IMPACT OF RUDDER GEOMETRY ON THE WAKE EVOLUTIONS OF PROPELLER-RUDDER INTERACTION

The evolutions of propeller wake can be impacted by interaction between the propeller and rudder which results in turbulence enhancement in the propeller wake. The turbulence in the propeller wake worsens vibrations and noise on vessels. The intensive research aimed on the wake evolution in the propeller-rudder interaction brings sights on the control of propeller wake and relief of vibrations and noises. Hence, the rudders with different chord and profile are employed to investigate the impact of rudder geometry on the evolutions of propeller wake. Large Eddy simulation method is used to simulate the turbulence in the flow field. The propeller vortices obtained with different rudder chords and profiles are compared in present study. The impact of trapezoidal rudder on the propeller wake evolution are studied based on the research aimed on the impact of rudder chords and profiles on the propeller wake. The distributions of turbulence kinetic energy in the interaction between the trapezoidal rudder and propeller are also researched in present study. Results show that both of rudder chord and rudder profile can impact the evolutions of propeller wake. Larger chord and thicker profile of the rudder enhance the span-wise displacement of propeller tip vortices. Thinner profile leads to more intense displacement of propeller hub vortex. The vortex trajectory and pressure fluctuations on the rudder surface indicate that trapezoidal rudder enhances the span-wise displacement occurring in anti-direction of rudder tapering. This enhancement takes asymmetry to the propeller wake around the rudder and in the downstream. The turbulences in the propeller wake can be related to the collisions between the propeller vortices and rudder, between the propeller vortices and rudder trail vortex, between the propeller tip vortices and hub vortex. The more intense span-wise displacement of propeller wake induced by trapezoidal rudder brings earlier enhancement on turbulence in the propeller wake.