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August 8, 2013, 08:22 |
Question about Relative Velocity
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#1 |
New Member
Ding Chao
Join Date: Aug 2013
Posts: 5
Rep Power: 12 |
Hi,everyone
I am modeling a bubble flow useing CFX,and I need use relative velocity in CCL. I find that the slip velocity have no unit in the CFX reference_Guide,and I don't know this is why.Could anyone explain to me the question? Could I use this expression to calculate the relative velocity? Vr=sqrt((air.Velocity u-water.Velocity u)^2+(air.Velocity v-water.Velocity v)^2+(air.Velocity w-water.Velocity w)^2) If anyone know the answer,please help me! |
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August 8, 2013, 18:58 |
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#2 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
Seems strange. I would have thought slip velocity would be in m/s. Also make sure you are using the correct variable. There is "Slip Velocity" for ASM models, "particle Slip velocity" for particles, "Slip Velocity Magnitude".
There should be no need to calculate this, it should already be a variable in the solver. You just have to find the right variable name. |
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August 8, 2013, 21:10 |
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#3 | |
New Member
Ding Chao
Join Date: Aug 2013
Posts: 5
Rep Power: 12 |
Quote:
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August 8, 2013, 22:11 |
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#4 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
I don't understand it either. It might be a documentation mistake. Also we might be misunderstanding the variable. I am not sure which is the case.
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August 8, 2013, 23:02 |
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#5 |
New Member
Ding Chao
Join Date: Aug 2013
Posts: 5
Rep Power: 12 |
Thank you all the same!what do you think that if I use" Vr=sqrt((air.Velocity u-water.Velocity u)^2+(air.Velocity v-water.Velocity v)^2+(air.Velocity w-water.Velocity w)^2)"to calculate the relative velocity between gas and liquid?Is it accurate?
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August 8, 2013, 23:26 |
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#6 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
I suspect the value you get from your equation should be the same as Slip Velocity Magnitude, providing you are doing an ASM model. Is it the same?
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