more high.As the first application high-performance ship,Planning craft has good speediness.But its seakeeping in the wave is bad.Adding the appendage on hull is available to improve the planning craft seakeeping.This paper researched the influence of fixed hydrofoil for the resistance and seakeeping of planning craft.Firstly,the numerical method of hydrodynamic performance of planning craft was studied.The influence of grid division and time step for the numerical results of the resistance was analyzed by calculating the resistance of a prismatic type boat model,and obtaining a efficient and well-precision meshing way and the time step formula.And then,the straight movement of a monomer glider model in calm was simulated by using domain moving grid technique to simulate 6DOF.using overlapping grid to deal with the grid moving problems and using orthogonal cutting grid to adapt to the complex surface.Following,multiple rule waves and the motion of monomer glider in heading rule wave were simulated by using VOF Wave in the software.By comparing with experimental or theoretical value,it proved that the numerical method could accurately calculate the hydrodynamic performance of monomer glider.Then,the influence of fixed hydrofoil for the resistance and seakeeping of planning craft was analyzed when the hydrofoil was at different longitudinal sites,had different main wing areas,had different heights of main wing from the bottom of boat and was fixed with different main wing angle of attack.Calculation results showed that adding suitable fixed hydrofioil could obviously improve seakeeping of planning craft.The effect of hydrofoil with main wing with suitable negative angle of attack was best,it made boat gain greater lift through enlarging the trim.The drag reduction effect in calm water was better also.At last,under different speeds,the resistance and sailing attitude of a planning craft with stem fixed hydrofoil and the origin boat in calm water were calculated and compared in detail.And under the heading rule wave condition,the sailing resistance and resistance increase in wave?pitching and heaving motion and center of gravity and stem vertical acceleration in different speed?different wavelength and wave height were compared and analyzed in detail.Results showed that adding suitable fixed hydrofoil could obviously decrease the calm water resistance of planning craft in middle and some high speed and obviously improve seakeeping.But when the speed was very high,the calm water resistance and sailing resistance in wave increased severely.