No abstract

Consequences of roll motions can degrade the effective performance of a ship in a seaway. Roll motion stability becomes more critical when the moving ship encounters beam seas. Such stability is ensured using the actions of extra fins fitted to hull. Roll motion is controlled if the accelerations are high enough to cause any panicky situations for the passengers in the case of a passenger ship. Mission requirements, vessel types, loading conditions, and environmental loads cause the extent of roll and roll accelerations for a ship. In this article, the feasibility of control of roll motion using active fins is discussed. Such fins are better suited for certain types of naval ships. The stability of such vessels becomes critical during fast maneuverings and more critical in the presence of unfavorable weather conditions. Roll motion analysis on the basis of a frigate ship is performed, and proposal to reduce the roll motion using fins is also presented. Lift coefficients corresponding to various angles of attack were obtained using Fluent. Turbulence was modeled using k − ε (two-equation) model and Reynolds stress model. A number of simulations were performed for various sea conditions, and effect of ship speed on the angle of attack required for the fin to stabilize the ship was determined. Case studies were taken up with various sea states and with varying forward speeds of the ship in the beam sea.