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how should i choose the inlet turbulent in boundary conditions?

Posted: Wed Nov 03, 2021 9:52 am
by Yvonne
Dear all!

Recently I simulated a water tank.
the tank is about 50 meters long, 4 meters wide, and the high (water depth) is 0.54 meters.
I chose the K-W SSTmodel as my turbulence model.
when I set the boundary conditions, I find that I can choose two types, one is the turbulent calculation by formula (k and w), another is a calculation by hydraulic diameter.

I think the tank is enough long and wide, so I can think this tank is a Wide shallow open channel,because the water depth is small in comparison to wide and long. so I would like to set the water depth as hydraulic diameter.

But I also have the value of the k and w.

so it means that I have two choices.

I don't know my understanding is correct (attached the screenshot)

Re: how should i choose the inlet turbulent in boundary conditions?

Posted: Thu Nov 04, 2021 3:34 pm
by daniele
Hi,

You can either impose directly the values of k and w at the inlet, if you know them, or estimate them based on correlations function of Dh , turbulence intensity, ...
If you don't know the k and w values, you are obliged to use a correlation.
Does this answer your question?
What does the inlet b.c. represent in your water tank?

Kind regards,
Daniele

Re: how should i choose the inlet turbulent in boundary conditions?

Posted: Sat Nov 06, 2021 2:57 pm
by Yvonne
hello!

Thank you for your answer.
In my understanding that I can choose the water depth or the k-w, only depending on which one I have. is it correct?

In my case, I want to simulate the one direction flow. so I think in my inlet, it has the flow come in.
I don't know if I understand your question?

Best wish,
Yvonne