Different diffusivities

alberto · September 29, 2005, 15:29

Is it possible to set different diffusivities per each direction? I have to solve a scalar transport equation with a non-zero diffusion term in the X direction only.

Thanks in advance,
Alberto

hjasak · September 29, 2005, 16:46

That would be called tensorial diffucivity (viscosity), right - have a search. You will need to define the diffusivity (field) as a tensor.

Enjoy,

Hrv

ankgupta8um · February 27, 2006, 18:56

Hi,

I am solving for a passive scalar in the channelOodles case set-up. I would like to set the diffusivity of the passive scalar as some function of the passive scalar i.e. diffusivity will vary through out my computational domain. How can I specify that sort of diffusivity ?? It seems that this must be pretty straight forward but I am not able to figure out how??
Any help would be highly appreciated.

Thanks,
Ankur

hjasak · February 27, 2006, 19:15

Yes. Specify the viscosity as a volScalarField, set it to what you want and... that's it!

Enjoy,

Hrv

ankgupta8um · February 28, 2006, 02:47

Thanks Hrv..I was thinking on the same lines..
I looked at couple other postings on this board on the related issues and got a decent idea about it..

Thanks again.
-Ankur

September 29, 2005, 15:29	Is it possible to set differen	#1
alberto Senior Member Alberto Passalacqua Join Date: Mar 2009 Location: Ames, Iowa, United States Posts: 1,912 Rep Power: 36	Is it possible to set different diffusivities per each direction? I have to solve a scalar transport equation with a non-zero diffusion term in the X direction only. Thanks in advance, Alberto __________________ Alberto Passalacqua GeekoCFD - A free distribution based on openSUSE 64 bit with CFD tools, including OpenFOAM. Available as in both physical and virtual formats (current status: http://albertopassalacqua.com/?p=1541) OpenQBMM - An open-source implementation of quadrature-based moment methods. To obtain more accurate answers, please specify the version of OpenFOAM you are using.

September 29, 2005, 16:46	That would be called tensorial	#2
hjasak Senior Member Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,907 Rep Power: 33	That would be called tensorial diffucivity (viscosity), right - have a search. You will need to define the diffusivity (field) as a tensor. Enjoy, Hrv __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

February 27, 2006, 18:56	Hi, I am solving for a pas	#3
ankgupta8um Member Ankur Gupta Join Date: Mar 2009 Posts: 38 Rep Power: 17	Hi, I am solving for a passive scalar in the channelOodles case set-up. I would like to set the diffusivity of the passive scalar as some function of the passive scalar i.e. diffusivity will vary through out my computational domain. How can I specify that sort of diffusivity ?? It seems that this must be pretty straight forward but I am not able to figure out how?? Any help would be highly appreciated. Thanks, Ankur

February 27, 2006, 19:15	Yes. Specify the viscosity as	#4
hjasak Senior Member Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,907 Rep Power: 33	Yes. Specify the viscosity as a volScalarField, set it to what you want and... that's it! Enjoy, Hrv __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

February 28, 2006, 02:47	Thanks Hrv..I was thinking on	#5
ankgupta8um Member Ankur Gupta Join Date: Mar 2009 Posts: 38 Rep Power: 17	Thanks Hrv..I was thinking on the same lines.. I looked at couple other postings on this board on the related issues and got a decent idea about it.. Thanks again. -Ankur

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