Example of CFD calculation for Wide-Light project Recent projects

‘Wide-Light’ reference calculations MARIN recently conducted calculations to compare them with the published set of experimental tests, the “Wide-Light project”. The Wide-Light design is meant to describe the contemporary design of high performance sailboats. The project1

, conducted by the

Sailing Yacht Research Foundation (SYRF), provided insight into the accuracy of existing modelling methods in predicting the performance of Wide-Light designs.

Team AkzoNobel in the Volvo Ocean Race MARIN collaborated with Volvo Ocean Race competitor Team AkzoNobel to assess the performance of their yacht in a large variety of real operational conditions. In particular, this work gave insight into the performance in waves, which should lead to better routing decisions. The combination of CFD calculations and model testing, with a unique dedicated set-up, all contributed to the success of the project.

Fast vs. accurate, low-fidelity vs. high-fidelity? Nowadays computational times have become less of a limit thanks to the availability of fast hardware and faster tools to prepare the calculations themselves.

The design challenges can be studied using a series of (small), systematic variations. For instance, when studying wide versus narrow, a series of calculations can be planned with hulls that are scaled in width and height. With parametric variations, genetic algorithms can also be used to find

Example of CFD analysis to check paths of trailing vortices

Volume distribution and profile outline over vessel length

the optimum design point. Depending on the exact design challenge that is studied, this will require a Velocity Prediction Program with aerodynamic modelling as part of the loop.

Depending on how these studies fit into the design phase of the yacht, it still has to be decided how quickly the results must be available (required time for the calculations) and the necessary accuracy level of the results. High accuracy will require high- fidelity calculations, resulting in longer

calculation times. During a design exploration, the accuracy may be decreased if at least the trends are good, whereas the best accuracy is required for the development of a final speed prediction. At MARIN both approaches are possible by combining non-linear panel codes with high-fidelity CFD codes.

1 Claughton, A.R., SYRF Wide Light Project, 2015. Sailing Yacht Research Foundation.

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