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Y plus for a fuel rod bundle.

Posted: Thu Apr 04, 2019 1:09 pm
by meb15aa
Hi again everyone,
I would just like some clarification on something. I am working on a fuel bundle, and I am unsure if I calculated my y plus value correctly. I used an online Y plus calculator that my peers advised me to use.
http://www.pointwise.com/yplus/

https://www.nuclear-power.net/nuclear-e ... iameter-2/

In regards to the reference length, when looking through code saturne documents it talked about the hydraulic diameter.

https://www.code-saturne.org/cms/sites/ ... e-Wall.pdf

https://www.nuclear-power.net/nuclear-e ... iameter-2/

I used this value as the reference length for calculating my y plus. Is this correct?

Re: Y plus for a fuel rod bundle.

Posted: Thu Apr 04, 2019 4:46 pm
by Antech
Hello.
This reference length is an approximate boundary layer length (I believe, in streamwise direction). It' doesn't affect required first cell height much so it's not critical. Just check the Y+ after the calculation and ensure that it doesn't exceed 2...3 in the area of interest and that it's not too low (like 0.1 or lower).