[FLASH-BUGS] implicit thermal conduction

[Elke Roediger]

Dear FLASH team,

I have a problem with the implicit thermal conduction module in FLASH4.

I set up a simple test problem: 2D simulation box, constant pressure, temperature T1 in upper half, temperature T2 in lower half; i.e. a two fluids with different temperatures separated by an interface along the x-axis. Thermal conduction must work along the vertical direction and erase the temperature discontinuity. 

I want the hydrodynamic boundary conditions in x-direction to be periodic, and "outflow" boundaries in the y-direction. When I do this, the temperature at the left and right boundary of the simulation box drops to something very small (probably zero), and I get thermal conduction not only in the vertical direction, but also on the horizontal direction. When I change the x-boundaries to "outflow" it works fine.

I rotated the whole geometry, i.e. interface between the hot and cold is along the y-axis, and the periodic boundaries along the y-axis, that works fine. 

I am aware that the implicit diffusion solver needs some boundary conditions too, they are set to "outflow" for all directions.

Can you spot where the problem is?

Best regards,
Elke Roediger



-------------------------------
Dr. Elke Roediger
eroediger at hs.uni-hamburg.de
+49 (0)40/42838-8539

Hamburger Sternwarte
Universitaet Hamburg
Gojensbergsweg 112
D-21029 Hamburg
Germany