On the Uncertainty of CFD in Sail Aerodynamics
TypeArticles dans des revues avec comité de lecture
A verification and validation procedure for yacht sail aerodynamics is presented. Guidelines and an example of application are provided. The grid uncertainty for the aerodynamic lift, drag and pressure distributions for the sails is computed. The pressures are validated against experimental measurements, showing that the validation procedure may allow the identification of modelling errors. Lift, drag and L2 norm of the pressures were computed with uncertainties of the order of 1%. Convergence uncertainty and round-off uncertainty are several orders of magnitude smaller than the grid uncertainty. The uncertainty due to the dimension of the computational domain is computed for a flat plate at incidence and is found to be significant compared with the other uncertainties. Finally, it is shown how the probability that the ranking between different geometries is correct can be estimated knowing the uncertainty in the computation of the value used to rank.
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AUGIER, Benoit; BOT, Patrick; HAUVILLE, Frédéric; DURAND, Mathieu (Editions de l'Ecole Polytechnique, 2013)The dynamic Fluid Structure Interaction (FSI) of yacht sails submitted to a harmonic pitching motion is numerically investigated to address both issues of aerodynamic unsteadiness and structural deformation. The model ...
Sharp Transition in the Lift Force of a Fluid Flowing Past Nonsymmetrical Obstacles: Evidence for a Lift Crisis in the Drag Crisis Regime BOT, Patrick; RABAUD, Marc; THOMAS, Goulven; LOMBARDI, Alessandro; LEBRET, Charles (American Physical Society, 2016)Bluff bodies moving in a fluid experience a drag force which usually increases with velocity. However in a particular velocity range a drag crisis is observed, i.e., a sharp and strong decrease of the drag force. This ...
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