CFD-Post import data as variable

Benzouz · July 19, 2022, 08:47

Hi everyone,

I notice it is possible to export data from a variable as csv from CFD-Post, but I was wondering if it would be possible to do the same for importing data?

My goal would be to export a few variables, perform some calculations on them to create a new variable (using better tools than the expressions or macro available in CFD-Post), and then re-importing that variable into CFD-Post.

The reason for this is because I would like to perform some matrix calculations or use complex numbers, which are not possible in CFD-Post from what I found.

Thank you!

ghorrocks · July 19, 2022, 20:21

I do not know of a good way to do this. Your best bet would be to do it during the solver (maybe as a user fortran routine, it could even just read a text file) and write the result of that to a additional variable in the solver. Then it will be available in the post processor.

If you are doing advanced post processing like this you might want to consider more sophisticated post processors like tecplot, ensight or fieldview.

Opaque · July 20, 2022, 11:14

Quote:

Originally Posted by Benzouz

Hi everyone,

I notice it is possible to export data from a variable as csv from CFD-Post, but I was wondering if it would be possible to do the same for importing data?

My goal would be to export a few variables, perform some calculations on them to create a new variable (using better tools than the expressions or macro available in CFD-Post), and then re-importing that variable into CFD-Post.

The reason for this is because I would like to perform some matrix calculations or use complex numbers, which are not possible in CFD-Post from what I found.

Thank you!

How complex is your calculation than cannot be done using expressions? I guess you are writing an expression of some sort externally, correct?

Benzouz · August 2, 2022, 07:36

Thank you for your answers. I was away last week so I didn't get to reply earlier.

In the end I used the import command to load my csv:
>import type=Generic, filename=C:/file.csv

The thing is that I needed to check the Line and Face Connectivity when exporting the data otherwise I wouldn't be able to reload it properly after my calculation.

By the way by complex I meant the use of complex numbers, with real and imaginary parts, which I don't think CFD-post can handle.

ghorrocks · August 2, 2022, 08:26

While CFD-Post does not natively support complex number functions, you can write a complex number as two scalar variables and then define complex number functions from those two variables. Obviously this is not as nice as native functions but it could be worth considering to to avoid the hassle of exporting data and doing the function somewhere else.

July 19, 2022, 08:47	CFD-Post import data as variable	#1
Benzouz New Member Benjamin Join Date: Jul 2015 Posts: 21 Rep Power: 11	Hi everyone, I notice it is possible to export data from a variable as csv from CFD-Post, but I was wondering if it would be possible to do the same for importing data? My goal would be to export a few variables, perform some calculations on them to create a new variable (using better tools than the expressions or macro available in CFD-Post), and then re-importing that variable into CFD-Post. The reason for this is because I would like to perform some matrix calculations or use complex numbers, which are not possible in CFD-Post from what I found. Thank you!

July 19, 2022, 20:21		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	I do not know of a good way to do this. Your best bet would be to do it during the solver (maybe as a user fortran routine, it could even just read a text file) and write the result of that to a additional variable in the solver. Then it will be available in the post processor. If you are doing advanced post processing like this you might want to consider more sophisticated post processors like tecplot, ensight or fieldview. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

August 2, 2022, 08:26		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	While CFD-Post does not natively support complex number functions, you can write a complex number as two scalar variables and then define complex number functions from those two variables. Obviously this is not as nice as native functions but it could be worth considering to to avoid the hassle of exporting data and doing the function somewhere else. Benzouz likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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August 2, 2022, 07:36		#4
Benzouz New Member Benjamin Join Date: Jul 2015 Posts: 21 Rep Power: 11	Thank you for your answers. I was away last week so I didn't get to reply earlier. In the end I used the import command to load my csv: >import type=Generic, filename=C:/file.csv The thing is that I needed to check the Line and Face Connectivity when exporting the data otherwise I wouldn't be able to reload it properly after my calculation. By the way by complex I meant the use of complex numbers, with real and imaginary parts, which I don't think CFD-post can handle.