CFD Simulation of the Influence of Drift and Heeling on Calm Water Resistance and Added Wave Resistance

Kurzfassung

In order to meet latest and future regulatory requirements with respect to efficiency and emissions, new technologies like wind-assisted propulsion systems (WAPS) will play a vital role for the shipping industry. Although WAPS promise high fuel savings for a broad range of concepts, the application and diffusion of this new technology is still limited. An important reason for that is the high uncertainty with respect to the actual efficiency gains. This uncertainty arises from the complex interactions between WAPS, ship and environmental conditions. These interactions become especially relevant for sail-based technologies which affect the ship’s performance by inflicting substantial drift and heeling. The extent of drift and heeling defines the so called “sailing condition”.

This work focuses on a structured assessment of the sailing condition on the ship’s resistance and other relevant forces. For that, CFD simulations are conducted to determine the influence of drift and heeling on a ship’s calm water resistance and the added wave resistance in regular head waves. The study is applying the commercial finite-volume solver STAR-CCM+ to solve the RANS equations to simulate the performance of the established KVLCC2 tanker geometry for multiple varying drift angles as well as heel angles. For the calm water resistance it is shown that the influence of both drift and heeling is small on the overall resistance, while the yaw moment is increasing under drift and heeling conditions. Moreover, the simulations in waves revealed that the added wave resistance decreases with increasing heel and drift angle in long waves. In short waves instead, added wave resistance is increased by heeling as well as by high drift angles.