Thermal convection in 2D movies
The following movies show thermal convection in the infinite Prandl
number, laminar flow limit as appropriate for the Earth's mantle.
The movies were produced for educational purposes with the finite
element code ConMan by Scott
King, and the finite difference code FDCON by Harro
Schmeling
Isoviscous models
The aspect ratio of the computational domain is four (4 x 1 , 2D),
there is no internal heating, fixed thermal boundary conditions on the
top and bottom (heating from below) and free slip along the
boundaries.
The time you see in the title is in nodimensional units and has to
be multiplied by the conductive timescale for real times.
 Rayleigh number 10^6
Quicktime movie (940kB).
Note how an initial disturbance evolves into stable convection cells and
the conductive temperature profile changes. At the end, the system has
reached quasi steadystate.
 Rayleigh number 10^7, initial condition 1
Quicktime movie (2.7MB). Starting from a disturbance, an apparently
stable configuration with higher wavelength than for Ra=10^6 develops.
It is only temporarily stable, however, as can be seen
later when the timedependence takes over.
 Rayleigh number 10^7, initial condition 2
Quicktime movie (900kB). The same model as above develops into timedependence
right away from different initial conditions.
Temperature dependent convection
Under construction, send me email if you are interested in the
visualizations shown in class.
Subduction
A dense, fluid slab sinks into the upper mantle. The rheology is
Newtonian, besides near the surface, where a "Byerlee law" reduces the
material strength, simulating plastic deformation (see Enns et
al., 2005, for an equialent, 2D setup and details). The box is
meant to simulate the upper 1000 km of the mantle; slab thickness is
100 km and slab viscosity is 500 times the mantle viscosity.
Computed using L. Moresi's Citcom FE code with extensions by S. Zhong,
as provided by CIG.
Other links
See also Shijie Zhong's nice Virtual Earth online
thermal convection module at CU Boulder and a collection of links to more
movies on my 440 course web page.
Updated: September 13, 2019
(c) JSG Geodynamics, 2019.
