Physics Colloquium
Tuesday, January 27th, 2004 4 P.M.
N302 Math/Science Center
Zahir Daya
Geometry dependence of turbulent convection.
Turbulent convection is the primary mechanism of heat transfer
in the earth's atmosphere and oceans and in stellar and planetary
interiors. It is characterized by hot buoyant plumes, cold down-wellings
and
a large scale flow. In this talk I discuss laboratory experiments
on turbulent convection in cells of square and circular cross sections.
The
ratio of the
width to height, the aspect ratio, was approximately
unity. Measurements of the temperature and velocity fluctuations
away
from the lateral
boundaries are found, unexpectedly, to be strongly
dependent on the cell shape. This nonuniversality raises questions
about
plume mixing in the small aspect ratio systems to which experiments
are
limited. I will then introduce turbulent electroconvection in freely
suspended
annular liquid crystal films. This unique system allows us to complement
and extend traditional thermal convection studies to a broader
range
of
aspect ratios.
|
