Sudden expansion

kmgraju · July 28, 2011, 03:28

Dear friends
I have a question on fluid mechanics.

a 6cm dia pipe expands gradually to 9 cm dia pipe. walls of expansion section are angled 10 degree from the horizontal. if the flow exit from smaller to bigger dia pipe there is a flow separation in the downstream flow for certain length and then the flow becomes fully developed .
How to calculate exactly the distance from the start of expansion to the fully developed flow starts in the downstream flow?

Thanks

Regards
Govind

ghorrocks · July 28, 2011, 03:33

Put a line across the downstream flow and take a velocity cross section. Then push the line downstream until the velocity is fully developed to within a tolerance you specify.

kmgraju · July 28, 2011, 12:27

Quote:

Originally Posted by ghorrocks

Put a line across the downstream flow and take a velocity cross section. Then push the line downstream until the velocity is fully developed to within a tolerance you specify.

Thanks for your information. Is there any mathematical method to calculate where the flow starts to develop fully?

Thanks

Regards

Govind

ghorrocks · July 28, 2011, 19:35

What do you mean by mathematical? My description is mathematical.

July 28, 2011, 03:28	Sudden expansion	#1
kmgraju Senior Member Govindaraju Join Date: Apr 2010 Posts: 209 Rep Power: 18	Dear friends I have a question on fluid mechanics. a 6cm dia pipe expands gradually to 9 cm dia pipe. walls of expansion section are angled 10 degree from the horizontal. if the flow exit from smaller to bigger dia pipe there is a flow separation in the downstream flow for certain length and then the flow becomes fully developed . How to calculate exactly the distance from the start of expansion to the fully developed flow starts in the downstream flow? Thanks Regards Govind

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July 28, 2011, 03:33		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 18,017 Rep Power: 146	Put a line across the downstream flow and take a velocity cross section. Then push the line downstream until the velocity is fully developed to within a tolerance you specify.

July 28, 2011, 19:35		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 18,017 Rep Power: 146	What do you mean by mathematical? My description is mathematical.