Learning Forum

[Sky0101]

Hello, everyone!

ANSYS Fluent Theory Guide provides theoretical information about several k-epsilon models except low reynold turbulent models.

In standard k-e turbulent model, the generation of turbulence due to buoyancy are solved by the fomula bellow.

My question is how fluent to calculate the generation of turbulence due to buoyancy in low reynold turbulent model.

[Amine Ben Hadj Ali]

Can you explain more? Which Low-Re turbulence model are you now talking about? The formula you shared is related to TKE prodoution or destruction due to temperature gradients / density variation due to temperature variations.

[Sky0101]

Hi, Amine. Thanks for your reply again!

There are 6 low reynold turbulence models in fluent. It's better to make all of them clear,espacially AKN.

I focus on the formula over the red line, which snipped from TKE transport equation contained in standard k-e modles.

It's a part of TKE production generated by buoyancy effect.In my question, density is a function of tempurature and pressure. Accurately, I use NIST real gas modle to calculate properties.

[Rob]

Those models were added into an old version of Fluent (probably v5) and never removed for various reasons. I don't think anyone has used them in at least 10 years so I'd be VERY wary about using them. 

 

From the current DOC

low-re-ke-index

Specifies which low-Reynolds-number - model is to be used. Six models are available:

Index Model

0       Abid

1      Lam-Bremhorst

2      Launder-Sharma

3      Yang-Shih

4      Abe-Kondoh-Nagano

5      Chang-Hsieh-Chen

 

This paper has 3 of the models referenced  www.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS1877705815002829%2Fpdf%3Fmd5%3D0ca7d39ece6f9752648cc38ec38525d8%26pid%3D1-s2.0-S1877705815002829-main.pdf&usg=AOvVaw1vPGerRi3If05SrBguS01J   including AKN.