Using randomise field function for turbulent channel flow

sourav0921 · December 20, 2018, 05:54

Hi

I am using randomise field function to give random perturbation over mean velocity considering parabolic mean velocity profile initially. But instead of adding to the mean velocity profile and generating instantaneous velocity profile it comes as a seperate file Urandom instead of U in the 0 folder. I am using OPENFOAM V6 with gcc compiler 4:7.3.0. Can anyone kindly tell me is this bug or some mistake in the procedure?

fumiya · December 26, 2018, 16:55

I think Urandom = U + random perturbations.
You can use the Urandom field as an initial velocity field by renaming it.

Best regards,
Fumiya

sourav0921 · December 27, 2018, 01:16

Hi Fumiya,
Thanks for your suggestion.I will do the same. But can you tell me as the other field functions automatically updates after specified time step then why it won't able to?

December 20, 2018, 05:54	Using randomise field function for turbulent channel flow	#1
sourav0921 New Member SOURAV GANGULI Join Date: Dec 2018 Posts: 11 Rep Power: 8	Hi I am using randomise field function to give random perturbation over mean velocity considering parabolic mean velocity profile initially. But instead of adding to the mean velocity profile and generating instantaneous velocity profile it comes as a seperate file Urandom instead of U in the 0 folder. I am using OPENFOAM V6 with gcc compiler 4:7.3.0. Can anyone kindly tell me is this bug or some mistake in the procedure?

December 26, 2018, 16:55		#2
fumiya Senior Member Fumiya Nozaki Join Date: Jun 2010 Location: Yokohama, Japan Posts: 266 Blog Entries: 1 Rep Power: 19	I think Urandom = U + random perturbations. You can use the Urandom field as an initial velocity field by renaming it. Best regards, Fumiya __________________ [Personal] Blog: https://caefn.com/ Twitter: https://twitter.com/FumiyaNozaki SlideShare: http://www.slideshare.net/fumiyanozaki96

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December 27, 2018, 01:16		#3
sourav0921 New Member SOURAV GANGULI Join Date: Dec 2018 Posts: 11 Rep Power: 8	Hi Fumiya, Thanks for your suggestion.I will do the same. But can you tell me as the other field functions automatically updates after specified time step then why it won't able to?