Investigations of Rudder-propeller Clearance on Thrust Performance and Flow Field in Vicinity of Propeller

The presence of the propeller affects the hydrodynamics of the rudder in the same way that the ship’s hull interferes with the function of the propeller behind and vice versa. Therefore, the arrangement of the propeller and rudder is very important in determining the overall ship propulsion performance. This paper presents a numerical analysis of the KCS propulsion system at various longitudinal clearances with respect to the rudder position. The analysis was performed in a fulship configuration using the KCS hull, propeller, and rudder. The propeller clearance was varied on the basis of the existing KCS design, design adjustments, and recommendations from DNV by 0.1240.129, and 0.100 D. Propeller performance was analysed based on individual variations, interactions between the propeller and rudder, and variations in the number of meshes of 0.5, 1.0, and 1.5 milThe flow distribution around the propeller and the pressure distribution of the rudder inflow onto the rudder surface are also discussed. Numerical examination revealed that DNV’s recommended clearance of 0.100 D provided the best results and improved KCS propulsion performance compared with the existing design. The mesh sensitivity analysis revealed that the recommended clearance showed excellent performance in all mesh variations. In response to these findings, modification othe KCS propeller clearance following DNV recommendations would be beneficial to improve overalship performance.