Numerical Study Of Hydrodynamic Forces On A Hull With Propeller And Rudder In Maneuvering Motion

The maneuverability of ship is closely related to the safety of ship navigation,so it is very important to accurately predict the maneuverability of ship.The hydrodynamic derivative of the ship can be obtained by the maneuvering motion test of the captive ship model,then the maneuverability of the ship can be predicted.With the development of CFD（Computational Fluid Dynamics）technology,some traditional physical experiments can be replaced by CFD method.Recently,the research on the maneuvering motion test of the captive ship model has been relatively mature,however,in most cases the influence of the propeller is not considered.But in fact,the influence of propeller on hydrodynamic forces of a ship in maneuvering motion cannot be ignored.In view of the above problems,numerical simulation of the maneuvering motion test of the captive ship model for the hull-rudder system and the hull-propeller-rudder system of KVLCC2 is carried out in this paper,and the influence of propeller on hydrodynamic forces of the maneuvering motion test of the captive ship model is analyzed,the main work includes:Firstly,the resistance test of KVLCC2 and the open water performance test of KP458 propeller are numerically simulated respectively,and the result is compared with the test results;the method based on real propeller（sliding mesh method）and the body force method（H-O body force model）is used to simulate its self-propelled performance,and the calculation results of the two methods are compared,Then,numerical simulation of the maneuvering motion of the captive ship model for the hull-rudder system and the hull-propeller-rudder system of KVLCC2 is carried out in unrestricted waters,the calculated results agree well with the experimental results,the calculation results show that the propeller only affects the pressure distribution on the stern and rudder surface and the flow field distribution around the stern,but has little effect on other positions;for different maneuvering motion of the captive ship model,the influence of propeller on ship maneuvering hydrodynamic forces is different;comparing the method based on real propeller and the body force method in studying the hydrodynamic forces of the hull-propeller-rudder system,in general,the pressure distribution on the stern and rudder surface and the flow field distribution calculated by the two methods is consistent,the details of the flow field are different only in the range of the propeller disk,but not in other areas.Finally,numerical simulation of the oblique towing test and the rudder angle test for the hull-rudder system and the hull-propeller-rudder system of KVLCC2 is carried out in restricted waters,the body force method is used to deal with the rotating propeller.The calculation results show that,compared with deep water,the velocity of the water around the hull increases and the velocity around the rudder decreases in the shallow water,so the hydrodynamic forces of the hull increases and the rudder efficiency decreases;the propeller will weaken the effect of shallow water on the rudder efficiency,the difference of rudder efficiency under different water depths is much smaller than that without propeller;compared with deep water,propeller has less influence on ship hydrodynamic performance in shallow water;the influence of the bank wall on the rudder efficiency is small,and its main influence is the hydrodynamic forces of the hull.