COMPUTING SHIP WAVE RESISTANCE FROM WAVE AMPLITUDE WITH A NONLOCAL ABSORBING BOUNDARY-CONDITION

A method for computing ship wave resistance from a momentum flux balan ce is presented. It is based on computing the momentum flux carried by the gravity waves that exit the computational domain through the outl et plane. It can be shown that this method ensures a non-negative wave -resistance, in contrast with straightforward integration of the norma l pressure forces. However, this calculation should be performed on a transverse plane located far behind the ship. Traditional Dawson-like methods add a numerical viscosity that dampens the wave pattern so tha t some amount of momentum flux is lost, and resulting in an error in t he momentum balance. The flow field is computed, then, with a centred scheme with absorbing boundary conditions. (C) 1998 John Wiley & Sons, Ltd.