An Investigation of Hovercraft Wavemaking

Abstract

The main purpose of the investigation has been to clarify the definition of hovercraft wavemaking resistance and to improve understanding of the physical mechanism. The most literal definition of wave resistance as the force which makes the waves is proposed and its practical and theoretical implications are considered. Various interim accounts of this work have already been written, but the time now seems appropriate to assemble and review the overall picture which is emerging.The pattern of forces on a hovercraft over water is often difficult to analyse because of the complicated interaction between wavemaking, jet air momentum, cushion pressure, wetting and other effects. It is important, however, in making power predictions that the physical interpretation and corresponding scaling laws of the various forces should be understood. A significant feature of the present approach is that a positive and unambiguous basis for identifying the wavemaking force is offered and compared with theoretical predictions. This force, according to the definition proposed, is assured a proper compliance with the physical laws which govern the waves generated and the corresponding scaling and interference effects, which are predicted by theory.