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-   -   y+ and y* values in Fluent (https://www.cfd-online.com/Forums/fluent/95083-y-y-values-fluent.html)

HLYBoy December 5, 2011 17:39

y+ and y* values in Fluent
 
I've been running a nozzle case with a standard k-epsilon turbulence model and when I plot the y+ against the distance down the nozzle, the velus I get range from about 16-35. In the Fluent Theory Guide, it tells me to use a y* > 15 and I believe that y* and y+ are effectively the same.

But, I've now heard that I need a y+ of greater than 30 otherwise the errors get too large.

Does this mean my y+ values have been way too small?

Thanks in advance!

HLYBoy December 5, 2011 17:58

The Fluent Guide says that the range of y+ values for which wall functions are suitable depends on the Reynolds number, but the lower limit lies in the order of y* or about 15, so I went by that definition.


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