Hello,

Can any body please help me how to model low reynolds number K-E Turbulent Model in Fluent because the defalt K-E Turbulent Model used by Fluent is not valid for Low raynolds number flow. Thanks for your valuable suggestion

I am having same question in my mind. Can you just tell me, Re number u are having in your problem.

A Low Reynolds number model is a turbulence model that integrates through the viscous sub-layer down to the wall (i.e. the locally low Reynolds number region of the flow). It is still only applicable to high Reynolds number flows where the flow is fully turbulent. It is not a model for solving flows with low global Reynolds number. For that you need a transition model and I don't think that a good universal transition model exists.

There is the low Re model in Fluent. Activate it through the text interface at:

/define/models/viscous/turbulence-expert low-re-ke yes

Greg

There are six models available through text command:

define/models/viscous/low-re-ke-index

Index: 0...Abid

1...Lam-Bremhorst

2...Launder-Sharma

3...Yang-Shih

4...Abe-Kondoh-Nagano

5...Chang-Hsieh-Chen

Fluent uses number 3 as default.

[gmwsy]

Originally Posted by Greg Perkins
;101560

There is the low Re model in Fluent. Activate it through the text interface at:

/define/models/viscous/turbulence-expert low-re-ke yes

Greg

Hi~ Greg:

Very good information. Thank you!

But it seems that the range of low Re has never been mentioned in the Fluent mannual. Do you know what range of Re can be classified into low Re in Fluent?
Thanks a lot.

[shg74]

Hi Greg,

I tried several times the text command, but gives me "invalid command". Can you help me?

[atturh]

/define/models/viscous/turbulence-expert/low-re-ke yes

there is a "/" between turbulence-expert and low-re-ke yes.

this should get u to the command

[shg74]

It works but just for one of the mentioned turbulence models

[sona]

Hi Greg

Really good information.Thanks alot.
Is Lai and So model also available in Fluent?...

[kbaker]

before you select low RE k-e model from text command you need first to choose standard k-e from the menu define>model> viscus else you cannot see the low RE k-e model in text command.

[sona]

Hi Kbaker

Thanks for your reply.


I tried the following command after selecting define/models/viscous/k-epsilon standard,

/define/models/viscous/turbulence-expert> low-re-ke
Enable the low-Re k-epsilon turbulence model? [yes] yes

/define/models/viscous/turbulence-expert> low-re-ke-index

but it is not showing the available Low Re models.
Hope you can help me.

[samcfd]

There are six models available through text command:

define/models/viscous/low-re-ke-index

Index: 0...Abid

1...Lam-Bremhorst

2...Launder-Sharma

3...Yang-Shih

4...Abe-Kondoh-Nagano

5...Chang-Hsieh-Chen

Fluent uses number 3 as default.


I was given in one of the posts that the above low re k-e models are available in FLUENT. Can someone pls from where these models came from. WHich book or material describes its significance in FLUENT

[vincenzo]

Hello everyone. Can anybody point me how to turn on the low-re-ke turbulence model in Fluent 14?

In the text user interface there is no such position in /define/models/viscous/turbulence-expert. If I enter 'help' there is a note that says: "These followed by "*" are currently disabled" and below there is among others low-re-ke followed by "*".

How to turn it on? Is it possible? Thanks.

[Mohamed Refaat]

I'm trying to improve my simulation using non-linear turbulence models such as the modified k-epsilon model of craft et al. 1996

Please, is there nonlinear turbulence models built in fluent that can be activated using the same manner as low Re model?

Thanks in advance

[The_seeker]

Hi All
I was trying to implement low-reynolds number in fluent. I was successful in doing so. Just to be sure, I tried o search these models in fluent manual but could not find them. Are the index numbers mentioned in on eof the above posts still same for the latest version of FLUENT? Contrary to what is mentioned in previous posts, the default index which appears in FLUENT is 0, not 3. So I just wanted to assure.

[AlexanderZ]

typedef enum
{
  ABID              = 0,
  LAM_BREMHORST     = 1,
  LAUNDER_SHARMA    = 2,
  YANG_SHIH         = 3,
  ABE_KONDOH_NAGANO = 4,
  CHANG_HSIEH_CHEN  = 5,
  PEROT             = 6
} Low_Re_Model_Type;

by default fluent uses 0 (ABID)

[The_seeker]

Thank you very much Alexander for your response. May I know where did you find the above? Do you type something in the TUI to get this?

[AlexanderZ]

your folder...\ANSYS Inc\v192\fluent\fluent19.2.0\src\turbulence

turb.h file

[The_seeker]

Thanks a lot.