THE LEVICH INSTITUTE ANNOUNCES THE FOLLOWING SEMINAR

Tuesday, 11/07/2000
4:00 PM
Steinman Hall, Room #1M-22

Dr. David Jacqmin
NASA
Glenn Research Center

"Two Models of Two-Phase Flow"


ABSTRACT


The talk will contain two parts, both dealing with two-phase flows. The first part will be about phase-field based numerical modeling of two-phase flow. The phase-field approach has been used extensively for nonlinear diffusion problems but has only recently been applied to the Navier-Stokes equations. In the phase-field approach, multi-component fluids are modeled as having local free energy densities that are a function of both local composition and local composition gradients. The fluid divides into phases that have compositions with low energy with the phases separated by finite-thickness diffuse interfaces. Examples of computations (Rayleigh-Taylor instabilities, drop coalescence and break-up, contact-line movement, electrokinetic flows) will be given and issues of model and numerical convergence and stability will be discussed.

The second part of the talk will touch on the stability of coating flows. At high capillary numbers the dynamic contact angle of the wetting liquid approaches 180 degrees. Because of viscous effects, the pressure in the airflow in the half cusp between the wall and liquid could therefore be quite high. Using lubrication theory, an integral-differential equation has been derived that accounts for possible mitigating effects, including compressibility, Knudsen diffusion and diffusion of air into the liquid. Some practical results and their implications for coating flow process design will be given.

BRIEF ACADEMIC/EMPLOYMENT HISTORY: :



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