Diffusion-related problem for Re=1

weymouth / lily-pad

Real-time two-dimensional fluid dynamics simulations in Processing. Initiated by Dr G D Weymouth:

https://github.com/weymouth/

MIT License

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Diffusion-related problem for Re=1 #1

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago

What steps will reproduce the problem?
1. Change Reynolds number to 1
2. QUICK scheme turned On
3. Allow for adaptive time step
4. Place two circular cylinders of equal size, D, at spacing 2D apart

What is the expected output? What do you see instead?
Expected: Suction Region in the wake of leading cylinder results in stabilizing 
effect on vortices of both cylinders
Seen: Diffusion of vorticity and disappearance of vorticity with erratic spread 
on upstream region

Please use labels and text to provide additional information.

Original issue reported on code.google.com by hendrikh...@gmail.com on 3 Oct 2012 at 5:20

GoogleCodeExporter commented 9 years ago

Hendrik, can you find an experimental reference for a single circular cylinder 
at Re=1 so we know what we should be seeing? You can attach images to these 
issues.

Original comment by DrWeymo...@gmail.com on 4 Oct 2012 at 3:43

GoogleCodeExporter commented 9 years ago

Hi Gabe, I have attached two figures. One for single circular cylinder at Re 
1.54 and the other one is for tandem circular cylinder with Center to Centre 
Distance of 2D and Re 0.01.

I would like to make small correction on the fourth steps to reproduce problem, 
it is the centre to centre distance that is 2D apart, not spacing. Thanks.

Original comment by hendrikh...@gmail.com on 5 Oct 2012 at 3:23

Attachments:

[Re 1.54.png](https://storage.googleapis.com/google-code-attachments/lily-pad/issue-1/comment-2/Re 1.54.png)
[Re 0.01.png](https://storage.googleapis.com/google-code-attachments/lily-pad/issue-1/comment-2/Re 0.01.png)

GoogleCodeExporter commented 9 years ago

[deleted comment]

GoogleCodeExporter commented 9 years ago

There is no recirculation in that top image, but one thing it does show is that 
the flow far from the cylinder is still highly disturbed. This indicates you 
will need a larger than usual computational domain for low Re flows. Can you 
put some LilyPad results up? Some streamline plots would be nice as well, to 
directly compare.

Original comment by DrWeymo...@gmail.com on 5 Oct 2012 at 4:08