Investigation on a two-part underwater manoeuvrable towed system

A hydrodynamic model of a two-part underwater manoeuvrable towed system is proposed in which a depressor is equipped with active horizontal and vertic al control surfaces, and a towed vehicle is attached to the lower end of a primary cable. In such a system the towed vehicle can be manoeuvred in both vertical and horizontal planes when it is towed at a certain velocity and the coupling effect of excitations at the upper end of the primary cable an d disturbances of control manipulations to the rowed vehicle can be reduced . In the model the hydrodynamic behavior of an underwater vehicle is descri bed by the six-degrees-of-freedom equations of motion for submarine simulat ions, The added masses of an underwater vehicle are obtained from the three -dimensional potential theory. The control surface forces of the vehicle ar e determined by the wing theory. The results indicate that with relative si mple control measures a two-part underwater manoeuvrable towed system enabl es the towed vehicle to travel in a wide range with a stable attitude. The method in this model gives an effective numerical approach fur determining hydrodynamic characteristics of an underwater vehicle especially when littl e or no experimental data are available or when costs prohibit doing experi ments for determining these data. (C) 2001 Published by Elsevier Science Lt d.