A hybrid method for computing the bottom pressure field of a planing boat

A hybrid numerical method for computing the pressure field induced on the seafloor by a planing boat is presented in this paper. This method combines a Reynolds Averaged Navier-Stokes (RANS) solution with a linear, potential-flow solution in the far field. A control surface enclosing the boat is introduced. This surface is large enough so that viscous effects are important inside the surface but are negligible outside it. Linear, potential-flow theory is, therefore, applicable in the outer region and is used to derive integral equations for the fluid velocity. Unlike traditional formulations where the velocity potential phi in the fluid domain is given in terms of the boundary values of phi and its normal derivative, the new equations define the fluid velocity directly in terms of the finite-depth Green function and the velocity distribution on the control surface. This difference allows the new equations to easily interface with RANS solution where only fluid velocity and not its potential are calculated. As an example, the new hybrid method is used to obtain the pressure signature of the leisure boat Carolina Skiff.