Numerical study on the gap flow of a semi-spade rudder to reduce gap cavitation

The flow around the gap of a semi-spade rudder was simulated as part of an effort to minimize gap cavitation. Simulations were performed for various devices aimed at controlling the gap flow in two-dimensional and three-dimensional domains using the Reynolds-averaged Navier–Stokes equations. A significant difference in the pressure field near the gap in two- and three-dimensional computations was found. In particular, the pressure field of the gap, where the local flow is dominant, and that of the main flow from the propeller were compared. Finally, a remedy for the gap cavitation that occurs between the horn and the rudder was introduced.