[Tobi]

Hi all,

I have just a very simple question to you.
The last week I made a complex simulation of a static mixing element in a pipe.

I simulated with kOmegaSST and simpleFoam.
The first calculation was with the following conditions:

massflow: 30 kg/h
temperature: 200°C

Re: 3840

The solver was working but the lines of the residuals are very bad (see attachment - lowMassFlow.png)

After that I calculated the same with new conditions:

massflow: 1000 kg/h
temperature: 200°C

Re: 128007

My question is now. Could it be possible that the kOmegaSST model is inaccurat in a low turbulence flow? What should I use there instead? Compared with the residuals of the highMassFlow.png I am wondering why its more stable that with low mass flow.

And is the turbulence model causing the instability of the calculation?

Thanks in advance for any hint.

Tobi

[jherb]

Hi Tobi,

did you find a reason for the bad residuals of the low mass flow case?

Joachim

[Tobi]

Hey Joachim,

sorry for the late answer but there I was not investigate more time because it was only an own project. I think the BC were bad