Friction factor in rectangular channels

Curtin University · May 1, 2012, 07:30

Hi all,

I've come across several published literatures on science direct and engineering village along the topic of 'heat transfer in rib-turbulated internal cooling passages' where they refer to friction factor as: f=ΔpD/2ρLu^2.

From basic fluid mechanics, I would have thought that given: Δp=f(L/D)(ρu^2)/2, friction factor 'f' should be f=(2ΔpD)/(ρLu^2)?? i.e. the '2' should be a numerator rather than denominator.
Am I missing something here???

Thanks,

Curtin University · May 1, 2012, 08:05

Never mind! Found the answer to this... turns out there are two types of friction factors - fanning and darcy.

May 1, 2012, 07:30	Friction factor in rectangular channels	#1
Curtin University New Member Mo Ah. Join Date: Apr 2012 Posts: 9 Rep Power: 14	Hi all, I've come across several published literatures on science direct and engineering village along the topic of 'heat transfer in rib-turbulated internal cooling passages' where they refer to friction factor as: f=ΔpD/2ρLu^2. From basic fluid mechanics, I would have thought that given: Δp=f(L/D)(ρu^2)/2, friction factor 'f' should be f=(2ΔpD)/(ρLu^2)?? i.e. the '2' should be a numerator rather than denominator. Am I missing something here??? Thanks,

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May 1, 2012, 08:05		#2
Curtin University New Member Mo Ah. Join Date: Apr 2012 Posts: 9 Rep Power: 14	Never mind! Found the answer to this... turns out there are two types of friction factors - fanning and darcy.