loss coefficient

wilson · December 16, 2009, 14:40

I performed a laminar flow computation on a turbulent flow and found a loss coefficient of 3.54. Using the k-e model, the loss coefficient was 3.80. Why are these different? I think it is something to do with the dissipation of energy but I am looking for a better explanation.

Thanks

ghorrocks · December 16, 2009, 17:46

There are many reasons why if you magically make a flow laminar it could have lower loss coefficients. The main reason is probably due to the much reduced shear stress in the boundary layer leading to reduced drag, but there could be other reasons. For more information see a turbulence textbook.

December 16, 2009, 14:40	loss coefficient	#1
wilson New Member Mike Join Date: Dec 2009 Posts: 14 Rep Power: 17	I performed a laminar flow computation on a turbulent flow and found a loss coefficient of 3.54. Using the k-e model, the loss coefficient was 3.80. Why are these different? I think it is something to do with the dissipation of energy but I am looking for a better explanation. Thanks

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Outlet Vent Loss Coefficient	jpo	FLUENT	0	June 24, 2009 20:15
Automotive test case	vinz	OpenFOAM Running, Solving & CFD	98	October 27, 2008 09:43
bc's to find pres loss coefficient???	DON	Siemens	7	June 28, 2007 15:09
Loss coefficient at openings	Forrest	CFX	1	June 11, 2005 19:09
Need help for loss coefficient of elbow diffuser	Pete	Main CFD Forum	0	November 9, 2004 03:54

December 16, 2009, 17:46		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	There are many reasons why if you magically make a flow laminar it could have lower loss coefficients. The main reason is probably due to the much reduced shear stress in the boundary layer leading to reduced drag, but there could be other reasons. For more information see a turbulence textbook.