ON THE USE OF PRESSURE DISTRIBUTIONS TO MODEL THE HYDRODYNAMICS OF AIR-CUSHION VEHICLES AND SURFACE-EFFECT SHIPS

This paper surveys the research conducted on the hydrodynamics of trav eling pressure distributions in the period since the first air-cushion -supported marine vehicles appeared. Most of this work has been based on the approximations of potential-flow theory with linearized free-su rface conditions, because the level of pressures in these craft is suf ficiently low to make these assumptions valid. The specific topics con sidered include the influence of the planform shape as well as the nat ure of the pressure fall-off at the edges of the distribution. The eff ects of canal sides and bottom (as in a towing tank) can also be inclu ded. Additionally, arbitrary motion of the pressure (representing a ma neuvering vehicle) and fluctuating pressure (modeling the motions in w aves) can be studied by the methods detailed here. A number of experim ents have also been conducted. These show that there are many instance s where the theory can be used to predict the resistance and other imp ortant quantities with useful accuracy.