In the never ending quest for speed, foiling is considered a holy grail in many design classes. The most recent America’s Cup showed spectacular sail racing on foils. With the yearly Dong Energy solar challenge boasts several vessels obtain tremendous advantages by rising to their foils and taking the lead. These high tech racers are only powered by solar energy and aim for the most efficient use of the available power.
Van Oossanen Naval Architects simulated the transition of a hydro foiling solarboat from displacement mode to fully foiling mode at a targeted ride height. To reach and maintain this ride height the pitch of all foils was controlled during the simulation.
The Computational Fluid Dynamics (CFD) package used at Van Oossanen is Fine/Marine by Numeca. The full possibilities of this package were used. The ride height was controlled by using Dynamic Libraries. To allow the pitching of the foils, so called sliding grids were used. To accurately capture the water surface, the grid around the boat was dynamically adapted to the water surface by means of Adaptive Grid Refinement (AGR). These three features of Fine/Marine in general and this simulation in particular, will be explained the three features: Ride height control, sliding grids and water surface capturing. You can see the results in this video.