Open AccessDynamics of a laminar plume in a cavity: The influence of boundaries on the steady state stem structure
Author(s) -
Keken P. E.,
Davaille A.,
Vatteville J.
Publication year - 2013
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2012gc004383
Subject(s) - plume , prandtl number , mechanics , laminar flow , thermal , geology , outflow , core–mantle boundary , geophysics , boundary value problem , physics , mantle (geology) , thermodynamics , convection , oceanography , quantum mechanics
The steady state structure of thermal plumes rising from a small heater is studied in high Prandtl number fluids. We show good agreement between laboratory experiments and numerical simulations. We study the effect of the boundaries on the plume development by numerically simulating the plume rise in very large geometries. The thermal structure of the plume axis is similar for all box sizes considered, but the velocity structure changes strongly as box sizes are increased. We show that the effect of the side boundaries becomes unimportant for large aspect ratio, but that the free‐slip top boundary has a strong influence on the velocity structure under all conditions. We show that the use of an outflow boundary condition significantly reduces the influence of the top boundary. Under these conditions we recover to good precision the theoretical predictions for plumes rising in an semi‐infinite half‐space. The strong influence of the boundaries in high Prandtl number fluids is important in the interpretation of laboratory experiments and numerical simulation for the dynamics of the Earth's mantle.