Numerical investigation of wave resistance and hydrodynamic responses of an amphibious air-cushion vehicle heading towards shore

This paper presents a numerical investigation of the hydrodynamic performance of an amphibious air-cushion vehicle (ACV) travelling on calm water under different scenarios. An in-house 3D computational fluid dynamics (CFD) solver (Cgles_IBM), which has the capability of capturing the six-degree of freedom movements of a floater, is extended to include the air propulsion process underneath the ACV by using the virtual mass source method. The numerical model is first validated against available experimental data for a simplified rectangular-shaped ACV in a simple lifting motion and a straight forward motion with a constant speed. It is then extended to simulate the full-scale landing scenarios of an ACV with a realistic shape under different forward speeds and landing slopes. It is found that the increase in forward speed and landing slopes can significantly enlarge the heave, pitch, and roll responses. These key parameters may also affect wave resistance characteristics when certain thresholds are exceeded, i.e. the forward velocity approaches the phase speed of gravity waves, or the rate of water depth reduction becomes excessive.