Planing Hulls – Ship Motion

Flow around the hulls of ships is an important focus for naval architects. Many aspects of the flow past the hull need to be examined, including the resistance (drag), stern boundary layer, streamwise vortices, and velocity field at the propeller plane. FLOW-3D‘s Moving Objects Model allows naval architects to model the behavior of hulls in displacement, semi planing or planing regimes, as well as the transients of hulls accelerating onto the plane. FLOW-3D‘s natural strengths modeling free surfaces allows engineers to accurately predict the pressure field acting on a hull even in large amplitude wave or high speed regimes, where slamming forces too can be evaluated.

The hydro-dynamic response of a planing hull is analyzed in three distinct regimes that are demonstrated in this series of simulations. The first simulation shows the ‘rise to the plane’ stage during which the motor yacht accelerates until the hydrodynamic forcing is sufficient to effectively lift the yacht above the water. The second simulation shows the yacht cruising on flat water at 40 knots, and the third simulation shows the response of yacht at high speeds with an incoming wave field.