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Augier, Benoit; Hauville, Frédérick; Bot, Patrick; Deparday, Julien; Durand, Mathieu. |
A numerical investigation of the dynamic Fluid Structure Interaction (FSI) of a yacht sail plan submitted to harmonic pitching is presented to analyse the effects of motion simplifications and rigging adjustments on aerodynamic forces. It is shown that the dynamic behaviour of a sail plan subject to yacht motion clearly deviates from the quasi-steadytheory. Theaerodynamicforcespresentedasafunctionoftheinstantaneousapparentwindangleshow hysteresis loops. These hysteresis phenomena do not result from a simple phase shift between forces and motion. Plotting the hysteresis loops in the appropriate coordinate system enables the associated energy to be determined. This amount of exchanged energy is shown to increase almost linearly with the pitching reduced... |
Tipo: Text |
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Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00601/71282/69689.pdf |
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Deparday, Julien; Augier, Benoit; Bot, Patrick. |
In the present study we investigate the flapping instability of a light, soft, highly cambered membrane subject to wind loading. An original in-situ experiment is developed where time-resolved pressures and forces are measured on a full-scale yacht downwind sail called a spinnaker. Particular features of this aero-elastic problem are that the membrane is weakly constrained – held only at three corners –, has a free leading edge, and has no proper shape in the absence of wind loading. In usual operating conditions, the soft structure is subject to a flapping instability giving rise to almost periodic folding and unfolding of the fore part of the sail, associated to strong variations of pressures and forces. This dynamic behavior is analyzed in detail and... |
Tipo: Text |
Palavras-chave: Fluid structure interaction; Full-scale experiment; Modal decomposition; Pressure measurements; Soft membrane. |
Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00444/55561/60479.pdf |
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Aubin, Nicolas; Augier, Benoit; Sacher, Matthieu; Bot, Patrick; Hauville, Frédéric; Flay, Richard G.j.. |
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 (βAW = 60°) unheeled configuration. This study presents dynamic fluid structureinteractionresultsinwellcontrolledconditions(wind,sheetlength)withadynamictrimming system. Trimming oscillations are done around an optimum value of CFobj previously found with a static 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... |
Tipo: Text |
Palavras-chave: Wind tunnel; Upwind; Unsteady; Fluid-structure interaction. |
Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00597/70919/69157.pdf |
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Deparday, Julien; Bot, Patrick; Hauville, Frédéric; Augier, Benoit; Rabaud, Marc; Motta, Dario; Le Pelley, David. |
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 verge of luffing requires continual adjustments. The propulsive force generated by the offwind sail depends on this trimming and is highly fluctuating. During a flapping sequence, the aerodynamic load can fluctuate by 50% of the average load. On a J/80 class yacht, we simultaneously measured time-resolved pressures on the spinnaker, aerodynamic loads, boat data and wind data. Significant spatio-temporal patterns were detected in the pressure distribution. In this paper we present averages and main fluctuations of pressure distributions... |
Tipo: Text |
Palavras-chave: Full scale experiment; Instrumented boat; Spinnaker; Fluid structure interaction; POD; Unsteady. |
Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00597/70918/69156.pdf |
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