# Axisymmetric Flow around a hollow cylinder with an extended flair

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 September 27, 2011, 23:01 Axisymmetric Flow around a hollow cylinder with an extended flair #1 New Member   Nishit Joseph Join Date: Nov 2010 Posts: 29 Rep Power: 15 Greetings OpenFOAM users! I am trying to simulate the flow past a hollow cylinder with an extended flair at a Ma=11.5. Until now i just modeled it as a 2D case, which physically ignores the curvature. I no longer want to assume the curvature is ignored. An axisymmetric solution, I am assuming will help me overcome this problem. My question is how do I go about defining the mesh. I have seen some of the post in this forum and all seem to have the axis as part of the region of interest. It is not the case for me, I am interested of the flow outside the hollow cylinder and have no mesh points in the inside of the cylinder. Is there a way to achieve this in OF? Thanks you all in advance. Cheers! NJ

 September 28, 2011, 06:54 #2 Member   Daniel Join Date: Apr 2010 Location: Manchester Posts: 30 Rep Power: 16 Does your geometry have a leading edge which will cause shocks?

September 28, 2011, 22:26
#3
New Member

Nishit Joseph
Join Date: Nov 2010
Posts: 29
Rep Power: 15
Quote:
Yes there is a leading edge. Please check out the image of the leading edge where I modelled it for the 2D case where curvature is ignored.

The actual case is based on the following paper

http://citeseerx.ist.psu.edu/viewdoc...10.1.1.26.1088

Cheers!

Nishit
Attached Images
 Ma11.png (18.7 KB, 67 views)

 September 30, 2011, 12:58 #4 Member   Daniel Join Date: Apr 2010 Location: Manchester Posts: 30 Rep Power: 16 Gschaider's excellent tool for making an axisymmetric mesh (a one cell thick wedge) can be used at zero angle of attack: http://openfoamwiki.net/index.php/Contrib_MakeAxialMesh Since it's hollow you need to create a patch which is parallel to the wall but offset by the radius of the cylinder. You might need to play around with different boundary conditions for the part of the inlet which will effectively become a flat wall. If you want to look at non-zero angles of attack then I wrote a guide on how I simulated 3D flow around an axisymmetric body at high angle of attack. The guide can be found on the OF wiki: http://openfoamwiki.net/index.php/Me...etric_Problems It might not be of direct relevance because I used a hemispherical rather than a cylindrical domain.

 October 3, 2011, 18:42 #5 New Member   Nishit Joseph Join Date: Nov 2010 Posts: 29 Rep Power: 15 Daniel Thank you for your suggestion. I will try it out, hopefully I get a run done today. Cheers! Nishit

 January 28, 2013, 12:11 #6 New Member   anonymous Join Date: Jan 2012 Location: Canada Posts: 24 Rep Power: 14 Hi guys I have a similar problem, simulating the flow around a hollow cylinder and I want to do the 2D simulation, considering the curvatures and I do not have a zero angle of attack. Can anybody help me with the mesh with a little bit more detail. Thanks