Applied Math Colloquium

Friday, Sep 28, 2012, 11:30 AM
Cullimore Lecture Hall, Lecture Hall II
New Jersey Institute of Technology


Dispersion of Particles on Fluid-Liquid Interfaces

Pushpendra Singh


Department of Mechanical Engineering, NJIT



When small particles, e.g., glass, flour, pollen, etc., come in contact with a fluid-liquid interface they disperse so quickly to form a monolayer on the surface that it appears explosive, especially on the surface of mobile liquids like water. This is a consequence of the fact that a particle coming in contact with a liquid surface is pulled into the surface by capillary force causing the particle to accelerate to a relatively-large velocity in the direction normal to the surface. This vertical motion of the particle gives rise to a lateral flow on the surface away from the particle. PIV measurements show that the adsorption of a spherical particle causes a transient axisymmetric flow about the vertical line passing through the center of the particle. The flow develops in a fraction of second after the adsorption of the particle and persists for several seconds. The fluid directly below the particle rises upwards and near the surface it moves away from the particle.

Bio: Dr. Pushpendra Singh received his B.S. form IIT Kanpur in 1985, and M.S. and Ph.D. from the University of Minnesota in 1989 and 1991, respectively. He did postdoctoral at the University of California, Santa Barbara from 1991-1995, and was a technical staff member at Los Alamos National Laboratory from 1995-1996. He joined New Jersey Institute of Technology in 1996 as an Assistant Professor, and since 2005 has been Professor of Mechanical Engineering. He is a fellow APS and ASME. His research interests include non-Newtonian fluid mechanics, biological fluid mechanics, micro-fluidics, computational fluid dynamics, multiphase flows and their manipulation using electric fields, and self-assembly of particles at fluid-liquid interfaces.