Maths help / Excel

crisbduck · 28 Apr 2011 at 18:21

Hey I've spent ages working out how to get this into excel and to arrange it to find λ

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Basically trying to find the friction factor of a pipe (y)

I got 1/SQRT λ = -5.2
so λ = ~25
Cheers for any help

crisbduck · 28 Apr 2011 at 18:36

sorry thought id added the caption to the pick!
Re - 21895
d - 13.6
k - 0.0015

crisbduck · 28 Apr 2011 at 18:39

Would like to know if i'm right and how to put it into an excel document, I keep getting errors with the log and power functions..

edit - pretty sure its base 10, it doesn't actually say in the lecture notes but id guess they would put ln for e?

crisbduck · 28 Apr 2011 at 18:54

Mason- said:
=(1/(-1.8*log((6.9/21895)+((0.0015/13.6)/3.71))^1.11))^2

0.020896244...

Probably wrong but oh well.

Hey that excellent, using the table a few scrolls down this page (http://knol.google.com/k/how-to-calculate-pressure-drop-and-friction-losses-in-a-pipe#) the table says about 0.02
I can't get it to work in excel though, i get a number error, Thanks though that's a great step forward

=/ I want to kill myself 13.6 should be 0.016 as its meant to be in metres...