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Homework Help: D'arcys Equation

  1. Aug 10, 2010 #1
    I have the question and the answer but just keep getting a different answer so here it goes.

    Darcy law h=(4fLv2(square root sign))/2gD

    h=head of water(m)
    f=Friction coefficient (0.007)
    L= equivalent length of pipework (m)
    v= velocity (m/s)
    g= acceleration due to gravity (9.81m/s2)
    D= pipe diameter

    Q. Over a distance of 25m, a 25mm diameter pipe loses 7m of pressure. Using the D'Arcy Equation, determine the velocity of water in the pipe and the flowrate in litres per second.

    Answer = v= 0.215m/s q= 1.086l/s

    Any help would be great thanks


    My attempt
    7=4x.007x25xv2/2x9.81x.025

    v2=5x2x9.81x.025/4x.007x25

    v2= 2.4525/.7
    v2=3.5035
    v=1.87m/s
     
  2. jcsd
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