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-   -   is this y plus value is right? (https://www.cfd-online.com/Forums/cfx/21926-y-plus-value-right.html)

santhil December 10, 2005 05:12

is this y plus value is right?
 
Hi to all.I have done analysis of a pressure vessel.Now when i am visulizing in cfx post i am getting y plus at some location too higher.It is upto 28 to 2800 in range.so this is right or not.i.e. my will it effect the results?Can anybody please tell me that this is right or not?I have read in manual that its value can be controlled by scalable wall function.so suppose i want to reduce y plus then can i do like this i.e. use of scalable wall function.also tell me that what should be general limit of y plus? thanks to all.

TB December 10, 2005 10:28

Re: is this y plus value is right?
 
What turb model are you using? For low Re model, Y+ is generally less than 2. If wall function is used, Y+ is normally 30~150. If high Y+ value is not in the domain of interest, it may be okay. Refine your near wall mesh & see if results will change dramatically.

santhil December 11, 2005 08:04

Re: is this y plus value is right?
 
I am using k E model Re is around 4000 t 5000.how i can refine mes hin near wall region.i.e. by using prism mesh or not? or should i reduce elem length? thanks for ur efforts.

TB December 11, 2005 20:30

Re: is this y plus value is right?
 
What type of mesh are you using? If it's tet mesh, then I will try to reduce the first layer height by a factor of 3~5, rerun the simulation for about 50-100 steps & check the Yplus again in Post.


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