bigger or smaller enclosure box

syafiq · October 12, 2011, 05:56

hi,
im doing analysis on a blunt body.
which one is better, using bigger or smaller enclosure box? and why?

any opinion?

cheers

ghorrocks · October 12, 2011, 07:43

If you want to model the body moving through the open atmosphere then a big enclosure box (because it reduces proximity effects). If you want to model the body in an enclosed space like a wind tunnel then model the wind tunnel as the enclosure.

syafiq · October 13, 2011, 05:46

do size of enclosure box will affected the results?
why is that?

ghorrocks · October 13, 2011, 06:08

Yes it does. It is one of the basic checks you need to do for far-field simulations. When your boundaries are too close it will cause an error in the simulation by artificially constraining the flow.

October 12, 2011, 05:56	bigger or smaller enclosure box	#1
syafiq New Member Muhamad Sulaiman Join Date: Aug 2011 Posts: 8 Rep Power: 15	hi, im doing analysis on a blunt body. which one is better, using bigger or smaller enclosure box? and why? any opinion? cheers

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October 12, 2011, 07:43		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	If you want to model the body moving through the open atmosphere then a big enclosure box (because it reduces proximity effects). If you want to model the body in an enclosed space like a wind tunnel then model the wind tunnel as the enclosure.

October 13, 2011, 05:46		#3
syafiq New Member Muhamad Sulaiman Join Date: Aug 2011 Posts: 8 Rep Power: 15	do size of enclosure box will affected the results? why is that?

October 13, 2011, 06:08		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	Yes it does. It is one of the basic checks you need to do for far-field simulations. When your boundaries are too close it will cause an error in the simulation by artificially constraining the flow.