MC 5501

## Speaker

Prof. Morris Flynn

## Title

Gravity current flow in density-stratified media and porous media filling box flow: towards improved models of environmental transport

## Abstract

Models describing environmental transport must inevitably include a description of buoyancy-driven flow.

One such flow is a gravity current, which is produced when a mass of fluid flows horizontally into a second fluid of greater or lesser density. Whereas the problem of a gravity current propagating through a uniform ambient has been the topic of rigorous study, much less is known about gravity current flow in a density-stratified medium. In this case, a dynamic coupling exists between the gravity current front and the internal waves this front excites. I will consider this problem from the vantage point of a two-layer ambient and will thereby characterize, via theory and laboratory/numerical experiments, the order-one influence exerted by the internal waves. Implications for effluent dispersion will briefly be discussed.

A second category of buoyancy-driven flow is plume flow. Turbulent plume theory has, for over 50 years, enjoyed great success in describing convection and dispersion. Making the plume laminar and having it fall through a porous medium yields a problem of fundamental significance in its own right, insights from which may be applied, for example, in minimizing groundwater contamination. In the latter half of my talk, I will review the theory relevant to porous media plumes and will then outline a problem in which discharged plume fluid first accumulates then drains from a "leaky" control volume. Model predictions will be shown to be in good agreement with the results of similitude laboratory experiments. Extensions of this research to nonuniform porous media will be considered.

## Bio

Morris R. Flynn is an associate professor of mechanical engineering at the Univ. of Alberta with interests in environmental, architectural and biological fluid mechanics plus the continuum modeling of traffic flow. He completed a Ph.D. in engineering science at the Univ. of California, San Diego in 2006 and subsequently worked as an instructor and researcher at MIT in 2007 and 2008.