# Haaland Equation

1. Oct 21, 2010

### dearmrfantasy

1. The problem statement, all variables and given/known data

Using the Haaland equation shown below, determine the Reynold number Re

Friction factor λ = 0.032mm = 0.000032m
Absolute roughness Ks = 1.5 x 10-6m
Internal bore diameter d= 0.04m

1/√ λ = -1.8log[(6.9/Re) + [(ks/d)/3.7]1.11]

I have tried to solve the above equation but haven't got a clue as I have not been taught to this level. Consequently it's a bit unfair. Someone tried to help me but confused me even more. I do know the answer but need to show how I got the answer.

Any help would be appreciated.

2. Oct 21, 2010

### vela

Staff Emeritus
It seems a bit surprising you'd be working with an equation like this if you haven't mastered basic algebra yet. Where are you getting stuck?

3. Oct 23, 2010

### dearmrfantasy

Basic algebra yes but other people are speaking about anti logs? The left hand side of the equation is easy but I am struggling with the first part of the right hand side.

1/√0.032=-1.8log[(6.9/Re)+[( 1.5 x 10-6/0.04)/3.7]1.11]

Any help would be appreciated.

4. Oct 23, 2010

### vela

Staff Emeritus
The inverse of the log function is the exponential function ex.

5. Oct 23, 2010

### cjl

Well, more generally, the inverse of the log base n function is the exponential nx. So, logn(nx) = x.