[Nek5000-users] Conjugate Heat Transfer

[nek5000-users at lists.mcs.anl.gov]

Hi,

I have experienced some difficulties with setting up a 2D conjugate heat 
transfer problem. When generating the .rea file with prenek, I create a 
mesh of, say 60 elements and define, say, 20 of those as solids 
(material group 1 instead of 0). Trying to run this .rea file in genmap 
(even when it is converted to re2) does not work since the fluid 
boundary condition section of the .rea file contains entries for 
elements (the solids) without connectivity/boundary information. 
Deleting those entries (4*20 lines for 2D) lets genmap accept the rea 
file and a map is created with one section for the fluids elements and 
one for the solids.
Running these files with nek5000, however, resulted in element mismatch 
errors, no matter what combination of solid elements vs. number of 
processors I tried. The newest nek5000 svn was used.

The solution I found is the following: when one takes the .rea file for 
conjugate heat transfer (as it came out of prenek) and changes all solid 
elements back to fluids, a map can be generated from this 
only-fluids-.rea file with genmap that is essentially left in ignorance 
of the conjugate heat transfer problem/solid elements. Running this 
"fluids-only" map with the original "conjugate heat"-.rea file (having 
deleted the solid elements boundary/connectivity information in its 
fluids section) will work and produces physically correct looking results.

My questions now are the following:
-Is this an appropriate way to go or am I missing some parameters that 
need to be set? The rea files come directly out of prenek, so I didn't 
manually change any parameters.
-By generating a map file that does not resemble what's truly going on, 
do we loose parallel scalability and if so, is that a considerable penalty?
-I had some trouble defining solid elements in 3D with prenek. Whenever 
I click on an element to change its material group, it does not do it. 
Is there a fix?
-Expanding a 2D conjugate heat transfer problem with n2to3 does not 
work. All upper level elements become solids. Is there a fix for this?

I apologize for my lengthy postings,
Markus