YACHT97: A fully viscous nonlinear free-surface analysis tool for IACC yacht design

A novel free-surface computer program, used to calculate the viscous flow field about a full configuration sailing yacht, is presented. The numerical techniques incorporated into the computer program - YACHT97 - facilitate accura1e quantification of the residuary and the frictional drag components through the use of a "moving" computational grid which conforms to the exact wetted surface area of the hull. Use of a full field approach, whereby the entire flow domain is discretized, permits the simulation of the boundary layer and wavemaking interaction as well as the onset of vortex structures which appear downstream of lift producing appendages. A recently implemented free-surface discretization permits the bow wave evolution to proceed to the near-breaking point. Computed results include comparisons between the inviscid and viscous flowfields about a bare-hull configuration and a full configuration with keel and rudder appendages.