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Haaland Equation

  1. Oct 21, 2010 #1
    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. jcsd
  3. Oct 21, 2010 #2

    vela

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    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?
     
  4. Oct 23, 2010 #3
    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.
     
  5. Oct 23, 2010 #4

    vela

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    The inverse of the log function is the exponential function ex.
     
  6. Oct 23, 2010 #5

    cjl

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