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#1 |
New Member
Belgio
Join Date: Oct 2009
Posts: 9
Rep Power: 15 ![]() |
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! |
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#2 |
Senior Member
michael barkhudarov
Join Date: Mar 2009
Location: Sante Fe, New Mexico, USA
Posts: 336
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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? |
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#3 |
New Member
Belgio
Join Date: Oct 2009
Posts: 9
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Yes, I've tried what you said. Nothing helps. Miha! Pls. check your private inbox. Thx
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#4 |
Senior Member
michael barkhudarov
Join Date: Mar 2009
Location: Sante Fe, New Mexico, USA
Posts: 336
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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. |
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#5 | |
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HLD
Join Date: Jan 2011
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Quote:
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#6 |
New Member
Belgio
Join Date: Oct 2009
Posts: 9
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No, I have not solved that.
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#7 |
Senior Member
michael barkhudarov
Join Date: Mar 2009
Location: Sante Fe, New Mexico, USA
Posts: 336
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coefficient, friction |
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