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-   -   Rotational flow turbulence model (http://www.cfd-online.com/Forums/openfoam-solving/58009-rotational-flow-turbulence-model.html)

ntrask February 2, 2009 12:16

Hello all, Can anyone pleas
 
Hello all,

Can anyone please tell me whether one of the RANS turbulence models takes into account the effects of rotation? I'm looking to apply this to a high Reynolds number, swirling jet.

Alternatively, if anybody could point me toward a reference/thread describing what regimes the included turbulence models are built for I would be very appreciative. I've had limited success searching the forums and reading the code.

-Nat

gwierink February 3, 2009 04:30

Hi Nat, The RANS k-epsilon
 
Hi Nat,

The RANS k-epsilon model is not the best choice for flows with strong rotation, shear, and/or confined flows. This is due to the way of averaging and assumptions on the isotropy of turbulence. It is not a shortcoming of OpenFOAM, but it is because of the turbulence modelling. In fact, in OpenFOAM you have the possibility to change the solver so that it will fit your case http://www.cfd-online.com/OpenFOAM_D...part/happy.gif. Anyway, if you have the possibility I would try one of the LES solvers for your problem. You can find details on k-epsilon on many websites, e.g. this one: http://www.google.fi/url?sa=t&source=web&ct=res&cd=2&url=http%3A%2F%2Fc fd.me.umi st.ac.uk%2Ftmcfd%2Fpdfs%2Ffile_pdf-1023456176.pdf&ei=kguISamTLZiq-gaA0v3VBw&usg= AFQjCNHUcHvKTzgxxxyMj89mEtm4vMIREw&sig2=Kw7XRAIrXj REhEqWAmGZlw. The OpenFOAM user guide lists some general guidelines for the solvers on p. U-83 and onwards and there is a solver tutorial in 3.2.4 on p. U-74.

Regards, Gijsbert

billy February 3, 2009 04:55

Maybe a Reynolds stress turbul
 
Maybe a Reynolds stress turbulence model or DNS (just kidding).

ntrask February 3, 2009 10:59

Thanks for the quick replies.
 
Thanks for the quick replies. Unfortunately, my turbulence model is also coupled to a subgrid atomization model based off the Reynold's decomposition assumptions, so an LES won't work (I need the turbulent kinetic energy, not just the sub-grid kinetic energy). I know that the stand kEpsilon models included in Foam won't work for anisotropic flows, but when I look into the other models (especially the ones included in rasInterfoam) they all seem to be tailored to low Re number flows.

I'd even be interested in implementing a turbulence model and submitting it to the next release, if someone can suggest a model not currently in the code.


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