PHYSICAL MATHEMATICS SEMINAR


TOPIC:		ENTRAINMENT IN ROTATING CONVECTIVE PLUMES


SPEAKER:	SONYA LEGG
		Woods Hole Oceanographic Institute


ABSTRACT:

In many geophysical scenarios, convection may be significantly
influenced by planetary rotation. Convection typically takes place in the
form of discrete plumes, which may expand through the turbulent
entrainment of surrounding fluid.  Here numerical simulations of turbulent
convection are examined to show that strong rotation can modify this
entrainment.  Two scenarios are considered: first upright convection
driven by surface buoyancy fluxes, and second gravity plumes along sloping
topography.  In upright convection entrainment is suppressed by strong
rotation. Instead plume-plume interactions lead to stirring which dilutes
the plume buoyancy and reduces heat transport.  In gravity plumes the
mechanism of entrainment is through shear instability.  When rotation is
strong the shear is reduced, and instead entrainment takes place through
lateral motions.


DATE:		TUESDAY, OCTOBER 16, 2001

TIME:		2:30 PM

LOCATION:	Building 2, Room 338


Refreshments will be served at 3:30 PM in Room 2-349

Massachusetts Institute of Technology
Department of Mathematics
Cambridge, MA  02139