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August 11, 2015, 01:08 |
Difference in turbulence model
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#1 |
New Member
Sam
Join Date: Dec 2012
Posts: 9
Rep Power: 13 |
Hi Guys,
I am solving for flow analysis in waterjacket in IC engine. I am studying, "effect of different turbulence model on flow physics in waterjacket". I have simulated this with Std ke, RNG k-epsilon and EARSM k-epsilon turbulence model. Results with the EARSM model is close to the baseline results. My question is whether is it recommended to use EARSM over std ke? what are the advantages and disadvantages of EARSM over other two turbulence model. Why this model is not so popular if it accounts for the secondary flow? Thanks in advance ! |
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August 11, 2015, 05:08 |
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#2 | |||
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
Quote:
Quote:
* Can capture secondary flows * Can capture the effect of streamline curvature Disadvantages: * Often is MUCH harder to converge * Additional variables and simulation time and memory requirements * For flows which do not have secondary flows or streamline curvature it adds no additional benefit * It introduces new empirical constants for tuning which in some flows makes it less accurate than the simpler SST model. Quote:
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August 12, 2015, 02:23 |
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#3 |
New Member
Sam
Join Date: Dec 2012
Posts: 9
Rep Power: 13 |
Thanks Glenn for information.
Well, the problem with SST is that the mesh count is more than double compared to k-epsilon. Also, simulation time is much higher for SST. Results of k-epsillon are in good agreement with SST values, infact the results of pressure drop and mass flow of EARSM model are more close to SST results compared to std ke and RNG ke. You said in disadvantages of EARSM, " in some flows it is less accurate" Can you put light on which flow you were talking? |
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August 12, 2015, 05:50 |
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#4 | |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
Quote:
I cannot quote exactly which flow EARSM is less accurate. I have come across several examples over the years. I would expect it to have difficulties in things like boundary layer growth, bluff body flows and things like that. k-eps and SST are more suitable in those situations for most applications. |
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