A Study on the Effectiveness of Active Fin Roll-Stabilizers through Numerical Simulation

The effectiveness of a given fin on the roll motion of a given naval platform over a range of speed, heading, loading conditions are studied. The roll motions of the hull are determined based on both coupled sway-roll-yaw equations and uncoupled roll equations, and it is found that roll predictions can be significantly different from these two sets of equations suggesting a strong coupling between particularly sway and roll. The effect of the active fins given by a generic control equation where the fin angle depends on roll angle, roll velocity as well as roll acceleration is added within the equation of motion to determine the roll with the controls working. Results of the numerically simulated roll over different frequency and speed ranges for different control parameters for the chosen hull show that at higher speeds the roll can be reduced by as much as a factor of 6, while at lower speeds, this factor is somewhat low, of the order of 3.