Boundary condition for C-grid airfoil with gridgen

quarkz · December 28, 2010, 14:40

Hi,

I have generated a c-grid for an airfoil using gridgen. However, there is an imaginary horizontal line connecting the top and bottom grids. What boundary condition do I use for that line? Or how can I eliminate the line?

Thanks!

rmatus · December 28, 2010, 15:00

By default, Gridgen will set that line to a Type-1 BC. A Type-1 BC is a point-to-point matched interface. When you export the grid to your CFD code Type-1 BCs just show up as interior grid, i.e. it is treated as any other interior cell and not as a boundary.

You can check this in the ASW, Set BCs menu. If it was not set to Type-1 automatically, it may mean you have duplicate connectors there. If it is set to Type-1, it should be ready to export to your CFD code.

quarkz · December 29, 2010, 07:38

Hi thanks rmatus, never expect it to be so simple. ;-)

December 28, 2010, 14:40	Boundary condition for C-grid airfoil with gridgen	#1
quarkz Senior Member TWB Join Date: Mar 2009 Posts: 400 Rep Power: 19	Hi, I have generated a c-grid for an airfoil using gridgen. However, there is an imaginary horizontal line connecting the top and bottom grids. What boundary condition do I use for that line? Or how can I eliminate the line? Thanks!

December 28, 2010, 15:00	Should not have to set a BC there	#2
rmatus Senior Member Rick Matus Join Date: Mar 2009 Location: Fort Worth, Texas, USA Posts: 116 Rep Power: 17	By default, Gridgen will set that line to a Type-1 BC. A Type-1 BC is a point-to-point matched interface. When you export the grid to your CFD code Type-1 BCs just show up as interior grid, i.e. it is treated as any other interior cell and not as a boundary. You can check this in the ASW, Set BCs menu. If it was not set to Type-1 automatically, it may mean you have duplicate connectors there. If it is set to Type-1, it should be ready to export to your CFD code.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
airfoil boundary condition	Bounecer	Main CFD Forum	6	April 12, 2012 12:06
Mixed/Robin boundary condition	aaev	OpenFOAM Bugs	2	December 15, 2011 14:03
setting boundary condition for curvlinear grid	taw	Main CFD Forum	2	February 5, 2010 17:23
SymmetryPlane Boundary Condition	raytracer	OpenFOAM Running, Solving & CFD	0	July 11, 2008 17:04
Multiblock grid, interface Boundary condition	Nandu	CFX	2	August 6, 2002 05:07

December 29, 2010, 07:38		#3
quarkz Senior Member TWB Join Date: Mar 2009 Posts: 400 Rep Power: 19	Hi thanks rmatus, never expect it to be so simple. ;-)