Numerical prediction of ventilated planing flat plates for the design of Air Cavity Ships

In recent years, a great world issue is the respect for the environment. Each researcher, in his competence field, proposes new technologies and new approaches in order to reduce the environmental impact of a product or of an industrial process. In the naval field, the main way in order to reduce the environmental impact of the ship during the navigation is the reduction of the drag resistance and so the reduction of requested power. There are many ways in order to obtain a reduction of drag. This paper investigates, with a preliminary numerical study by means of Computational Fluid Dynamics (CFD), the Air Cavity Ships technology (ACS). A first part of the paper concerns the study of the rising bubble phenomenon inside a water column, in order to choice the better solver settings and understand if the CFD is suitable for this kind of problem. In this phase the main parameters analyzed are: the air critical mass, the rising velocity, the shape and the air circulation inside the bubble. In the second part of the work, a flat plate model with artificial air injection is conducted in order to understand the possible advantages of this application. The principal impacts of this technology are presented in terms of drag coefficient and lift coefficient respect to trim and velocity coefficient. The CFD method could be a suitable and fast method, in the preliminary phase, for the design of the ACS.