HR: 0800h
AN: T41C-1323    [Abstracts]
TI: Flow structure, entrainment and stirring in thermal plumes: a laboratory view
AU: * Cotel, A
EM: acotel@umich.edu
AF: Dept. of Civil and Environmental Engineering, 1351 Beal Avenue University of Michigan, Ann Arbor, MI 48109-2125 United States
AU: Lithgow-Bertelloni, C
EM: crlb@umich.edu
AF: Dept. of Geological Sciences, 1100 N. University Avenue University of Michigan, Ann Arbor, MI 48109-1005 United States
AB: Although many have studied the chemistry and dynamics of mantle plumes, fundamental questions remain. These can be grouped into two general issues: a) Plume structure and dynamical interaction with the surrounding mantle, b) The degree of entrainment and stirring in mantle plumes of chemically distinct material from the deep mantle. We address these fundamental questions by performing detailed fluid dynamical experiments to determine the structure, velocity, and degree of entrainment in a single thermal plume. Heat is used as the driving convective mechanism to form a single mantle plume. The experiments are conducted in a Plexiglas tank (30 cm³). A short copper cylinder, 3 cm tall with a diameter of .25 cm, is connected to a heater and is attached to the center of the tank bottom. By varying voltage settings we can simulate varying heat fluxes in the deep mantle. We employed several visualization techniques in our experiments: shadowgraph, Particle Image Velocimetry (PIV), and Laser Induced Fluorescence (LIF). Penetration height and plume head size are related to the varying buoyancy flux. In addition, velocity and vorticity fields determined using Particle Image Velocimetry provide insight into the plume structure and the nature of the entrainment process.
DE: 8121 Dynamics: convection currents, and mantle plumes
DE: 8137 Hotspots, large igneous provinces, and flood basalt volcanism
SC: Tectonophysics [T]
MN: Fall Meeting 2005