Opening boundary as far field

stefan23 · November 30, 2011, 12:45

Hello,

is it possible to use the Opening boundary condition in CFX (Entrainment, Static Pressure Option, Relative Pressure = 0) as a far field?

I have a half sphere around my model, similar to the helicopter tutorial in ICEM CFD. The dimension of the sphere is about a hundred times as large as the model itself. I don't want to use a rectangular domain because the flow direction shall be changed later on.

Thanks for your help!

Stefan

ghorrocks · November 30, 2011, 17:54

Any boundary condition can behave as a far field if it is far enough away from the action. Do a sensitivity analysis to check it is far enough away. You will find different boundary condition approaches will allow the boundary to be different distances away before it acts like a far-field to your accuracy tolerance.

November 30, 2011, 12:45	Opening boundary as far field	#1
stefan23 New Member Join Date: Nov 2011 Posts: 4 Rep Power: 15	Hello, is it possible to use the Opening boundary condition in CFX (Entrainment, Static Pressure Option, Relative Pressure = 0) as a far field? I have a half sphere around my model, similar to the helicopter tutorial in ICEM CFD. The dimension of the sphere is about a hundred times as large as the model itself. I don't want to use a rectangular domain because the flow direction shall be changed later on. Thanks for your help! Stefan

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November 30, 2011, 17:54		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	Any boundary condition can behave as a far field if it is far enough away from the action. Do a sensitivity analysis to check it is far enough away. You will find different boundary condition approaches will allow the boundary to be different distances away before it acts like a far-field to your accuracy tolerance.