Shock induced Seperation
Shock induced Seperation
(OP)
Anybody had any experience of predicting seperation due to a shock. We know it is wrong as our prediction does not line up with our experiment, but are struggling to find a method to correctly predict this phenomenon.
we are using fluent , with standard K-e , 2nd order discretization.
we are using fluent , with standard K-e , 2nd order discretization.





RE: Shock induced Seperation
RE: Shock induced Seperation
RE: Shock induced Seperation
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**[Menter, F. R. (1993) "Zonal Two Equation k-? Turbulence Models for Aerodynamic Flows," AIAA Paper 93-2906; Mani, M., Ladd, J. A., Cain, A. B., and Bush, R. H.(1997) "An Assessment of One- and Two-Equation Turbulence Models for Internal and External Flows," AIAA Paper 97-2010]
RE: Shock induced Seperation
Certainly adapting the grid will be another area of investigation , but I have 100K cells in the region that contains the shock with a good BL mesh as well, (all hex).
I will check out the validation case as well, thats a very good link I was not aware of that. Bit baffled as to the boundary conditons as the pressure ratio is very much below the critical ratio, but I'm sure it will become clear as I look into it, anyhow the grid file supplied has imported into gambit nicely which is an all time first !
RE: Shock induced Seperation
Note that none of the models appears to do a good job of predicting both seperation and/or re-attachment accurately.
Do you have access to the source code for Fluent, so that you could try coding in some of the corrections mentioned in the NPARC/Wind papers? Alternatively, do you have a job in the U.S., for a US company? If so, you can ask for copy of the NPARC and Wind codes. It costs a nominal amount ($50? IIRC) for the distribution/mailing/handling fee, but you get the source code. Which of course, means you need a compiler. The coolest thing about Wind and NPARC are their ability to run on a Beowulf cluster (parallel processing "supercomputer" network, running Linux).
Good luck with your task. Would love to hear if Fluent can do as well or better than Wind at the validation problem.