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-   -   Structured mesh for airfoil (http://www.cfd-online.com/Forums/pointwise/70312-structured-mesh-airfoil.html)

 doubtsincfd November 20, 2009 04:14

Structured mesh for airfoil

Hi!
I am trying to generate a structured mesh around an airfoil using Gridgen software. The grid should provide for implementation of periodic boundary condition (boundaries parallel to the flow direction). Also there is clustering near the leading edge of the airfoil. Is it possible to generate an O grid with these constraints? What type of grid will suffice these conditions? I tried using cartesian grid but because of the clustering requirement the aspect ratio of the cells near the top and bottom boundary becomes large (as the grid is clustered near the leading edge in x direction but the spacing increases in y direction as we move away from the airfoil)

 jchawner November 21, 2009 10:51

Hello doubtsincfd.

In general, meshing an airfoil with H, O, C, or other topology is not a problem for Gridgen or any other decent software for that matter.

What I don't understand is the requirement for periodicity. Where exactly in the 2D O-grid will you be applying periodicity? There will be three boundaries: the outer farfield boundary, the airfoil surface, and the wake coming off the trailing edge and going to the outer boundary. The wake is an interblock connection or pass-thru boundary and won't be periodic. What am I misunderstanding?

 doubtsincfd November 21, 2009 15:32

The airfoils are stacked one over other. In such case how can I apply periodic boundary condition on the far field boundary since the far field boundary will have an O or C shape?

 jchawner November 21, 2009 17:16

Doubts:

It would be better if you could either attach a picture or email me your geometry in a format that Gridgen or Pointwise can read. Thanks.

 doubtsincfd November 23, 2009 00:02

Or maybe I can simplify my problem....
What shape of domain(outer/far field boundary) should I use if I want to generate a structured grid for flow over stacked airfoils and if I want to simulate by using periodic boundary condition?
Thanks for the help!

 jchawner November 23, 2009 09:31

Doubts:

Sounds like you might be doing a 2D simulation of a blade row in a turbomachine and need periodicity between the blades. Of course, the simplest topology would be to use a straight line for the periodic boundary. But that depends, of course, on the geometry of the blades and the other requirements of your grid like how fine it will be for accuracy near the blade surface and whether the surface topology will extend all the way to the outer boundary.

Don't hesitate to contact our Tech Support at 888-4PTWISE or support@pointwise.com - they'll be happy to help you work through all the options.

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