Wind tunnel investigation of dynamic trimming on upwind sail aerodynamics
TypeCommunications avec actes
An experiment was performed in the Yacht Research Unit’s Twisted Flow Wind Tunnel (University of Auckland) to test the effect of dynamic trimming on three IMOCA 60 inspired mainsail models in an upwind (AWA = 60 ) unheeled configuration. This study presents dynamic fluid structure interaction results in well controlled conditions (wind, sheet length) with a dynamic trimming system. Trimming oscillations are done around an optimum value of CFobj previously found with a steady trim. Different oscillation amplitudes and frequencies of trimming are investigated. Measurements are done with a 6 component force balance and a load sensor giving access to the unsteady mainsail sheet load. The driving CFx and optimization target CFobj coefficient first decrease at low reduced frequency fr for quasisteady state then increase, becoming higher than the steady state situation. The driving force CFx and the optimization target coefficient CFobj show an optimum for the three different design sail shapes located at fr = 0:255. This optimum is linked to the power transmitted to the rig and sail system by the trimming device. The effect of the camber of the design shape is also investigated. The flat mainsail design benefits more than the other mainsail designs from the dynamic trimming compared to their respective steady situtation. This study presents dynamic results that cannot be accurately predicted with a steady approach. These results are therefore valuable for future FSI numerical tools validations in unsteady conditions.
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AUBIN, Nicolas; AUGIER, Benoit; SACHER, Matthieu; BOT, Patrick; HAUVILLE, Frédéric; FLAY, Richard G.J. (SNAME, 2017)An experiment was performed in the Yacht Research Unit’s Twisted Flow Wind Tunnel (University of Auckland) to test the effect of dynamic trimming on three IMOCA 60 inspired mainsail models in an upwind ( AW = 60°) unheeled ...
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AUBIN, Nicolas; DHOME, Ulisse; AUGIER, Benoit; BOT, Patrick; HAUVILLE, Frédéric (2016-06)Pumping or flicking1 is often used by sailors to get extra propulsion while sailing (subject to restrictions by the racing rules2). Common unsteady sailing situations, due to crew action (e.g. manoeuver like gybing3) or ...
AUBIN, Nicolas; AUGIER, Benoit; BOT, Patrick; HAUVILLE, Frédéric; FLOCH, Ronan (Elsevier, 2016)This work presents a full-scale experimental study of a yacht rig and sails in real upwind sailing conditions and a comparison with Fluid Structure Interaction (FSI) simulations with the ARAVANTI model (Finite Element ...