Add a heat source with a specified heat flux

[RSuryaNarayan]

Hello,

Is there a way to add a heat flux of specified intensity over a region in the domain? This must ideally add a source term to the energy equation and proceed with the solution.

Thanks a lot

[whitmanscu]

I've done this before via modifying PeleC::fill_ext_source in External.cpp to add energy. You then need to specify pelec.add_ext_src = 1 in the inputs file.

I will caution that I've found ignition via this method to be less stable than heat transfer from an EB surface. It's been a while (over a year) since I've tried it with an external source and it may be more stable at this time. If you are looking to ignite a mixture via this method, I'd be curious to hear how it works for you.

[RSuryaNarayan]

Thanks for your reply.

If I am not wrong, I should be filling in the appropriate n in the following line with the value of the heat flux in CGS units?:

PeleC/Source/External.cpp

Line 83 in 6749e57

Farr(i, j, k, n) = 0.0;

something like n==UTEMP`` then Farr(i, j, k, n) = some value

[drummerdoc]

You'd want to use n=UEDEN I believe

[RSuryaNarayan]

Thanks for the clarification!

[whitmanscu]

Basically, yes, although I believe you want to add to UEINT and UEDEN rather than UTEMP, for proper use in reactions and since temperature is then recomputed from internal energy. Whatever you add is effectively the S_ext term at the end of the RHS in the equations here: https://pelec.readthedocs.io/en/latest/Equations.html.

Also if it's not clear, you can use i, j, k in conjunction with the commented-out dx and prob_lo to specify where you want to apply the flux. It can also be time-varying, relative to the old and new states, etc. (with the new state typically being correct to use based on where the term is added in Advance.cpp.

[RSuryaNarayan]

yes it makes sense now. Similar to what we find in pc_initdata. Thanks a lot for the prompt replies. @whitmanscu and @drummerdoc !