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October 22, 2021 at 10:34 am
Emma CFD
SubscriberHello!
I want to modify the DRW model by changing the normal velocity fluctuations. I run the simulations by using the v²-f turbulence model, the next step is to import the obtained fluctuations by the v²-f model and implement it at the DRW based on the equation below: kmodified= 3v²/2 for y+ < 30
I need to create a UDF for that. I don't have any idea what macro should I use and also where exactly I can change the fluctuating velocities.
Any help!
Thank you!
Regards.
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October 22, 2021 at 1:53 pm
Rob
Forum ModeratorHaving read through the theory I'm not sure it's even as easy as that! You might be better looking at not using the built in DRW but instead providing a body force to a particle based on the same maths taking data from v2f etc.
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October 28, 2021 at 12:05 pm
Emma CFD
SubscriberThank you sir for the reply!
I really don't know where to begin, where to access the normal fluctuation velocities? is it in the time scale used in the DRW model? if yes which command I need to use?
sorry for my questions but I really feel stuck and I need help!
Regards.
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October 28, 2021 at 3:50 pm
Rob
Forum ModeratorCheck the maths, do you need to infer them from the k and other terms? We're heading out of what we (staff) can cover on here so will need to rely on the wider community.
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May 4, 2022 at 4:54 pm
sreekesh
Subscriberyes. Basically Random Walk Model calculate the instantaneous fluctuating velocity from RMS turbulent velocity fluctuations and Turbulent kinetic energy with use of a Gaussian random number with zero mean and unit variance.
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November 15, 2022 at 2:32 pm
Shuvo Chowdhury
SubscriberHello ! Did you get any solution? I am stuck at the same problem.
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