Using calculated outlet values in another case by using mapFields

Imadori · August 14, 2013, 10:58

Hello everyone,
I know this must have been asked countless times, but as I'm quite new to openfoam and never really got the gist of it, I haven't been able to get my case working up until now, even after reading several threads and suggestions in these forums.

I'm trying to use the outlet, i.e. a fully developed velocity profile and other values, of a simple calculated case as an inlet of another one (on openfoam 1.7, turbulent flow at Re=200k) in order to reduce computational time. The use of mapFields seemed the easiest way to do so. However, I read that I had to use the directMapped boundary condition. My question is, how to do so? I somehow doubt that just renaming some patches in the "boundary" file from "patch" to "directMappedPatch" will work. Even so, would I have to rename just the inlet patch from the second case or the outlet from the first one as well?
I know it's much to ask, but if somebody had a brief step-by-step guide, I would be very happy to hear it.
Thanks a lot!

Bernhard · August 14, 2013, 11:27

I am not sure if your understanding of the directMappedPatch (mappedPatch in 2.x.x) is correct. With the directMappedPatch, you can not map the field of another case, but you map the field from the internal field of the present run to the inlet.

Is you inlet data transient or steady state?

cfdonline2mohsen · August 15, 2013, 06:21

Dear Ben
Have a look at the following post:
http://www.cfd-online.com/Forums/ope...-0-folder.html

Imadori · August 19, 2013, 11:25

Quote:

Originally Posted by Bernhard

I am not sure if your understanding of the directMappedPatch (mappedPatch in 2.x.x) is correct. With the directMappedPatch, you can not map the field of another case, but you map the field from the internal field of the present run to the inlet.

Is you inlet data transient or steady state?

My data is steady state.
So I can't connect two different cases with a directMappedPatch? I thought I read about that, hence my question. Here's an example of directMapped-usage, maybe I misunderstood something: http://http://www.cfd-online.com/Forums/openfoam/75434-mapping-boundary-conditions-another-case.html

Quote:

Originally Posted by cfdonline2mohsen

Dear Ben
Have a look at the following post:
http://www.cfd-online.com/Forums/ope...-0-folder.html

Thanks a lot, I will give it a try!
In my 0/U-file it says "value uniform (x x x)" at the inlet, though. I hope this won't pose a problem when simply replacing it with "value nonuniform List<vector>".

Bernhard · August 19, 2013, 11:30

If you read the posts in the linked thread, there is no mapping from another case going on, but from within the case, as I explained above.

If your data is steady state, then there is no need to do anything special, and you can give the non-uniform list as a boundary condition. This replacement should work. However, be sure to check the result, as the numbering of the face is pretty crucial.

August 14, 2013, 10:58	Using calculated outlet values in another case by using mapFields	#1
Imadori New Member hghfhg Join Date: Aug 2013 Posts: 2 Rep Power: 0	Hello everyone, I know this must have been asked countless times, but as I'm quite new to openfoam and never really got the gist of it, I haven't been able to get my case working up until now, even after reading several threads and suggestions in these forums. I'm trying to use the outlet, i.e. a fully developed velocity profile and other values, of a simple calculated case as an inlet of another one (on openfoam 1.7, turbulent flow at Re=200k) in order to reduce computational time. The use of mapFields seemed the easiest way to do so. However, I read that I had to use the directMapped boundary condition. My question is, how to do so? I somehow doubt that just renaming some patches in the "boundary" file from "patch" to "directMappedPatch" will work. Even so, would I have to rename just the inlet patch from the second case or the outlet from the first one as well? I know it's much to ask, but if somebody had a brief step-by-step guide, I would be very happy to hear it. Thanks a lot! bmikuz and ScarFace like this.

August 14, 2013, 11:27		#2
Bernhard Senior Member Bernhard Join Date: Sep 2009 Location: Delft Posts: 790 Rep Power: 21	I am not sure if your understanding of the directMappedPatch (mappedPatch in 2.x.x) is correct. With the directMappedPatch, you can not map the field of another case, but you map the field from the internal field of the present run to the inlet. Is you inlet data transient or steady state? ScarFace likes this.

August 15, 2013, 06:21		#3
cfdonline2mohsen Senior Member Mohsen KiaMansouri Join Date: Jan 2010 Location: CFD Lab Posts: 118 Rep Power: 16	Dear Ben Have a look at the following post: http://www.cfd-online.com/Forums/ope...-0-folder.html __________________ “If you have an apple and I have an apple and we exchange these apples then you and I will still each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas.”

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August 19, 2013, 11:30		#5
Bernhard Senior Member Bernhard Join Date: Sep 2009 Location: Delft Posts: 790 Rep Power: 21	If you read the posts in the linked thread, there is no mapping from another case going on, but from within the case, as I explained above. If your data is steady state, then there is no need to do anything special, and you can give the non-uniform list as a boundary condition. This replacement should work. However, be sure to check the result, as the numbering of the face is pretty crucial.