Question about standard k-e and low-re-ke

tstorm · September 23, 2009, 19:45

I'm using a UDF v2-f model. The v2-f model uses a different formulation for epsilon, but the same formulation for k as the k-e model.

As far as I can tell, the only difference between the k-e and low-re-ke models are the damping functions included in the epsilon transport equation. So my first question is, is that true?

If it's true, then why am I seeing different results for my v2-f model when I use the standard k-e model's k equation and the low-re-ke model's k equation?

ericnutsch · September 27, 2009, 23:19

Im no pro, but i figued you could use some input.

Damping ratio shouldnt change the end result, but it can...
It is possible that one of your solutions has found a "local min" for the residuals and has converged on a phantom solution as opposed to the desired solution.

I would try increasing the mesh resolution and attempt the model comparison again.

Best of Luck

September 23, 2009, 19:45	Question about standard k-e and low-re-ke	#1
tstorm Member Join Date: Apr 2009 Posts: 78 Rep Power: 17	I'm using a UDF v2-f model. The v2-f model uses a different formulation for epsilon, but the same formulation for k as the k-e model. As far as I can tell, the only difference between the k-e and low-re-ke models are the damping functions included in the epsilon transport equation. So my first question is, is that true? If it's true, then why am I seeing different results for my v2-f model when I use the standard k-e model's k equation and the low-re-ke model's k equation?

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September 27, 2009, 23:19		#2
ericnutsch Senior Member Eric Nutsch Join Date: Sep 2009 Location: Eugene, Oregon USA Posts: 113 Rep Power: 16	Im no pro, but i figued you could use some input. Damping ratio shouldnt change the end result, but it can... It is possible that one of your solutions has found a "local min" for the residuals and has converged on a phantom solution as opposed to the desired solution. I would try increasing the mesh resolution and attempt the model comparison again. Best of Luck