HR: 16:30h
AN: V34B-03    [Abstracts]
TI: An Experimental Investigation of Phase Mingling in a Subaqueous Volcanic Eruption
AU: * Friedman, P D
EM: pfriedman@umassd.edu
AF: University of Massachusetts Dartmouth, 285 Old Wstport Rd., Dartmouth, MA 02747 United States
AU: Carey, S
EM: scarey@gso.uri.edu
AF: The University of Rhode Island Graduate School of Oceanography, Horn 109, Narragansett, RI 02882 United States
AU: Meyer, W J
EM: u_wmeyer@umassd.edu
AF: University of Massachusetts Dartmouth, 285 Old Wstport Rd., Dartmouth, MA 02747 United States
AB: Experimental simulations have been conducted to model phase mingling in subaqueous volcanic eruptions in the absence of heat transfer. The experiments use Particle Image Velocimetry to map the flow structure of experimental surrogates for magma and water. The surrogates were selected to match indices of refraction to allow flow visualization within the two-phase fountain. A fluorescent dye that is soluble in only one of the fluids is used to mark phase boundaries. While these are simplified first-order experiments that examine only fluid dynamics, assuming a complete decoupling from heat transfer and expansion, they nevertheless reveal important flow characteristics that are necessary precursors to phreatomagmatic explosions. Phase mingling results from flow instabilities that occur below a threshold Richardson number, including engulfment from fountain collapse and rollup engulfment. Vent geometry is important in establishing flow conditions such as initial vorticity, which reduce the threshold Richardson number for mingling onset.
DE: 8427 Subaqueous volcanism
DE: 8428 Explosive volcanism
DE: 8445 Experimental volcanism
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005