Research On The Resistance And Seakeeping Performance Of Medium-high Speed Vessel Based On CFD

With the rapid development of science and technology,it’s becoming more and more reliable and economic to study the ship’s hydrodynamic performance using the numerical simulation method.By now,the numerical method has become an important method in ship design and researching field.As a supplementary approach of the traditional model test,it enjoys so many advantages: it is low-cost,environmental-friendly,flexible and can shorten the ship design cycle significantly.We can work much more efficiently by combining the numerical and experimental methods together.In this paper,the author mainly focused on studying the ship resistance performance in calm water and the seakeeping performance in the waves,we discussed the application of ship numerical tank method in these two areas.We concentrated on studying and solving the key problems in the process.The main work of this paper can be summarized as follows:Firstly,a medium-high speed inshore patrol vessel was taken as the research object.The towing tank experiments were carried out to study the resistance performance.In the experiments,we studied the effect of adding stern flap and the effect of changing the position of the center of gravity in terms of resistance reduction.We used the Ansys Fluent software which is based on the Finite Volume Method as a researching tool.A method which can be used to predict the ship resistance was achieved.Considering the fact that if the ship is travelling at relatively high speeds,the navigation attitude would change significantly,we used a static-equilibrium-based method to estimate and modify the sinkage and trim motion.By adopting this method,the predicted resistance results agreed well with the experimental results eventually.Secondly,the author applied the prediction method to optimize the ship hull form,aiming to decrease the ship resistance when the ship is travelling at designed speed in still water.In this process,we focused on studying the effect of different positions of buoyant center;we determined the best longitudinal position considering the resistance performance at designed speed.In the end,we studied the resistance performance of the new optimized ship hull using the numerical simulation tool.Results showed that the.resistance can be decreased.Lastly,we used the ANSYS AQWA software to study the seakeeping performance of a deep-vee ship.Three methods to correct roll damping had been discussed and applied.Compare with the experimental results,the simulation results roughly agree well with the experimental results.From the work done in this thesis,we can see that it is effective to study the ship resistance performance and seakeeping performance based on CFD methods.And the CFD methods is engineering worthy.