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W. G. Pritchard Lab Seminar: 3:30-4:30 PM, 104 McAllister Building

	             **Monday April 19, 2004**
	
Dynamics of cooling viscoplastic fluids

Neil Balmforth

Department of Mathematics
Massachusetts Institute of Technology
 

Abstract:

Many problems in geophysics involve the flow of a non-Newtonian fluid. 
Examples include mudslides (clay slurries are one of the most frequently 
cited examples of viscoplastic fluids), the spreading of lava (which 
acquires a yield stress once it begins to cool and silicates crystallize), 
and the movement of ice (according to Glenn's flow law, ice is a shear-
thinning non-Newtonian material). There are also counterparts of these 
problems in chemical engineering, where, although the emphasis typically 
shifts towards different objectives, the need to understand the fundamental 
fluid mechanics remains the same. In this talk I will describe efforts to 
model these kinds of fluid flows, beginning with some mathematical analysis 
of the governing fluid  equations which furnishes a simpler system of 
equations to describe the flow dynamics; a ``shallow lava model'' in the 
context of volcanology. The simplified model enables a concise exploration 
of how viscoplastic fluids spread over inclined planes, and how domes that 
cool from their surface expand on a flat surface.

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