Research On Prediction Method Of Trimaran Resistance And Diagram Based On Series Model Test

With the rapid development of modern computer technology,using computer to solve the partial differential equation has become a popular trend,and all sorts of commercial CFD software also get rapid development in this situation.In the research field of forecasting ship resistance performance,CFD method can handle with resistance calculation of free surface flow,or the method of double model can calculate viscous resistance.Appliance of CFD method,on the one hand,is very convenient and efficient to get resistance calculation results,on the other hand,can get timely flow field image that makes the complex flow field information more detailed and specific.In a word,predicting ship resistance performance with CFD method has become another kind of simple,effective method and means of a traditional resistance model test.Its degree of freedom is unlimited when ship sailing.The navigation attitude of ship(especially for high-speed ship)is greatly affected by the restriction of freedom degree.In the CFD simulation process of ship motion,generally the method of limited freedom is adopted to simplifying the problem.This influences the accuracy of resistance prediction to some extent.For the high-speed trimaran,the navigation attitude will generally change with the increase of Froude number(Fr).CFD prediction resistance method of restrict freedom is based on floating design,and uses navigation attitude of fixed ship,so results in certain error in calculation result.In this paper,a bow trimaran model as the research object,according to two kinds of model of freedom and constraint on CFD numerical simulation,gets the differences of resistance and flow field information,and the test of the verification of the resistance model.For determining that method of trimaran form factor 1 + K is a controversial issue.In this paper,based on the CFD model,calculates and determines the method of catamaran and trimaran's from factor.Firstly a monomer bulk carrier is calculated by CFD stack mold method in different speeds of hull shape factor 1 + K,the feasibility validation of mono-hull ship shape factor 1 + K method is based on CFD model.On this basis,the method is applied to determining the trimaran shape factor 1 + K,and relevant conclusions are obtained.Finally,this paper is on the research of a high-speed trimaran model,series resistancemodel tests are designed,with the side body layout(axial and lateral direction layout),the side displacement volume ratio(the ratios between side body and total displacement),vertical location of buoyancy,and aspect ratio of mid-body as parameters,draws the residual resistance coefficient curve associated with the above variables and makes a brief analysis,generates the ship resistance charts(residuary resistance coefficients).