Wednesday, March 07, 2007, 11am - 12pm, MDEA

Fluid dynamics of multiphase flows in micro-fluidic devices

Pushpendra Singh

Department of Mechanical Engineering
New Jersey Institute of Technology
Newark, NJ 07102

Abstract

We use the direct numerical simulation (DNS) approach to simulate multiphase flows containing particles and droplets in micro-fluidic devices. The fluid-particle motion is resolved by the distributed Lagrange multiplier method and the interface is moved by the level set method. In the presence of an externally imposed electric field, the electric stresses are computed in terms of the Maxwell stress tensor. The code is used to study the transient and steady state motion of bubbles rising in a viscoelastic liquid modeled by the Oldroyd-B constitutive equation. Simulations show that there exists a critical bubble volume at which there is a sharp increase in the terminal velocity with increasing bubble volume similar to the behavior observed in experiments, and that the shape of the bubble and its wake structure change fundamentally at this critical volume. If time permits, I will also discuss our work on the use of electric fields to manipulate drops and particles in micro-fluidic devices.

 

Brief Biography

Professor, New Jersey Institute of Technology (1996-present)
Technical Staff member, Los Alamos National Laboratory (1995-96)
Postdoc, University of California, Santa Barbara (1991-1995)
Ph.D., University of Minnesota (1991)
M.S., University of Minnesota (1989)
B.Tech., Indian Institute of Technology Kanpur, India (1985)