automap and rmap in OpenFOAM boundaries

trailer · December 24, 2021, 08:52

Hello to all,

I have tried to get information on the automap and rmap function in OF to no avail.

I see that boundaries that create fields use them (e.g., prghPressure, totalPressure, totalTemperature) while others do not e.g., swirlFanVelocity/fixedMean/flowRateInletVelocity (although fields are created in the calculation)

I would like to know, what they are used for and when do I need to define them. Do they impact the calculations?

rmap appears to be used when reconstructing the fields, automap I do not know.

PS: Sorry for putting the post here. It should be in the programming session

hjasak · December 25, 2021, 14:23

They are needed for decomposePar, reconstructPar, topological changes and load balancing: in fact every time the mesh dynamically changes during the run.

One of mine,

Hrv

trailer · December 25, 2021, 16:49

Hello prof. Jasak,

Thank you for the reply.

If you would be so kind, a follow up question.

If one is writing a Dirichlet boundary condition for a static case without collecting field (scalar, vector and tensor) information from the variable files, the default (in fvPatchField) automap and rmap can be used, which is why there is no redefinition of automap and rmap in e.g., parabolicVelocity.

Is this correct?

Can you give me a tutorial example where the automap function is being used?

XJ_Wang · March 27, 2023, 02:13

Quote:

Originally Posted by trailer

Hello prof. Jasak,

Thank you for the reply.

If you would be so kind, a follow up question.

If one is writing a Dirichlet boundary condition for a static case without collecting field (scalar, vector and tensor) information from the variable files, the default (in fvPatchField) automap and rmap can be used, which is why there is no redefinition of automap and rmap in e.g., parabolicVelocity.

Is this correct?

Can you give me a tutorial example where the automap function is being used?

Hi Trailer

Have you found some references for this?

Best
Xiangjie

trailer · March 28, 2023, 05:08

Quote:

Originally Posted by XJ_Wang

Hi Trailer

Have you found some references for this?

Best
Xiangjie

Hi Xiangjie,

Unfortunatly, no.

If you came across it, please let me know!

XJ_Wang · March 29, 2023, 12:18

Hi Trailer,

Here is my personal understanding:

autoMap and rmap are used for parallel computing but they are not always needed. As you have mentioned, the parabolic velocity library(which is very popular in the tutorials) does not use these two functions, that is because there is no parameters needed to be decomposed. For example, when using DFSEM from OpenFOAM.com, the R, L values need to be decomposed because they are tensorField or scalarField type data. If there is no this kind of data/parameters, you don't need to use these two functions.

December 24, 2021, 08:52	automap and rmap in OpenFOAM boundaries	#1
trailer Member Join Date: Mar 2021 Posts: 39 Rep Power: 5	Hello to all, I have tried to get information on the automap and rmap function in OF to no avail. I see that boundaries that create fields use them (e.g., prghPressure, totalPressure, totalTemperature) while others do not e.g., swirlFanVelocity/fixedMean/flowRateInletVelocity (although fields are created in the calculation) I would like to know, what they are used for and when do I need to define them. Do they impact the calculations? rmap appears to be used when reconstructing the fields, automap I do not know. PS: Sorry for putting the post here. It should be in the programming session Last edited by trailer; December 24, 2021 at 11:12.

December 25, 2021, 14:23		#2
hjasak Senior Member Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,907 Rep Power: 33	They are needed for decomposePar, reconstructPar, topological changes and load balancing: in fact every time the mesh dynamically changes during the run. One of mine, Hrv __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

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December 25, 2021, 16:49		#3
trailer Member Join Date: Mar 2021 Posts: 39 Rep Power: 5	Hello prof. Jasak, Thank you for the reply. If you would be so kind, a follow up question. If one is writing a Dirichlet boundary condition for a static case without collecting field (scalar, vector and tensor) information from the variable files, the default (in fvPatchField) automap and rmap can be used, which is why there is no redefinition of automap and rmap in e.g., parabolicVelocity. Is this correct? Can you give me a tutorial example where the automap function is being used?

March 29, 2023, 12:18		#6
XJ_Wang New Member Xiangjie Wang Join Date: Jul 2019 Posts: 26 Rep Power: 7	Hi Trailer, Here is my personal understanding: autoMap and rmap are used for parallel computing but they are not always needed. As you have mentioned, the parabolic velocity library(which is very popular in the tutorials) does not use these two functions, that is because there is no parameters needed to be decomposed. For example, when using DFSEM from OpenFOAM.com, the R, L values need to be decomposed because they are tensorField or scalarField type data. If there is no this kind of data/parameters, you don't need to use these two functions.