In most cases, there is asymmetric flow around a ship induced by the vicinity of banks, which cause pressure differences between port and starboard sides. As a result, her bow is pushed away from the closest bank. This phenomenon on a sailing vessel is known as bank effect. The main goal of this study lies in the discussion of applying FLOW- 3D® computational fluid dynamics (CFD) software to simulate bank effect. Accordingly, this study performs a series of simulations using commercial CFD software and the KRISO 3600 TEU container ship model to examine the effects of the vessel speed and distance to bank on the magnitude and time-based variation of the yaw angle and sway force. The results show that for a given vessel speed, the yaw angle and sway force increase as the distance to bank reduces, while for a given distance between the ship and the bank, the yaw angle and sway force increase with an increasing vessel speed. In addition, it is shown that even when a vessel advances at a very low speed, it experiences a significant bank effect when operating in close vicinity to the bank. Overall, the results presented in this study confirm the feasibility of the CFD modeling has achieved a quite high precision to simulate bank effect without the need for expensive ship trials.
When operating in restricted water and forced to deviate from the center of the channel under vessel meeting and passing conditions, the ship inevitably approaches the bank, and thus an asymmetric flow pattern is produced which generates a pressure difference between the port and starboard sides of the vessel. Generally speaking, a suction effect is induced toward the stern of the vessel, while a cushioning effect is induced at the bow. Thus, as shown in Figure 1, the vessel experiences a positive yaw moment, N b, which pushes the bow toward the center of the channel and a lateral sway force, Y b, which is directed principally toward the nearest bank.
