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Low Re flow past cylinders in tandem

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Old   April 5, 2016, 02:48
Default Low Re flow past cylinders in tandem
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Sagar
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Hello all

I am trying to simulate a low Re (Re=100) flow past two cylinders in tandem and I am unable to get vortex shedding which is quite obvious and also reported in literature. When I tried ANSYS Mesh unstructured mesh I was able to get proper results, but when I tried to make a structured mesh with ICEM CFD, I am unable to reproduce proper results. I must say that I am a newbie in ICEM and I have a hunch that my meshing is not proper. So I am attaching the image of my mesh. Kidnly suggest how to go about it.

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Old   April 5, 2016, 09:16
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Quote:
Originally Posted by ksgr View Post
Hello all

I am trying to simulate a low Re (Re=100) flow past two cylinders in tandem and I am unable to get vortex shedding which is quite obvious and also reported in literature. When I tried ANSYS Mesh unstructured mesh I was able to get proper results, but when I tried to make a structured mesh with ICEM CFD, I am unable to reproduce proper results. I must say that I am a newbie in ICEM and I have a hunch that my meshing is not proper. So I am attaching the image of my mesh. Kidnly suggest how to go about it.

Regards
with this mesh you cannot get any results, let alone vortex shedding

Create ogrid around both circles and run the solution.
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Old   April 5, 2016, 09:29
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with this mesh you cannot get any results, let alone vortex shedding

Create ogrid around both circles and run the solution.
Thanks Far.

I knew mesh was the culprit. However, I am not able to figure out how to create O grid meshing around 2 circles. I was able to do it successfully for a single circle. With 2 circles, when I try to split block around small circle, it intercepts with the larger circle. Kindly suggest any tutorials where I can learn about blocking for these kind of geometries.

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Old   April 5, 2016, 13:52
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which cylinder is upstream? smaller or larger?
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Old   April 5, 2016, 14:18
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Smaller cylinder is upstream and the gap between them is 1.2 times the diameter of the bigger cylinder.
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Old   April 5, 2016, 17:00
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In the mean time I tried creating two separate O grid blocks around 2 circles and it looks like this. I'm pretty sure it is not correct. Could you kindly suggest what changes I could make?
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Old   April 10, 2016, 17:59
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which cylinder is upstream? smaller or larger?
Could you please suggest how to make a blocking in this case? I'm not able to figure out perfect blocking strategy so far. Any help would be much appreciated.
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