CFD Analysis of Propeller Tip Vortex Cavitation in Ship Wake Fields Free

TVC on marine propellers in behind-hull conditions is a challenging problem for numerical predictions, because it is deformed in turbulent viscous interactions with hull wake, propeller-induced flows and rudder disturbance. DES is made for cavitating flows on a propeller and a rudder of a military vessel with a 3.5° shaft inclination in non-uniform hull wake. While a cavitation tunnel test shows TVC extending over the rudder, only a short extent of TVC is reproduced in DES on the initial grid. After an adaptive grid refinement based on the Q-criterion, a larger extent of TVC is simulated and the first- and second-order pressure pulses on two points above the propeller are closer to the experimental measurements. The effects of hull wake, propeller-induced flow, rudder disturbance and shaft inclination on TVC are analyzed by looking into the deformation of the helical trajectory identified by a Q-criterion iso-surface.