Collecting turbulent statistics with openFOAM

manuc · May 4, 2017, 07:37

Hello All

I have a geometry with:
Spheres packed in a solid box. Flow of fluid through the pore space. The flow is induced by buoyancy effects. There exists a heat transfer between the fluid and the solid spheres.

Its a conjugate heat transfer problem.
I would like to collect turbulent statistics of 1st order and higher like :

1. Kinetic energy
2.Reynolds stress
3.turbulent heat flux (u'T')
4.temperature variance (T'T')
5.gradient of the above quantities etc.

along a 2d slice in my 3d domain during runtime.

(I am only aware of fieldAverage where I could save the whole field)
Is it possible using function objects to save the data along the plane.
Also should i create new fields like grad(uT) in createfields.H for both solid and fluid to obtain them using any function (what I am looking for) to save data over a plane.

Luttappy · March 28, 2018, 13:44

Hi Manu
There is a post processing utility called cuttingPlane to extract the data (U, p etc) of selected slice/plane in a three dimensional geometry during the simulation.
I think there should be an option to write turbulent statistics as well.
Please go through the following examples in the tutorials, you may get some idea

1. simpleFoam/motorBike
2. pisoFoam/les/motorBike/
3. pimpleDyMFoam/movingCone

Bloerb · March 29, 2018, 03:37

Depending on your mesh there are several options. The best solution would be a faceZone. This however requires your mesh to match the plane you are trying to evaluate. What you are looking for is the surfaceFieldValue function object.
(Github Link). This can be used with a patch | faceZone | or a sampledSurface. The sampledSurface could e.g be provided via an stl file. The result can be saved to a vtk file for postProcessing in paraview.

You should be able to calculate some of those via function objects as well.

May 4, 2017, 07:37	Collecting turbulent statistics with openFOAM	#1
manuc Senior Member Manu Chakkingal Join Date: Feb 2016 Location: Delft, Netherlands Posts: 129 Rep Power: 10	Hello All I have a geometry with: Spheres packed in a solid box. Flow of fluid through the pore space. The flow is induced by buoyancy effects. There exists a heat transfer between the fluid and the solid spheres. Its a conjugate heat transfer problem. I would like to collect turbulent statistics of 1st order and higher like : 1. Kinetic energy 2.Reynolds stress 3.turbulent heat flux (u'T') 4.temperature variance (T'T') 5.gradient of the above quantities etc. along a 2d slice in my 3d domain during runtime. (I am only aware of fieldAverage where I could save the whole field) Is it possible using function objects to save the data along the plane. Also should i create new fields like grad(uT) in createfields.H for both solid and fluid to obtain them using any function (what I am looking for) to save data over a plane. __________________ Regards Manu

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March 28, 2018, 13:44		#2
Luttappy Member HK Join Date: Oct 2015 Location: Madras Posts: 31 Rep Power: 10	Hi Manu There is a post processing utility called cuttingPlane to extract the data (U, p etc) of selected slice/plane in a three dimensional geometry during the simulation. I think there should be an option to write turbulent statistics as well. Please go through the following examples in the tutorials, you may get some idea 1. simpleFoam/motorBike 2. pisoFoam/les/motorBike/ 3. pimpleDyMFoam/movingCone

March 29, 2018, 03:37		#3
Bloerb Senior Member Join Date: Sep 2013 Posts: 353 Rep Power: 20	Depending on your mesh there are several options. The best solution would be a faceZone. This however requires your mesh to match the plane you are trying to evaluate. What you are looking for is the surfaceFieldValue function object. (Github Link). This can be used with a patch \| faceZone \| or a sampledSurface. The sampledSurface could e.g be provided via an stl file. The result can be saved to a vtk file for postProcessing in paraview. You should be able to calculate some of those via function objects as well.