CFD Helping Yacht Design for America’s Cup

boling2000

The America's Cup, dating from 1851, is the oldest trophy in international sport and is considered to be yacht racing's Holy Grail. With such importance based on the design, CFD (Computational Fluid Dynamics) has become crucial in the production of a winning yacht.
In the year 2000, a German challenger started to work towards a future challenge called Pinta Racing. An international team of experts for hull form design, sailing aerodynamics, and further technical resources were brought together to support an outstanding crew of internationally renowned sailors to challenge the cup holder. The independent consulting company, Hamburg Ship Model Basin (HSVA) was asked to join the Pinta Racing’s expert team and perform the hydrodynamic assessment of the new ship hull. The main activities of HSVA comprised CFD computations and natural experimental tests in their large towing tank. The CFD analysis was based on potential flow results using the CFD code Comet from the CD adapco Group.

  



Validation experiments were performed in the large towing tank. In addition to this, by using CFD it was possible to model the rudder, keel, bulb and winglets, and the turbulence and free-surface effects. It was found that computations for the different designs always predicted the same trends as found in the validation experiments. The CFD simulations thus proved their ability to account for relative changes in resistance when design or sailing conditions are changed, almost as reliably as experiments. This allows a reduction in the number of experiments needed for validation purposes, since these can be limited to the optimum design found by simulation.
The results demonstrated the suitability of the CD adapco Group’s Comet solver for the analysis of flow around yachts under sailing conditions as a complement to experimental testing. In the early design phases, CFD solvers are needed to accurately account for the effects of turbulence and high free-surface deformation, including breaking waves. In future, coupled analysis of wind flow around sails and water flow around hull and appendages in sea waves, will be performed to model the interaction of all yacht components affecting its performance.
“Although the team were not ready for the America's Cup challenge in 2002, the results obtained in the CFD and experimental investigations provide a valuable basis for the future. With the cup being back in Europe for the first time since 1851, expectations are high and the Pinta Racing team is hoping to establish a new challenge for the next round, most likely in 2007. We all hope that at that time, it will be possible to demonstrate the usefulness of CFD results in race conditions.” Bettar el Moctar, HSVA