Turbulence

Research groups

Rheology and dynamics of dense, turbulent fluid-solid flows

Turbulent, dense fluid-particle flows are commonly encountered in engineering processes such as in air jet mills as well as terrestrial and extra-terrestrial phenomena, e.g., bedload sediment transport, movement of sand dunes, impingement of jets on planetary surfaces. High speed fluid flows on dense beds are complex in nature because of the coupling between the fluid and solid phases.

Polymer Dynamics in Turbulent Flows

Adding even a small amount of dissolved polymer into a fluid can have a dramatic impact on the way it flows. If the flow is turbulent (high-Reynolds-number) to begin with, then the polymer can strongly modify the turbulent eddies and reduce the drag force (in flow through pipes) or even make the flow laminar. Known as the Toms effect, this phenomena is exploited to reduce the pumping costs associated with transporting oil in pipelines. Polymers can also destabilize a low-Reynolds-number steady flow and make it unsteady and chaotic.