Integrate a 3D scalar over one direction

annan · March 1, 2024, 06:18

Hi folks,

I have a 3D distribution of my temperature obtained after an openfoam simulation, and I would like to visualize a surface distribution of the average temperature over the z direction only.

I have been trying to use programmable filters in paraview to do so, with no success. Can anybody help me achieve this please ?

Many thanks!

Severus · March 1, 2024, 10:08

Hello,
Unfortunately, I cannot help you do this in Paraview. As far as I know it is quite hard to do this in Paraview. I have tried doing it in the past but couldn't manage to write a properly working programmable filter for this purpose.

However I suggest you to use the columnAverage functionObject for this purpose (only available in ESI version). But you need to have a structured mesh
https://www.openfoam.com/documentati...volume%20field.

There are also some nice community contributions, for example see: https://github.com/syavash20/TurbLab...panwiseAverage

Good luck!

annan · March 13, 2024, 06:29

Hello Severus,

Thank you so much for your valuable response.

I have indeed tested columnAverage and it works perfectly since my mesh is structured. However, I wanted to use the same functionObject for temperature but the arithmetic average does not provide a satisfactory result. I think I need to integrate (U*T) in the z-direction, do you know any other functionObject that could help me compute this integral ?

Many thanks!

Severus · March 13, 2024, 13:19

Hello,
Lets say you compute U*T, now can you use columnAverage functionObject? Will your results be satisfactory? Or are you only looking for something to integrate a variable along a direction?

If your question is about how to compute U*T, you can look at codedFunctionObject, there are many posts out there regarding this.
https://www.openfoam.com/documentati...8H_source.html
Another option is define a new variable and simply multiply (U*T) inside your solver and recompile your solver.

If your question on integrating in a specific direction using a functionObject, sorry I am not aware of anything.

Thanks

March 1, 2024, 06:18	Integrate a 3D scalar over one direction	#1
annan Member annan Join Date: Nov 2016 Posts: 72 Rep Power: 9	Hi folks, I have a 3D distribution of my temperature obtained after an openfoam simulation, and I would like to visualize a surface distribution of the average temperature over the z direction only. I have been trying to use programmable filters in paraview to do so, with no success. Can anybody help me achieve this please ? Many thanks!

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March 1, 2024, 10:08		#2
Severus Member Shravan Join Date: Mar 2017 Posts: 60 Rep Power: 9	Hello, Unfortunately, I cannot help you do this in Paraview. As far as I know it is quite hard to do this in Paraview. I have tried doing it in the past but couldn't manage to write a properly working programmable filter for this purpose. However I suggest you to use the columnAverage functionObject for this purpose (only available in ESI version). But you need to have a structured mesh https://www.openfoam.com/documentati...volume%20field. There are also some nice community contributions, for example see: https://github.com/syavash20/TurbLab...panwiseAverage Good luck!

March 13, 2024, 06:29		#3
annan Member annan Join Date: Nov 2016 Posts: 72 Rep Power: 9	Hello Severus, Thank you so much for your valuable response. I have indeed tested columnAverage and it works perfectly since my mesh is structured. However, I wanted to use the same functionObject for temperature but the arithmetic average does not provide a satisfactory result. I think I need to integrate (U*T) in the z-direction, do you know any other functionObject that could help me compute this integral ? Many thanks!

March 13, 2024, 13:19		#4
Severus Member Shravan Join Date: Mar 2017 Posts: 60 Rep Power: 9	Hello, Lets say you compute UT, now can you use columnAverage functionObject? Will your results be satisfactory? Or are you only looking for something to integrate a variable along a direction? If your question is about how to compute UT, you can look at codedFunctionObject, there are many posts out there regarding this. https://www.openfoam.com/documentati...8H_source.html Another option is define a new variable and simply multiply (U*T) inside your solver and recompile your solver. If your question on integrating in a specific direction using a functionObject, sorry I am not aware of anything. Thanks