1d pipe flow vs 3D pipe flow

vishyaroon · May 20, 2009, 10:17

I'm a CFD person who does not have much experience in flows in pipes. My question is if the pipe length to diameter ratio is x (L/D = x), what is a safe value of x that I should have to consider the flow as one-dimensional? I was thinking about something in the order of 100. Is that a fair estimate?

I am looking into problem of cooling/heating in pipes and the L/D ~ 300.

SKK · May 20, 2009, 10:38

It all depends on the flow. For laminar flow the length is much higher, at about 120. For turbulent flow in a smooth pipe about 50.

May 20, 2009, 10:17	1d pipe flow vs 3D pipe flow	#1
vishyaroon Senior Member Aroon Join Date: Apr 2009 Location: Racine WI Posts: 148 Rep Power: 17	I'm a CFD person who does not have much experience in flows in pipes. My question is if the pipe length to diameter ratio is x (L/D = x), what is a safe value of x that I should have to consider the flow as one-dimensional? I was thinking about something in the order of 100. Is that a fair estimate? I am looking into problem of cooling/heating in pipes and the L/D ~ 300.

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May 20, 2009, 10:38		#2
SKK Member Join Date: Mar 2009 Posts: 55 Rep Power: 17	It all depends on the flow. For laminar flow the length is much higher, at about 120. For turbulent flow in a smooth pipe about 50.