CFD Prediction Of Navigation Performance Of Surface Ships

Using CFD to predict the navigational performance of surface ships,it can predict and evaluate the various ship design schemes,attachment arrangement schemes and hydrodynamic performance of thruster design in the design stage,realize the ship design technology and approach based on simulation,and reduce the development cost and cycle of new ship types.In this thesis,self-developed CFD software is used to study the navigation performance prediction technology of surface ships based on viscous flow integrated sixdegree-of-freedom motion and overlapping grid technology.Taking the international standard model DTMB5415 series and KCS model as the research object,the numerical analysis models of rapidity,maneuverability and seakeeping of surface warships are established.The characteristics of resistance,propulsion,free self-navigation,rotary motion,Zigzag motion and wave motion of the DTMB5415 series and KCS model are analyzed and studied,and the uncertainty of numerical prediction results is analyzed,assessed and verified.At the same time,according to the typical navigation conditions,the pool experimental study is carried out,and the numerical prediction analysis is compared and verified with the relevant test results.(1)Taking the international standard model DTMB5415 series as the research object,based on the viscous flow integrated 6-DOF motion module and the structured overlapping grid technology,the CFD prediction and analysis of the flow field and hydrodynamic performance of the self-propelled model of a typical surface ship were carried out.The uncertainty of the simulation results was analyzed.By analyzing the detailed calculation results of flow field,such as surface pressure distribution,concomitant flow field information,free liquid surface waveform and the evolution process of vorticity field,the prediction accuracy of flow field and hydrodynamic performance of the self-propelled surface ship model was analyzed and verified by experiments.The uncertainty analysis of relevant test results was carried out and compared with the simulation results.Taking standard ship model KCS as the research,the free navigation numerical simulation of KCS was completed based on different propeller modules,and the differences between the test and the self-developed solver discrete propeller modules were compared.The accuracy and reliability of the improved volumetric force method are verified by comparing the details of the flow field,such as the propeller’s self-navigation rotation speed,propeller flow field characteristics and hull free liquid surface waveform.(2)Based on the numerical simulation of 5415 series free self-navigation of standard ship model,based on the overlapping grid technology and PID control technology,the numerical simulation of the rotation and Z-shape maneuverability of 5415 m free self-navigation in still water is carried out,and the comparison and analysis are made with the test data.(3)Using self-developed CFD software,the numerical wave making method of viscous flow is studied.The uncertainty of numerical wave making is analyzed,and the accuracy and reliability of the viscous flow numerical wave making method based on self-developed CFD software are verified by comparing and analyzing the results with the theoretical solutions.Numerical wave tank for regular wave and irregular long peak wave are developed and established,which lays a foundation for numerical simulation analysis and research of seakeeping of surface ships.(4)Taking the motion of standard ship model 5415 series in waves as the object,the numerical prediction research on the motion characteristics and rotation of surface ship model in waves is carried out,and the precision and accuracy of the numerical simulation results are verified by comparing the relevant test results.(5)Taking the motion of standard ship model KCS in regular wave as the object,the numerical simulation of parameter roll in regular wave of KCS is carried out.The uncertainty of numerical simulation results is analyzed and studied,and compared with the experimental results.The results show that the self-developed CFD software can accurately predict the occurrence and motion characteristics of parameterized roll events of surface ships,which lays a foundation for the establishment of the second-generation stability prediction method based on viscosity in the future.Through the numerical simulation analysis and research on the navigation performance of surface ships based on self-developed CFD software,the modeling methods,uncertainties and prediction accuracy of the rapidity,maneuverability and seakeeping of surface ships predicted by self-developed CFD software are compared and verified.The results show that the self-developed CFD software can accurately predict the navigation performance of surface ships,which lays a technical foundation for the formation of selfdeveloped CFD software for the navigation performance of surface ships.