Fluid Mechanics Seminars
Abstracts 2004-2005
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479 EBU-II
Professor Hai Wang
“Transport Properties of Nanoparticles in Low-Density Gases - Theory and
Applications”
Transport theory will be
addressed for small spherical particles beyond the Stokes equation with
Cunningham slip correction. Relationships among the Chapman-Enskog theory of molecular diffusion, the Epstein theory of
drag and the Stokes equation with Cunningham slip will be discussed, showing
how these theories can be unified by an analytical expression derived from
gas-kinetics theory. The talks will end with a discussion of the nature
of diffuse scattering as revealed by molecular dynamics simulations. The
application of the unified theory will also be discussed in the context of nanoparticle synthesis in reacting flows.
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479 EBU-II
Professor Sergei Krasheninnikov
Department of
“Dust dynamics in fusion plasmas”
Significant amounts of dust have been observed in the chambers of
fusion devices. The existence of dust particles in next-step fusion devices,
however, may potentially pose a significant safety threat due to the
accumulation of hardly containable toxic and radioactive materials retaining
tritium. Here we demonstrate that due to acceleration by plasma flows in the
vicinity of material surface, dust particles can acquire very high speed.
Interactions of dust particles with corrugated surface or plasma turbulence can
cause an escape of dust particle to from near wall region so that dust can fly
toward tokamak core. It is likely that dust formation
in and transport from divertor region can play an
important role in core plasma contamination. Current experimental observations
support this qualitative physical picture.
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479 EBU-II
“Internal waves in the atmosphere
and oceans”
Internal waves are common and important features of atmospheric and oceanic flows. In this talk I will describe some observations and give a brief review of the fundamental properties of internal waves. Then I will describe a new procedure that combines ray and Fourier methods for efficiently computing linear internal wavefields in flows with depth dependent background shear and stratification. This procedure will be used to compute the internal wave field generated by stratified atmospheric flow over a three-dimensional mountain and that generated by a horizontally moving and vertically oscillating source, representing a sphere and its turbulent wake, in a stratified fluid.
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For information: Bruno Etchepare at (858) 534-6029