entrance length

hamid1 · February 10, 2012, 04:28

hi

i have a question, in case of considering a pipe with pressure b.c. do we need to consider the ""entrance length" ?
what about the other type of b.c?
thank u

delaneyluke · February 10, 2012, 05:47

If by entrance length you mean an extended domain before the pipe inlet, then yes you need to for all types of BC's , unless you have a fully developed profile that you'll use as the inlet BC.

Regards
Luke

hamid1 · February 10, 2012, 06:56

thanks Luke for the reply
im a bit confused, i have a T shape pipe and I know the pressure in openings of the pipe (the bc), shall i consider the pipe larger than it is to have a fully developed regime, or pressure bc will by default consider all the "normal gradient" zero, so by this assumption of fluent, the flow is fully developed,
for example in case of using velocity inlet bc, one have to consider the le=0.06 Re as length until the flow become fully developed in laminar regime....

bf3g10 · February 10, 2013, 06:27

I, too, am curious about this consideration of the entrance length as I have a similar T pipe configuration.

February 10, 2012, 04:28	entrance length	#1
hamid1 Senior Member hamid Join Date: Nov 2010 Posts: 185 Rep Power: 15	hi i have a question, in case of considering a pipe with pressure b.c. do we need to consider the ""entrance length" ? what about the other type of b.c? thank u

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February 10, 2012, 05:47		#2
delaneyluke Senior Member Join Date: Mar 2009 Location: Indiana, US Posts: 186 Rep Power: 17	If by entrance length you mean an extended domain before the pipe inlet, then yes you need to for all types of BC's , unless you have a fully developed profile that you'll use as the inlet BC. Regards Luke

February 10, 2012, 06:56		#3
hamid1 Senior Member hamid Join Date: Nov 2010 Posts: 185 Rep Power: 15	thanks Luke for the reply im a bit confused, i have a T shape pipe and I know the pressure in openings of the pipe (the bc), shall i consider the pipe larger than it is to have a fully developed regime, or pressure bc will by default consider all the "normal gradient" zero, so by this assumption of fluent, the flow is fully developed, for example in case of using velocity inlet bc, one have to consider the le=0.06 Re as length until the flow become fully developed in laminar regime....

February 10, 2013, 06:27		#4
bf3g10 New Member Ben Join Date: Nov 2012 Location: United Kingdom Posts: 11 Rep Power: 13	I, too, am curious about this consideration of the entrance length as I have a similar T pipe configuration.