Boundary condition for C-grid airfoil with gridgen

quarkz · December 28, 2010, 15:40

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, 16:00

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, 08:38

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

December 28, 2010, 15:40	Boundary condition for C-grid airfoil with gridgen	#1
quarkz Senior Member TWB Join Date: Mar 2009 Posts: 414 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, 16:00	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.

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December 29, 2010, 08:38		#3
quarkz Senior Member TWB Join Date: Mar 2009 Posts: 414 Rep Power: 19	Hi thanks rmatus, never expect it to be so simple. ;-)