After studies in Brest, France and work in the Netherlands in naval engineering, Julien reoriented his career path in academia and in aerodynamics. The conversion went naturally as he completed his PhD on sail aerodynamics in an engineering school, at the French Naval Academy.
His main field of expertise is experimental fluid dynamics. During his PhD, he developed and used an in-situ multi-sensor measurement system to study the effect of wind, a highly detached flow on large and soft membranes that are downwind sails.
He also conducted experiments in wind tunnels at the Yacht Research Unit in Kiel, Germany and at the University of Auckland, New-Zealand.
As a teaching and research assistant, he also taught about 100 hours per year of lectures, tutorials and practical works to master students. He was also the PhD student representative during 3 years and participated in research councils and was part of the board of the institute.
He is interested in unsteady aero-hydrodynamics, fluid-structure interaction and experiments. He is now a post-doctoral researcher in UNFoLD, in the Mechanical Engineering Institute since fall 2017.
His current work is mainly on the experimental study of the aerodynamic performance of vertical axis wind turbine (VAWT) at UNFoLD.
At the blade and rotor level, large variations in both the angle of attack and the magnitude of the incident flow velocity induce strong unsteady flow separation and reattachment.
An objective of this SMART-H project is to devise a generalised physics-based dynamic stall description based on systematic experiments of dynamic stall on a two-dimensional blade in a rotating and non-rotation environment mimicking VAWT operation conditions, to improve prediction capabilities of blade loading, aerodynamic robustness, and performance of VAWT.
This SMART-H project is supported by the Swiss national science foundation under grant number PYAPP2_173652.
My advice to those who wish to learn the art of scientific prophecy is not to rely on abstract reason, but to decipher the secret language of Nature from Nature's documents, the facts of experience.
in Experiment and Theory in Physics, 1944.
Max Born (1882-1970)
Le hasard ne favorise l'invention que pour des esprits préparés aux découvertes par de patientes études et de persévérants efforts.
Louis Pasteur (1822-1895)
Allow me to express now, once and for all, my deep respect for the work of the experimenter and for his fight to bring significant facts from an inflexible Nature who says so indistinctly "No" and so distinctly "Yes" to our theories.
Hermann Weyl (1885-1955)
En essayant continuellement on finit par réussir. Donc plus ça rate, plus on a de chance que ça marche.
The child grows, but is still an experimenter: he grasps at the moon, and his failure teaches him to respect distance. At length his little fingers acquire sufficient mechanical tact to lay hold of a spoon. He thrusts the instrument into his mouth, hurts his gums and thus learns the impenetrability of matter. He lets the spoon fall, and jumps with delight to hear it rattle against the table. The experiment made by accident is repeated with intention, and thus the young student receives his first lessons upon sound and gravitation. There are pains and penalties, however, in the path of the enquirer: he is sure to go wrong, and Nature is just as sure to inform him of the fact. He falls downstairs, burns his fingers, cuts his hand, scalds his tongue, and in this way learns the conditions of his physical well being. This is Nature's way of proceeding, and it is wonderful what progress her pupil makes.
in Fragments of Science, vol. 1, p. 283. Appendix
John Tyndall, Irish-born british physicist (1820-1893)
Fools say that they learn by experience. I prefer to profit by others' experiences.
Prince Otto von Bismarck
The case - said Sherlock Holmes, as we chatted over our cigars that night in our rooms at Baker street - is one where... we have been compelled to reason backwards from effect to cause. Chapter 3
Sir Arthur Conan Doyle
experimental fluid dynamics,
fluid structure interaction,
|Teaching and research assistant||French Naval Academy Research Institute, Brest, France||2012-2016|
|Naval engineer||C-Job Naval Architects, Hoofddorp, the Netherlands||2010-2012|
|PhD||Mechanics, Fluid mechanics and energy||Université Bretagne Occidentale-Naval Academy||2012-2016|
|Msc.Eng||Naval and offshore architecture, specialisation in hydrodynamics||ENSTA Bretagne, Brest, France||2007-2010|
|Aubin, N., Augier, B., Deparday, J., Sacher, M., and Bot, P.
Ocean Engineering, 169, 370-378, 2018
|Performance enhancement of downwind sails due to leading edge flapping: A wind tunnel investigation|
|Deparday, J., and Mulleners, K.
Journal of Physics: Conference Series, 1037, 022017, 2018
|Critical evolution of leading edge suction during dynamic stall|
|Deparday, J., Augier, B., and Bot, P.
Journal of Fluids and Structures, 81, 547-564, 2018
|Experimental analysis of a strong fluidâstructure interaction on a soft membraneâApplication to the flapping of a yacht downwind sail|
|Deparday, J., Bot, P., Augier, B., Rabaud, M., Motta, D., and Le Pelley, D.
Journal Of Sailing Technology,2017-05, 2017
|Modal Analysis of Pressures on a Full-Scale Spinnaker|
PhD Thesis, IRENav, UBO, p.230, 2016
|Experimental studies of Fluid-Structure Interaction on Downwind sails|
|Deparday, J., Bot, P., Hauville, F., Augier, B., and Rabaud, M.
Ocean Engineering, 127, 135-143, 2016
|Full-scale flying shape measurement of offwind yacht sails with photogrammetry|
|Motta, D., Flay, R.G.J., Richards, P.J., Le Pelley, D.J., Deparday, J., and Bot, P.
Ocean Engineering, 90, 104-118, 2014
|Experimental investigation of asymmetric spinnaker aerodynamics using pressure and sail shape measurements|