Accurate capture of rudder-propeller interaction using a coupled blade element momentum-RANS approach

Ship rudders are almost always placed downstream of the propeller so they can take advantage of the increased local velocity due to the presence of the propeller race. The methods discussed in this paper replicate the flow integrated effects of the propeller which generates an accelerated and swirled onset flow onto the rudder. As long as the radial variation in axial and tangential momentum (including hull and rudder interaction effects) generated by the propeller are included, then the influence of the unsteady propeller flow can be removed and ’steady’ calculations performed to evaluate propeller rudder interaction. Three different body force propeller models will be considered and numerical results will be compared with experiments by Molland and Turnock [1, 2, 3], using the modified Wageningen B4.40 propeller and Rudder No.2.