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-   -   Specifying the transition Reynolds and cfx's calculation of this number (https://www.cfd-online.com/Forums/cfx/86833-specifying-transition-reynolds-cfxs-calculation-number.html)

Nick R April 3, 2011 23:10

Specifying the transition Reynolds and cfx's calculation of this number
 
Hi,

My question is regarding the way the transition Reynolds number should be specified as a user defined parameter in the transition models. I read in other posts that the method CFX uses to define the length scale is thru the cube of the flow domain volume and averaged velocities. So I wonder how I can come up with a Re that is consistent with this method?

Suppose I estimate transition to occur at 1/5th of the chord on an airfoil from the leading edge. Should I simply use this length to calculate and specify Reynolds in the CFX model?

Regards,
Nick

ghorrocks April 4, 2011 20:27

You can specify the transition location by many ways. Not sure if you can specify a Re number, hopefully you can.

But if you know where the transition is you can just define the intermittency and define this area as laminar and that area as turbulent. Much simpler.

vidhya April 5, 2011 02:49

hi, i am doing simulation of multiphase flows in stirred tanks using gas-liquid.. the problem is well defined but i get some solver errors.. POPDIR, MEMER, MAKDIR.. it says some files in the crash recovery file is locked.. how to get rid of this problem?

delaneyluke April 7, 2011 03:31

Post some more details of the error from the .out file Vidhya. The error could be numerous things. And please start a new thread as the topic of this thread has no relation to your problem.

Regards
Luke


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