Eddy Viscosity in Dense Granular Flows

We built a new experimental set-up to investigate 2D Granular flows at fixed pressure. The striking result is that the velocity profi les exhibit a S shape, and are not linear as local constitutive laws would predict. Phys. Rev. Letter [pdf]

Heat Transfer across sheared suspensions: Role of sheared induced diffusion

Suspensions of non-Brownian spherical particles undergoing shear provide a unique system where mixing occurs spontaneously at low Reynolds numbers. Through a combination of experiments and simulations, we investigate the effect of shear-induced particle diffusion on the transfer of heat across suspensions. J. Fluid Mech. [pdf]

How vortices mix ?

We use a passive-Brownian-tracer method to investigate mixing in rotational vortices. The effective mass diffusivity scales as a power law of the Peclet Number... Physics of Fluids [pdf]

Irreversibility and Chaos: Role of Lubrication Interactions in Sheared Suspensions

We investigate non-Brownian particles suspended in a periodic shear-flow using simulations. Following a previous paper [Phys. Rev. E 82, 051406], we show that the chaotic dynamics arising from lubrication interactions are too weak to generate an observable particle dispersion. Phys. Rev. E [pdf]

Taylor's experiment revisited: Clouds of particles in periodic shear flow

We have investigated the time evolution of a cloud of non-Brownian particles subjected to a periodic shear flow in an otherwise pure liquid at low Reynolds number. This experiment, reminiscent to the famous experiment of Taylor, illustrates the irreversible nature of particulate systems submitted to a shear. Two distinct patterns, including a “galaxy-like” shape, are observed for the evolution of the clouds and the transition between the patterns is identified using a simple scaling analysis. Phys. Fluids [pdf]

Evolution of a cloud of particles submitted to a periodic shear flow: pictures taken at the end of each cycle of shear