Register to reply 
Fanning Friction Factor 
Share this thread: 
#1
Feb1114, 01:14 AM

PF Gold
P: 470

Hello,
I was wondering if when calculating the fanning friction factor, do english units need to be used? The equation for the head friction is h_f = 4f(L/D)V^2/2 where L is the length, D is the diameter of the pipe, and f is the fanning friction factor. This ends up having units of length squared/time squared, but I think it should be power/mass 


#2
Feb1114, 04:19 AM

Emeritus
Sci Advisor
HW Helper
Thanks
PF Gold
P: 6,325

I don't know about your dimensional analysis. The Fanning friction factor is nondimensional.
http://en.wikipedia.org/wiki/Fanning_friction_factor BTW, your formula for head loss due to friction is incorrect. It should be: h_f = 4f(L/D)V^2/(2g) 


#3
Feb1114, 10:19 AM

PF Gold
P: 470

Is the g included whether you use english units or not? I get confused when I need to divide by g or not these days since we keep going back and forth with english and SI units



#4
Feb1114, 12:24 PM

Emeritus
Sci Advisor
HW Helper
Thanks
PF Gold
P: 6,325

Fanning Friction Factor
Yes, the g is always there, even in SI or furlongs per fortnight units. Do a dimensional analysis and confirm.



#5
Feb1114, 11:11 PM

PF Gold
P: 470

You can see why I was confused, this is directly and repeatedly on the lecture slides



Register to reply 
Related Discussions  
Factor of friction strange behavior  General Physics  2  
Friction factor & velocity  General Physics  1  
Friction factor and Turbulent flow  Aerospace Engineering  6  
Friction factor on very very low reynolds number  Mechanical Engineering  6  
Fluid mechanics...friction factor formula  Mechanical Engineering  13 