Upwind sail aerodynamics : A RANS numerical investigation validated with wind tunnel pressure measurements
TypeArticles dans des revues avec comité de lecture
The aerodynamics of a sailing yacht with different sail trims are presented, derived from simulations performed using Computational Fluid Dynamics. A Reynolds-averaged Navier-Stokes approach was used to model sixteen sail trims first tested in a wind tunnel, where thepressure distributions on the sails were measured. An original approach was employed byusing two successive simulations: the first one on a large domain to model the blockage due to the wind tunnel walls and the sails model, and a second one on a smaller domain to model the flow around the sails model. A verification and validation of the computed aerodynamic forces and pressure distributions was performed. The computed pressure distribution is shown to agree well with the measured pressures. The sail surface pressure was correlated with the increase of turbulent viscosity in the laminar separation bubble, the flow reattachment and the trailing edge separation. The drive force distribution on both sails showed that the fore part of the genoa (fore sail) provides the majority of the drive force and that the effect of the aft sail is mostly to produce an upwash effect on the genoa. An aerodynamic model based on potential flow theory and a viscous correction is proposed. This model, with one free parameter to be determined, is shown to fit the results better than the usual form drag and induced drag only, even if no friction drag is explicitly considered.
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BOT, Patrick; MARIA VIOLA, Ignazio; FLAY, Richard G.J.; BRETT, Jean-Sebastien (Elsevier, 2014)This paper describes an experiment that was carried out in the Twisted Flow Wind Tunnel at The University of Auckland to measure a detailed set of pressure distributions on a rigid 1/15th scale model of a modern asymmetric ...
Proceedings of the 1st International Conference on Innovation for High Performance Sailing Yachts INNOV’SAIL BOT, Patrick (RINA, 2008)Proceedings of the 1st International Conference on Innovation for High Performance Sailing Yachts INNOV’SAIL
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 ...
Numerical study of a Flexible Sail Plan submitted to pitching : Hysteresis phenomenon and effect of rig Adjustments AUGIER, Benoit; HAUVILLE, Frédéric; BOT, Patrick; AUBIN, Nicolas; DURAND, Mathieu (Elsevier, 2014)A numerical investigation of the dynamic Fluid Structure Interaction (FSI) of a yacht sail plan submitted to harmonic pitching is presented to analyse the system's dynamic behaviour and the effects of motion simplifications ...