CFD for twin gondola aft ship design

This paper shows a test case in the optimization for a twingondola ship. In optimizing ships, one can optimize for minimal resistance or for minimal power. For twin-gondola this choice is of great importance, due to the asymmetric nature of the flow coming into the propeller. We first show the optimization of a twin-gondola ship for resistance only, where the decrease in resistance is found to be 1.5%. When including the propeller, using RaNS-BEM coupling, a large difference is found between inward and outward rotating propeller. The ship with the largest resistance, requires the least power if the propeller turns in the right direction. We show that RaNSBEM coupling could be an efficient method of taking the propeller rotation direction into account in an optimization process. The results are also compared to a model test of the same ship, showing the same trend.