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#1 |
New Member
Join Date: May 2012
Posts: 3
Rep Power: 14 ![]() |
I started a simple flow example:
rectangular block and make it partly nested half water (depth=0.3m) and half air a water flow with constant velocity comes from right boundary, u= 0.1 m/s the simulation will be easily done if 'one fluid' is chosen, whether 2-d or 3-d. However, if I choose two fluids(water and air), while all the other condition and parameters exactly the same with one fluid situation, the errors will occur. 'convective flux exceeded stability limit' will soon come along. After 2 or 3 of them, excessive convection failures make calculation terminated. And only 4e-09 second is calculated. I'm stuck....I need advice. Thank you! |
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#2 | |
Senior Member
michael barkhudarov
Join Date: Mar 2009
Location: Sante Fe, New Mexico, USA
Posts: 336
Rep Power: 18 ![]() |
Quote:
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#3 |
New Member
Join Date: May 2012
Posts: 3
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yes, there is an outlet boundary~
the mesh is as followed: block1 x:0~1.0, nxcelt=50, y:0~0.1, nycelt=5, z:0~0.5,nzcelt=25 ; block2 x:0.5~0.8,nxcelt=30, y:0.02~0.08, nycelt=6, z:0.1~0.4, nzcelt=30 ; Boundaries of block1 are: right: V , left: O , front and back: S , bottom:W , top:P ; for block2 they are all Symmetry |
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#4 |
Senior Member
michael barkhudarov
Join Date: Mar 2009
Location: Sante Fe, New Mexico, USA
Posts: 336
Rep Power: 18 ![]() |
hmm. is air modeled as compressible fluid?
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#5 |
New Member
Join Date: May 2012
Posts: 3
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The flow mode is chosen as incompressible, so both two fluids are calculated as incompressible, right?
I thought that inter-block boundary type coefficient(alphamb) might affect, so I changed it from default to 0.5 or 1.0, but still didn't work.... |
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#6 |
Senior Member
michael barkhudarov
Join Date: Mar 2009
Location: Sante Fe, New Mexico, USA
Posts: 336
Rep Power: 18 ![]() |
It is hard to figure out without seeing the problem. Have any ideas yourself?
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#7 |
New Member
Mahdiar Farhoudi
Join Date: Feb 2012
Location: Tehran, Iran
Posts: 17
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That is exactly my problem too!
did you get what to do? you can also check out: Help > CUSTOM TUTORIALS > Hydraulics Tutorial > Variation: Run as a Two-Fluid Problem |
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Tags |
nested block, two fluids |
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