Ribbon

Hi,

I am currently running some simulation with the last version of Caedium (which is looking great well done), and I am in trouble to put Particles Tracks into my volume. I follow the description done into:
Incompressible Flow Through a Pipe into a Box

But it didn't looks good
https://dl.dropboxusercontent.com/u/71142308/RibbonProblems050913.png

I should have done a mistake, if you could help me?

Thanks in advance.

Pierre.

Create and transform geometry at simulation time = 0

It appears that you created the seed face and transformed it while the simulation time was at 100s. If you do this then it will animate the face, i.e., it will move with each iteration. If you want to create geometry and transform it after your simulation has run then:

  1. Save a copy of simulation so you don't corrupt the complete solution
  2. Toggle the Lock button
  3. Click the Start button to return to time = 0
  4. Create and transform your seed face
  5. Create your particles as normal
  6. Toggle the Unlock button to return to the end of the simulation

In its current state you should delete the animation transform. Select the Time:100 property (pink highlight means it can be deleted) in the screenshot, right-click, and select Delete. Then perform the transform again, given your simulation time = 0.

You don't have to create seed geometry if existing geometry that is part of your flow volume is already in a good position. Instead just use the existing geometry as the seed.

Also you can release particles from an outlet and given that the default integration is performed both upstream and downstream the streamlines that arrive at that outlet from upstream will be created.

Hi, Many thanks for this

Hi,
Many thanks for this answer. I may have done something bad in termes of complexity! First of all, I am happy to run simulation with ribbon at the begining so before trying the way you propose to me I went back to a very simple case: a hole into a pipe
https://dl.dropboxusercontent.com/u/71142308/ribbon.png
I follow (probably not correctly) the same method as in the tuto (note that the tuto it is working well) but the ribbons never goes arround the hole! I also made several tests with a new face, without, changing the accuracy, etc...
Many thanks for your help.
Pierre.

Try decreasing the Particles Increment

Some ideas:

Check you are using the face as your particles source (looks like you might have used its edges) and the flow volume as your particles target (looks like you might have used the horizontal cylinder face), as in the tutorial.

Is your flow volume mesh sufficiently fine enough to pick up the flow details around the vertical cylinder. For more on mesh control see "Accuracy Tool".

It appears that your Particles->Increment is too large for the velocity, try decreasing it by a factor of 10, as described in "Particles or Streamlines".

Also you might want to reduce the ribbon width using Particles->Type:Ribbon->Width

Ribbon

Ok that make it works well (in fact I divide increment and width by 100 ).

Many thanks.
Pierre.