perturbU utility for non-Newtonian flow

nskelly · February 1, 2021, 07:36

Hi,

I have been working on Newtonian turbulent channel flow, by means of DNS, with some success. However, I am interested in non-Newtonian turbulent channel flow now, but I am having some difficulties in triggering transition to turbulence.

For the Newtonian cases, I had used perturbU utility to introduce streaks to a turbulent velocity profile, which then develops into a nice turbulent flow field.

However, when I do this with a non-Newtonian case, the perturbations die out.

I'm curious whether anyone else has tried a turbulent non-Newtonian flow simulation using perturbU, and encountered the problems I have.

Thanks.

sadsid · February 9, 2021, 16:07

I do not know about your issue, however, if possible then please let me about Newtonian DNS case. Have you obtained the comparison with benchmark solutions. I am trying this case but my solutions do not converge.

sadsid · February 9, 2021, 16:15

By the way, can you share your perturbU. I think there is some problem with your perturbU.

HPE · February 9, 2021, 16:51

I wouldn't use OpenFOAM for DNS in the first place, honestly - OpenFOAM should be very slow for DNS. Academic software such as http://channelflow.org/ should be a much better alternative.

sadsid · February 10, 2021, 10:37

Yes, OF is expensive. I know some in-house codes are available for DNS channel flow case and can be used for getting the benchmark solutions.

But just for learning, I was doing it with OF.

February 1, 2021, 07:36	perturbU utility for non-Newtonian flow	#1
nskelly Member Nat K Join Date: Oct 2017 Posts: 68 Rep Power: 8	Hi, I have been working on Newtonian turbulent channel flow, by means of DNS, with some success. However, I am interested in non-Newtonian turbulent channel flow now, but I am having some difficulties in triggering transition to turbulence. For the Newtonian cases, I had used perturbU utility to introduce streaks to a turbulent velocity profile, which then develops into a nice turbulent flow field. However, when I do this with a non-Newtonian case, the perturbations die out. I'm curious whether anyone else has tried a turbulent non-Newtonian flow simulation using perturbU, and encountered the problems I have. Thanks.

February 9, 2021, 16:51		#4
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	I wouldn't use OpenFOAM for DNS in the first place, honestly - OpenFOAM should be very slow for DNS. Academic software such as http://channelflow.org/ should be a much better alternative. __________________ 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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February 9, 2021, 16:07		#2
sadsid Member Join Date: Jan 2017 Posts: 71 Rep Power: 9	I do not know about your issue, however, if possible then please let me about Newtonian DNS case. Have you obtained the comparison with benchmark solutions. I am trying this case but my solutions do not converge.

February 9, 2021, 16:15		#3
sadsid Member Join Date: Jan 2017 Posts: 71 Rep Power: 9	By the way, can you share your perturbU. I think there is some problem with your perturbU.

February 10, 2021, 10:37		#5
sadsid Member Join Date: Jan 2017 Posts: 71 Rep Power: 9	Yes, OF is expensive. I know some in-house codes are available for DNS channel flow case and can be used for getting the benchmark solutions. But just for learning, I was doing it with OF.