Design Methods

Analysis of an A-Class catamaran coupling a CFD sail analysis with an analytical velocity prediction program (VPP) tuned against multiphase CFD analysis of the hull.


Sail design is a particularly complex aerodynamic problem. Apart from the capability to accurately predict sail performance, a numerical design tool must be able to adjust the analysis to sailing conditions (boat speed and direction) that are strictly related to hull performance. For this reason, sail design is generally approached within Velocity Prediction Program (VPP) environments, which estimate the overall performance of the boat by modeling the multiple physics involved in sailing mechanics.


To develop a sail shape optimization procedure for an A-Class catamaran on HPC architecture, Design Methods, RBF-Morph and the University of Rome Tor Vergata (Italy), used ANSYS CFD solutions. The procedure involved coupling ANSYS Fluent aerodynamic analysis to an analytical velocity prediction program (VPP) system to solve the six-degrees-of-freedom boat equilibrium problem in an iterative manner. The sail shape parameterization acted directly on the numerical CFD domain by mesh morphing using RBF-Morph. The aerodynamic analysis was performed assuming a wind boundary layer profile at far-field, with fixed velocity and sailing direction (updated in an iterative cycle within the VPP environment). The computations were performed by double phase steady-state CFD runs using the VOF formulation at several speeds, attitudes and displacements.

Business Benefit:

Design Methods is an engineering company that provides multidisciplinary consulting and design services using state-of-the-art aerospace technologies. The development of methodologies like the described sail design tool is strategic to prove the company’s capability to offer services at the highest technological levels in fields other than aerospace. With this CFD-based sail shape optimization procedure, they can offer a premium design service to sailmakers, sailing teams or any private ship owner who wishes to improve the performance of a sailing ship.

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