[Belgio]

Help needed...

I am new to Flow3D, I'm trying to model the shock tube using the standard example model as a base. But it is impossible to change friction coefficient in turbulence settings (it is always -1.0). I've tried to change fluid viscousity and other parameters but that doesn't solve the problem. Friction is still -1.0.

Thanks in advance!

[MuxaB]

You need to activate the viscous model in Physics > Viscosity and Turbulence. Make sure also that there is a non-zero viscosity coefficient in the fluid properties.

Using a positive friction coefficient means a partial slip at walls. Is it what you want to do for the gas?

[Belgio]

Yes, I've tried what you said. Nothing helps. Miha! Pls. check your private inbox. Thx

[MuxaB]

Gleb,

If you have viscous flow activated and the viscosity is positive, then there is friction at walls. The friction coefficient stays at -1, as it should for all fluid. The -1 value effectively means infinite no-slip BC. A 0 value would mean free slip, and a positive value means partial slip, which is suitable for solid-like materials.

The fact that you do not see a noticeable effect on the shock is probably because the viscous boudnary layer is too thin to be resolved.

[jiushen]

Originally Posted by Belgio

Help needed...

I am new to Flow3D, I'm trying to model the shock tube using the standard example model as a base. But it is impossible to change friction coefficient in turbulence settings (it is always -1.0). I've tried to change fluid viscousity and other parameters but that doesn't solve the problem. Friction is still -1.0.

Thanks in advance!

dear Belgio,i have the same problem ,have you ever solved the problem?i want to set the frictional coefficient zero.thanks.

[Belgio]

No, I have not solved that.

[MuxaB]

Originally Posted by Belgio

No, I have not solved that.

Hi guys,

Do I understand correctly that you have not been able to simulate a shock wave in a test tube because you could not set a friction coefficeint?