Experimental Investigation of Asymmetric Spinnaker Aerodynamics Using Pressure and Sail Shape Measurements
TypeArticles dans des revues avec comité de lecture
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 spinnakers. Data were recorded in light and medium winds in order to check the reliability, accuracy and repeatability of the system. Results showed similar trends to the published literature. The accuracy of the system was investigated by wind tunnel tests, with determination of the entire sail shape from the stripe images recorded by the camera-based (VSPARS) system, and was found to be relatively good. Generally the pressure distributions show a leading edge suction peak, occurring at 5 to 10% of the chord length, followed by a pressure recovery and then a suction increase due to the sail curvature, with finally a reduction in suction near the trailing edge. The drive force coefficient measured on the Stewart 34 is lower than for the J80 because of a non-optimal sail shape due to light winds. On a reaching course, the standard deviation of the pressure signals was largest near the luff, reducing in the stream-wise direction, while it was high on the entire sail section when sailing on a running course.
Files in this item
Showing items related by title, author, creator and subject.
DEPARDAY, Julien; BOT, Patrick; HAUVILLE, Frédéric; AUGIER, Benoit; RABAUD, Marc; MOTTA, Dario; LE PELLEY, David (SNAME, 2017)While sailing offwind, the trimmer typically adjusts the downwind sail “on the verge of luffing”, occasionally letting the luff of the sail flap. Due to the unsteadiness of the spinnaker itself, maintaining the luff on the ...
Performance enhancement of downwind sails due to leading edge flapping: A wind tunnel investigation AUBIN, Nicolas; AUGIER, Benoit; DEPARDAY, Julien; SACHER, Matthieu; BOT, Patrick (Elsevier BV, 2018)This work presents a wind tunnel experimental study on the effect of the leading edge flapping on the aerodynamic performance of a spinnaker. Four J80-class spinnaker models, combining two different assembling structures ...
DEPARDAY, Julien; BOT, Patrick; HAUVILLE, Frédéric; AUGIER, Benoit; RABAUD, Marc (Elsevier, 2016)Yacht downwind sails are complex to study due to their non-developable shape with high camber and massively detached flow around thin and flexible membranes. Numerical simulations can now simulate this strong fluid-structure ...
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 ...
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 ...