Julien Deparday
Experimental fluid dynamics. My research and experience.
Archives
Performance enhancement of downwind sails due to leading edge flapping: A wind tunnel investigation
in Ocean Engineering, 169:370–378, 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 (panel layout) and two different sail materials are tested at various wind speeds and wind angles in a…
Experimental analysis of a strong fluid-structure interaction on a soft membrane – Application to the flapping of a yacht downwind sail
in Journal of Fluids and Structures, 81:547–564, 2018 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…
Modal Analysis of Pressures on a Full-Scale Spinnaker
in Journal of Sailing Technology, 05:1–21, 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 verge of luffing requires continual adjustments. The propulsive force generated by the…
Full-scale flying shape measurement of offwind yacht sails with photogrammetry
in Ocean Engineering, 127:135–143, 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 Interaction, but need experimental validation. It remains complex to measure spinnaker flying shapes partly because of their inherent…
Experimental investigation of asymmetric spinnaker aerodynamics using pressure and sail shape measurements
in Ocean Engineering, 90:104–118, 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 spinnakers. Data were recorded in light and medium winds in order to check the reliability, accuracy and repeatability of…