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-   -   Turbulence Model in axisymmetric nozzle simulation (https://www.cfd-online.com/Forums/fluent/118093-turbulence-model-axisymmetric-nozzle-simulation.html)

cric92 May 21, 2013 02:03

Turbulence Model in axisymmetric nozzle simulation
 
Hi

I am simulating an axisymmetric nozzle. I have an issue with which turbulence model to use. Currently I am using standard K-epsilon and i am not getting any shock wave inside the nozzle. When I switch to SST K omega i get shock wave in the flow.

I would like to ask which is the recommended turbulence model for these type of flow

oj.bulmer May 21, 2013 05:27

By intuition, std k-eps model is diffusive and hence may smear out the sharp gradients responsible for shocks. Have you tried realizable model? It is deemed to be good in modelling jets.

OJ

cric92 May 22, 2013 11:50

Yes, Just tried realizable.. it also shows a shock wave

NozzleNoobie September 4, 2017 12:11

Hi, could i ask you what do you mean by diffusive?

Arjun_kalkur September 4, 2017 16:57

K-epsilon does not behave well in large pressure gradient, one like shocks, I'd suggest to stick with SST. By diffusive he means the behavior of the solver, like for eg:- Picks the information from the succeeding nodes and moves forward

NozzleNoobie September 4, 2017 23:35

I see that the SST k-omega model is more suitable for compressible flow into a nozzle for its good behaviour in adverse pressure gradients (shock) and separating flow. Thank you for your help!


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