Flow control

Our approach to flow control is to combine our knowledge of flow natural instabilities to multidisciplinary optimization tools and particle flow solvers.

We have applied this approach to the destruction of tip vortices produced in the wakes of aircraft and to drag reduction in three-dimensional cylinder wakes.

We also use penalization methods to simulate flows around obstacles and analyze passive control methods based on porous coatings.

3D (dash) vs 2D (dash-dot) optimal drag reduction in a cylinder wake for two values of the Reynolds number.
Solid line is the  uncontrolled drag.

Cylinder controlled wake for optimal drag reduction (video)

[1] G.-H. Cottet, I. Sbalzarini, S. Muller and P. Koumoutsakos, Optimization of trailing vortices by Evolution Strategies,  Center for Turbulence Research, Proceedings of the Summer Program, 2000.  pdf file

[2] G.-H. Cottet and P. Poncet, Simulation and control of three-dimensional wakes,   Computers and fluids,  33,  97-713,  2004.  pdf file

[3]  P. Poncet, G.-H. Cottet and P. Koumoutsakos,  Control of three-dimensional wakes using evolution strategies,   C. R. Mecanique 333 (2005),  65-77,  2005. pdf file

[4] P. Poncet, R. Hildebrand, G.-H. Cottet and P. Koumoutsakos, Spatially distributed control for optimal drag reduction of the flow past a circular cylinder, J. Fluid Mech., 599, 111-120, 2008. pdf file

[5] C. Mimeau, I. Mortazavi and G.-H. Cottet , Passive flow control around a semi-circular cylinder using porous coatings, International Journal of Flow Control, 6, 43-50, 2014. pdf file

[6] C. Mimeau, G.-H. Cottet and I. Mortazavi  Direct numerical simulations of three-dimensional flows past obstacles with a vortex penalization method, Computers and Fluids (2016), pp. 331-347. pdf file

[7] C. Mimeau, I. Mortazavi and G.-H. Cottet  Passive control of the flow around a hemisphere using porous media, to appear in European Journal of Mechanics-B/Fluids, 2017. pdf file