Hydraulic diameter and turbulence parameter

[lehongduc]

Hello,

I have a newbie question about the hydraulic diameter that we choose for the turbulence parameter of the Inlet. I'm using CSv4.0 to simulate a gas flow exiting a pipeline into the air. I use k-epsilon model for the gas turbulence. I can give the initial value for the k and epsilon or I can also choose the option: Turbulence calculated by hydraulic diameter and choose the hydraulic diameter value. In my case, I don't know my initial value of k and epsilon so maybe I prefer to choose the default hydraulic diameter. My question is : how CS calculates the initial value of k and epsilon from the hydraulic diameter? If not, how CS use the hydraulic diameter to initialize the k - epsilon model?

Thanks in advance,
Regard,
Hong Duc

[Luciano Garelli]

Hello,

You can check these documentation about k-e initial values. Here is explained how it is computed and its implementation.

https://www.code-saturne.org/doxygen/sr ... _diam.html

https://www.code-saturne.org/doxygen/sr ... bc_8c.html

Regards,

Luciano

[lehongduc]

Hello,

Thanks a lot for the explanation.

Regard,
Hong Duc