length where solution will be influenced by the outlet condition

nnvoro · July 2, 2013, 12:38

Hello!

I'm modelling laminar incompressible newtonian flow in curved pipe. I need to calculate pressure drop. For that I need to take two pressure measurements: one - at the beginning of the pipe, another - at the end. I have velocity inlet and pressure outlet.

I can't take pressure measurement too close to the outlet and inlet, because my outlet/inlet boundary condition will influence solution. I can calculate entrance length to do the first pressure measurement but I didn't find anything for the outlet condition. I need to know the length where solution will be influenced by the outlet condition. Does anybody know is there analogue to entrance length for the outlet boundary condition?

I would really appreciate any help

nnvoro

francisco.angel · June 14, 2019, 00:28

Just try various outlet lengths and check when the result become independent of said length.

July 2, 2013, 12:38	length where solution will be influenced by the outlet condition	#1
nnvoro New Member Join Date: Apr 2013 Posts: 17 Rep Power: 13	Hello! I'm modelling laminar incompressible newtonian flow in curved pipe. I need to calculate pressure drop. For that I need to take two pressure measurements: one - at the beginning of the pipe, another - at the end. I have velocity inlet and pressure outlet. I can't take pressure measurement too close to the outlet and inlet, because my outlet/inlet boundary condition will influence solution. I can calculate entrance length to do the first pressure measurement but I didn't find anything for the outlet condition. I need to know the length where solution will be influenced by the outlet condition. Does anybody know is there analogue to entrance length for the outlet boundary condition? I would really appreciate any help nnvoro

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
outlet boundary condition	Nina Schiepel	CFX	2	July 12, 2008 15:27
Outlet boundary condition for pd in InterFoam	gopala	OpenFOAM Running, Solving & CFD	0	March 19, 2008 09:26
Outlet boundary condition	Asghari	Main CFD Forum	0	May 5, 2006 16:51
Outlet velocity boundary condition	Jay	FLUENT	4	December 15, 2002 08:27
How can define our Outlet Condition?	POR	FLUENT	0	October 11, 2002 06:24

June 14, 2019, 00:28		#2
francisco.angel New Member Francisco Angel Join Date: Dec 2012 Posts: 26 Rep Power: 13	Just try various outlet lengths and check when the result become independent of said length.