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Old   December 19, 2012, 15:26
Default Fluent velocity magnitude contours
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Osamah Ali Al-Hashimi
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Hello,

when viewing the results of my simulation, i can't seem to be able to view the velocity magnitude contours (they appear completely blue i.e. 0 m/s).
It is right that I have no slip/velocity at wall but the default interior fluid is blue also.
Please why this is happening? Many thanks for your time.
My simulation is: Mixture of water sand,
Material: Water-liquid (density 988, viscosity: 0.001) & sand (density: 1300, viscosity: 0.0011) (I here entered the spcifcations of the slussy not the soil becouse the soil has no viscosity)
Boundary coinditions: Inlet velocity: 7 m/s. wall – no slip.
Refernce values: defult.
Soultion intiation: defult.

Osamah Ali

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Old   December 21, 2012, 09:22
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Did you really run only one time step as the first picture suggests?
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Old   December 21, 2012, 09:37
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Yes, but what is this mean freind?
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Old   December 21, 2012, 10:28
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It means that your solution has only advanced one second (your time step size) in time starting from your initial conditions.

If you really want to run a transient analysis, you will have to run more than one time step.
Otherwise a steady state-analysis would be better.
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Old   December 21, 2012, 10:38
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but is this the reason that i have a blue counors? Thank you very much for your reply.
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Old   December 21, 2012, 10:57
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Yes it is.
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Old   December 21, 2012, 11:52
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Many Many thanks for the assistant,
I made it as follows;
time steps: 0.6
Number; 30
i think the running time is 0.6x30 = 18 s
Max Iteration: 6.

but no change ...

Thank you again for your kindness

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Old   December 21, 2012, 12:38
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OK, there is another problem...
If you plot a velocity contour on a no-slip wall, the values must be zero.
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Old   December 21, 2012, 17:45
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Many Many Thanks for everything Mr. Alex ... i know that at the wall the vecolcity is 0, the pictures i sent you is for the enternal fluid.
i will try somethings eals which may be helpful and will inform you later.
Again, many many thanks for everything ... i wish you mery christmas ^_^
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Old   December 23, 2012, 03:41
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Dear Sirs,
I did everything to get results but I couldn’t … I’m really got tired. Can you please take a look on my model and see if there is a problem. I did it as follows:
The model is sand separator from water by centrifugal force, I want to separate sand with diameter 20 micron and higher.
Mesh Check
Domain Extents:
x-coordinate: min (m) = -3.129762e+000, max (m) = -3.044762e+000
y-coordinate: min (m) = 9.568687e-001, max (m) = 1.069369e+000
z-coordinate: min (m) = -2.000000e-002, max (m) = 5.317000e-001

Model:
Mixture with slip velocity, 2 phases.
Viscous: k-e with standard, standard wall.

Materials:
water h20 from fluent data base and sand which I made it as follows:
First time, i chooses AIR. i deleted the name of AIR, and rename this name by sand. And then, when I hit the Change/Create button, it display the message "... overwrite Air?” And then i click NO. Clicked on sand and change all values such as Density, Viscosity ... then clicked Change/Create button. That is all.</SPAN>

Models:
Primary = water liquid.
Secondary = sand with diameter 0.03mm
Boundary conditions:
Inlet velocity of: 7.37 m/sec
Initiation of solution,
Calculation with run time:
I tried 0.006 for 100 iteration
And 0.6 x 30 for 10 iteration but no result.
The default interior is blue, I.e. 0 velocity at all.


here is my model:

https://docs.google.com/open?id=0B1F...zdGNmJhWXRDRWs
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Old   December 25, 2012, 05:23
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Any Answes ...
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Old   January 3, 2013, 02:19
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try to run your model first with simple physics.
Incompressible, one phase and steady.
Once you get something reasonable, you can switch to multiphase, and then unsteady.
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