IUGG 2003 Abstract

JSP10 Rotating and Stratified Fluids (IAPSO, IAGA, IAMAS, SEDI) Thursday, July 10 AM Location: Site B, Room 21

TIME [ 1120 ] [ JSP10/10A/B21-007 ]

INTERACTION OF DECAYING 2D TURBULENCE WITH RIGID BOUNDARIES: LABORATORY EXPERIMENTS

Yakov D. AFANASYEV(Department of Physics and Physical Oceanography.,Memorial University of Newfoundland)

Jennifer WELLS(Department of Physics and Physical Oceanography.,Memorial University of Newfoundland)

Results from a new series of experiments on quasi-two-dimensional turbulence decaying in a rectangular container are presented. The flows are generated electromagnetically in a thin layer of conducting fluid when different configurations of permanent magnets are used to specify the initial characteristics of the flow. The Particle Image Velocimetry method is used to determine the velocity and vorticity fields. These fields are further used to determine the global characteristics of the flow such as the energy, enstrophy and the net angular momentum with respect to the centre of the container. The experimental results demonstrate that variations of net angular momentum occur due to the interactions of coherent vortex dipoles/jets with the walls of the container. The variation of the angular momentum of the system which occurs due to the action of stresses at the solid boundary can be obtained quantitatively if the initial linear impulse exerted by the magnets on the fluid is known. The analysis of external forces and torques allows one to predict that during the intermediate state of the flow evolution a pattern of the flow will be a rotating quadrupole.