Calculation of Gradient of a Tensor (Stress) in Cylindrical Coordinates in openFoam

alimea · September 19, 2018, 04:08

Hi all,

I need to calculate
d/dr(tau_rt) , d/dt(tau_tt)
where tau is stress tensor that is a volSymmTensorField and r , t are polar coordinates components.
I have two problem:
1- Foam doesn't have cylindrical coordinates
2- the function "fvc::grad(X)" can't get a volSymmTensorField as input.

Could you please help me if you have any similar experience?

EmadTandis · October 27, 2018, 04:01

Quote:

Originally Posted by alimea

Hi all,

I need to calculate
d/dr(tau_rt) , d/dt(tau_tt)
where tau is stress tensor that is a volSymmTensorField and r , t are polar coordinates components.
I have two problem:
1- Foam doesn't have cylindrical coordinates
2- the function "fvc::grad(X)" can't get a volSymmTensorField as input.

Could you please help me if you have any similar experience?

Hello
I have a same problem. Did you find any method to calculate fvc::grad(tensorField)?

alimea · October 27, 2018, 04:22

Quote:

Originally Posted by EmadTandis

Hello
I have a same problem. Did you find any method to calculate fvc::grad(tensorField)?

Hi
Unfortunately I didn't find any solution, however I defined some volScalarField for every component of stress tensor separately and then calculated the derivative of them.

EmadTandis · October 27, 2018, 08:20

Thanks Ali
I did ignore this term in my equation and in this way I solved the problem! But it shouldn't be that difficult to implement this function for tensorFields and I wondered when couldn't find it in OF.

roozbeh_s · February 7, 2021, 14:48

Quote:

Originally Posted by alimea

Hi
Unfortunately I didn't find any solution, however I defined some volScalarField for every component of stress tensor separately and then calculated the derivative of them.

Dear Alimea,
how did you do that. Could you share your procedure. Also, what did you do for boundaries?

HPE · February 7, 2021, 15:11

Maybe these help? (haven't used them):

https://github.com/OpenFOAM/OpenFOAM...ld/cylindrical

https://develop.openfoam.com/Develop...temTransform.H

roozbeh_s · February 7, 2021, 16:59

Quote:

Originally Posted by HPE

Maybe these help? (haven't used them):

https://github.com/OpenFOAM/OpenFOAM...ld/cylindrical

https://develop.openfoam.com/Develop...temTransform.H

Thanks so much. I skimmed through those, but they are used for transforming between Cartesian- and Cylindrical-coordinate systems. But I couldn't find the Gradient operator for the tensor field. Actually, my main concern is taking the gradient of volTensorField to solve the following equation:

div(grad(T)&&grad(T)),
and T is a second-order tensor.

September 19, 2018, 04:08	Calculation of Gradient of a Tensor (Stress) in Cylindrical Coordinates in openFoam	#1
alimea Senior Member A. Min Join Date: Mar 2015 Posts: 305 Rep Power: 12	Hi all, I need to calculate d/dr(tau_rt) , d/dt(tau_tt) where tau is stress tensor that is a volSymmTensorField and r , t are polar coordinates components. I have two problem: 1- Foam doesn't have cylindrical coordinates 2- the function "fvc::grad(X)" can't get a volSymmTensorField as input. Could you please help me if you have any similar experience?

February 7, 2021, 15:11		#6
HPE Senior Member Herpes Free Engineer Join Date: Sep 2019 Location: The Home Under The Ground with the Lost Boys Posts: 932 Rep Power: 12	Maybe these help? (haven't used them): https://github.com/OpenFOAM/OpenFOAM...ld/cylindrical https://develop.openfoam.com/Develop...temTransform.H __________________ The OpenFOAM community is the biggest contributor to OpenFOAM: User guide/Wiki-1/Wiki-2/Code guide/Code Wiki/Journal Nilsson/Guerrero/Holzinger/Holzmann/Nagy/Santos/Nozaki/Jasak/Primer Governance Bugs/Features: OpenFOAM (ESI-OpenCFD-Trademark) Bugs/Features: FOAM-Extend (Wikki-FSB) Bugs: OpenFOAM.org How to create a MWE New: Forkable OpenFOAM mirror

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October 27, 2018, 08:20		#4
EmadTandis Member Emad Tandis Join Date: Sep 2010 Posts: 77 Rep Power: 15	Thanks Ali I did ignore this term in my equation and in this way I solved the problem! But it shouldn't be that difficult to implement this function for tensorFields and I wondered when couldn't find it in OF.