What We Do

The Cardiovascular and Multiphase Flows Lab works on fundamental problems in fluid mechanics that arise in turbulent and complex, unsteady flows, in many cases with the addition of a second disperse phase. Turbulence is one of the last answered question in classical physics. When more than one phase is present, such as when liquid droplets are injected into a gas stream, or when air bubbles are introduced into a water flow, new and interesting phenomena occur that are both scientifically challenging and relevant to many engineering and environmental applications. Our approach is to perform experiments, complemented with numerical simulations and theoretical analysis, in order to probe the fundamental physical processes involved. Once the key features of the problem are understood, we develop a quantitative model that can be incorporated into large scale, multiphysics models for applications.

Examples of fluid mechanics problems that we are addressing are the dynamics of water droplets or solid spherical particles in a turbulent air flow; the hydrodynamics of microbubbles in non-uniform flows; the breakup, transport and impact of liquid droplets made up of complex fluids; the influence of fluid and solid mechanics on the origin and progression of cardiovascular disease on the carotid bifurcation and on arterio-venous fistulas for dialysis access. We are also involved in the study of tidal and in-stream turbines for renewable energy generation from marine currents. This project is part of the National Northwest Marine Renewable Energy Center created in the Fall of 2008 by the US Department of Energy to advance marine renewable energy conversion in the US. Our interest is in modeling, numerically and experimentally, the flow around turbine blades and the resulting wake, with a particular emphasis on wake turbine interactions and short range environmental effects, such as pressure fluctuations and sediment transport.

Impact and Spreading of a Complex-Rheology Liquid Droplet on a Solid Surface at high Ohnesorge and Weber numbersTurbulent Jet Visualization via Planar Laser-Induced Fluorescence