Porous Media

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I study the flow of a shear thinning non-Newtonian solution within a three dimensional model porous medium made of closely packed glass beads. The fluid is index matched with the glass so using confocal microscopy we are able to probe the dynamics of the flow at the pore scale in the bulk of the medium. Using particle image velocimetry, I have been able to show that after the flow of certain polymeric fluids, the porosity of the system changes considerably. These measurements have direct applications in enhanced oil recovery with polymer flooding.
I am interested in the dynamics of two immiscible fluids in porous media. For certain polymeric solutions the effect of the Non-Newtonian fluid is mainly due to conformance control and absorption of polymer on the surfaces.

Fluid Mechanics

Example image - aligned to the right

We use high speed stereoscopic imaging to study the motion of anisotropic particles in fluid flows. The dynamics of rod-like particles is different from the carrier flow, since these particles align with the directions of history of velocity gradients as they are advected by fluid flow.
We have measured the rotational dynamics of small tracer rods in turbulence and showed that the rotation rate of rods is suppressed due to the alignment of rods with the flow. and rods preferentially sample the flow since their orientations become correlated with the velocity gradient tensor.
In another series of experimental measurements in two dimensional chaotic flows, we have quantified the alignment of rods with the Lagrangian coherent structure of the flow.