Wind-tunnel pressure measurements on model-scale rigid downwind sails
TypeArticles dans des revues avec comité de lecture
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 spinnaker. It was observed that the pressures varied considerably up the height of the spinnaker. The fine resolution of pressure taps allowed the extent of leading edge separation bubble, pressure recovery region, and effect of sail curvature to be observed quite clearly. It was found that the shape of the pressure distributions could be understood in terms of conventional aerodynamic theory. The sail performed best at an apparent wind angle of about 55°, which is its design angle, and the effect of heel was more pronounced near the head than the foot. Analysis of pressure time histories allows the large scale vortex shedding to be detected in the separation region, with a Strouhal number in the range 0.1 – 0.3, based on local sail chord length.
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BOT, Patrick; MARIA VIOLA, Ignazio; FLAY, Richard G.J.; BRETT, Jean-Sébastien (Ecole Navale, 2013)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 ...
Experimental Investigation of Asymmetric Spinnaker Aerodynamics Using Pressure and Sail Shape Measurements MOTTA, Dario; FLAY, Richard G.J.; RICHARDS, P.J.; LE PELLEY, David; DEPARDAY, Julien; BOT, Patrick (Elsevier, 2014)An innovative method combining simultaneous on-water pressure and sail shape measurements for determining aerodynamic forces produced by sails is described and used on Stewart 34 and J80 Class yachts flying asymmetric ...
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 ...
FLAY, Richard G.J.; PIARD, A; BOT, Patrick (2017)While the aerodynamics of upwind sails are relatively well understood, flows past downwind sails are still very challenging. Indeed, downwind sails which can be considered as highly cambered thin wing profiles, are well ...
VIOLA, I.M; BOT, Patrick; RIOTTE, M. (Wiley, 2013)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 ...