RANS analysis for hull-propeller-rudder interaction of a commercial ship by using the overset grid scheme

Abstract

The turbulent free surface flow around a self-propelled KRISO 138K LNG Carrier (KLNG) with a rudder is numerically simulated using the finite volume based multi-block RANS code, WAVIS, which is developed at MOERI. WAVIS uses the cell-centered finite volume method for discretization of the governing equations. The free surface is captured with the level-set method and body forces are used to model the effects of a propeller without resolving the detail blade flow. The propeller forces are obtained using an unsteady lifting surface method based on potential theory. By using the overset grid scheme, a rudder can be relatively easily handled in the numerical structured grids and the complex flow phenomena around the stern region due to hull-propeller-rudder interaction can be numerically investigated. The self-propulsion characteristics such as thrust deduction, wake fraction, propeller efficiency, and hull efficiency are compared with the experimental data of the KLNG model ship. Also, the effect of propeller and rudder on the ship wake and wave profiles in the stern region will be discussed and examined.