CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   Fluent velocity magnitude contours (http://www.cfd-online.com/Forums/fluent/110754-fluent-velocity-magnitude-contours.html)

Al-Hashimi December 19, 2012 15:26

Fluent velocity magnitude contours
 
2 Attachment(s)
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

Attachment 17743

Attachment 17744

flotus1 December 21, 2012 09:22

Did you really run only one time step as the first picture suggests?

Al-Hashimi December 21, 2012 09:37

Yes, but what is this mean freind?

flotus1 December 21, 2012 10:28

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.

Al-Hashimi December 21, 2012 10:38

but is this the reason that i have a blue counors? Thank you very much for your reply.

flotus1 December 21, 2012 10:57

Yes it is.

Al-Hashimi December 21, 2012 11:52

1 Attachment(s)
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

Attachment 17773

flotus1 December 21, 2012 12:38

OK, there is another problem...
If you plot a velocity contour on a no-slip wall, the values must be zero.

Al-Hashimi December 21, 2012 17:45

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 ^_^

Al-Hashimi December 23, 2012 03:41

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

Al-Hashimi December 25, 2012 05:23

Any Answes ...

-mAx- January 3, 2013 02:19

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.


All times are GMT -4. The time now is 17:33.