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-   -   How to create an animated plot? (https://www.cfd-online.com/Forums/floefd-floworks-flotherm/93978-how-create-animated-plot.html)

george85 November 1, 2011 21:45

How to create an animated plot?
 
I saw a video on youtube, with air velocity made for a bikerman:

http://www.youtube.com/watch?v=6jlsF...eature=related

How can I do this?


This is what I tried to do, but obviously I am making mistakes somewhere.
I recorded the process in two files, due to youtube file size restriction:


part1 and the sequel part2


Thank you.

Boris_M November 6, 2011 15:57

Hi George,
The way you did it is correct but you have so few time steps and the scale is also very small it seems. For a good "flow" of the animation you need a more time steps to really see it (more than 4-5). Also I cannot tell how big they are and how fine the flow actually changes. Imagine a vortex street and you take results every time the vortex is one periode further. You won't see anything happening as you hit the exact moment when it is at the same position again. Just for a simple example.
I would assume it's all about scale here, time scale/steps and parameter color scale.
You could also cut off the mainly moving area of the parameter and keep the core so everything that is happening is in the blue region. For me it's just not possible to say what it is without a model.


Boris

george85 November 6, 2011 18:41

Thank you for the reply Boris. You are the only person in here willing to help.
Here is the model, if it will help you somehow:

http://www.gamefront.com/files/20968...+1a_vetarN.rar

Thank you.

Boris_M November 9, 2011 06:59

Ok, your model was not set up time dependent, therefore you won't be able to get a time dependent cut plot visualization.
Also as I said in the other post the mesh is way too coarse. You are trying to resolve something that is in 1m scale with a cell that it 5-10-times bigger.
You always have to consider you are trying to resolve something that happens in a certain dimension or time scale and you have to do that also in the mesh and time step.
I meshed your model with ~400.000 cells and this is not enough and you used just ~20.000 cells. Your buildings are ~10-15m high and you used 3-5 cells in the height. One cell is therfore ~3m in length. You see the roughness. It's like measuring your height to the centimeter accurate with a ruler which smallest scale is 10m.
So the animation you saw on youtube is done time dependent and the resolution of the mesh and the time step is able to capture the fluctuations in the flow accurate enough.

Boris

george85 November 20, 2011 14:39

Thank you for the reply Boris.

How can I increase the scale(or number) of my cells?

Boris_M November 20, 2011 15:56

If you go to "initial mesh" you can deactivate the "automatic settings" and manually increase the basic mesh by increasing the number of cells in x, y and z direction. Then you can adjust the level for partial cells, to increase the resolution at walls, and narrow channels, to increase the resolution in narrow gaps between the buildings. The narrow channel refinement can be controlled by defining the number of cells you would like in the channel and the maximum level that is allowed to create them, if not enough than it will not refine any more than the maximum.
The levels basically define the number of refinements based on the basic mesh. The basic mesh is therfore Level 0 and splitting the cells into 8 equal sized cells (in 2D seen like in a cut plot, in 4 cells). That way you can easily find out which level you should chose to refine correspondingly.

Boris

george85 December 14, 2011 06:19

Thank you for the help Boris, and sorry once again for my late reply.

I increased the Number of cells in X, Y, Z direction by 10 times.
And made a few small changes in the geometry.

But now, I am constantly having that irritating error:

"There is no fluid volume in the project. Please check geometry or boundary conditions."

Any suggestions, what could be the problem?
Here is the SolidWorks file:
http://www.gamefront.com/files/21107...ja_vetarN2.rar

Thank you.

Mochi January 3, 2012 16:00

I am defining a time step of 1s for a trasient process where I want to see 10s of data, but FloWorks is telling me, "Manual time step has been reduced" from 1s to 1.3e-08s. Why does FloWorks want such a tiny time step? Should I adjust my physical time to end at something on the order of this small time step and adjust my periodic savings accordingly in the calculation control options?

The model has 100psi inlet and 100LPM outlet and includes a narrow passage .005" tall. The mesh is tight around the passage such that the passage is at least 4 cells tall.

kimmj January 3, 2012 20:12

/Thank you for the help Boris, and sorry once again for my late reply.
/
/I increased the Number of cells in X, Y, Z direction by 10 times.
/And made a few small changes in the geometry.
/
/But now, I am constantly having that irritating error/
/
/"There is no fluid volume in the project. Please check geometry or boundary conditions."
/
/Any suggestions, what could be the problem?
/Here is the SolidWorks file:
/http://www.gamefront.com/files/21107...ja_vetarN2.rar
/Thank you. "

Error message
""There is no fluid volume in the project. Please check geometry or boundary conditions.""
means model have some problem.
Fix model..
How about contact your local support center ?

george85 January 4, 2012 03:39

Quote:

Error message
""There is no fluid volume in the project. Please check geometry or boundary conditions.""
means model have some problem.
Fix model..
How about contact your local support center ?
We did. They just said we need to reinstall the application.
Reinstalling the application did not help.

kimmj January 4, 2012 20:22

Quote:

Originally Posted by george85 (Post 337791)
We did. They just said we need to reinstall the application.
Reinstalling the application did not help.

Install is not the problem, I think.
If install is the problem, example files(ball valve or others) shows same error message.

I contact that error message, when I make some problem geometry model.- I mean, Surface model or mismatched edge model.

Can you give me model files?
If can't, try open each parts and do diagnostic(tool > import diagnostic)

Boris_M January 16, 2012 17:31

Hi Mochi,
it is usually the case that if FloEFD thinks there is too much happening in a short time it reduces the time step, somthimes it says it reduces it but doesn't and sometime it just gives a message that FloEFD suggests a shorter time step but leaves it to the one you selected.
So depending on what your simulation does, for example a super sonic nozzle like in a spray gun it needs a smaller time step if the calculation is starting from zero as the flow field is developing rapidly. you can try to reduce the time step a little more so it is not automatically reduced. Try 0.1 or 0.01 seconds or so. Of course you need more computation time but you can try to raise the time step after some time during the calculation.


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