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Water Flow Rate From A Tap Attached 2 A Tank

  1. Aug 25, 2008 #1
    Hi guys. Can u pls hlp me out.

    Let's say I have a 400 liter cylindrical tank with a tap at the botom.

    how do I calculate the rate at which the water flows from the tap and how far the water mite go?

    thanx in advance
  2. jcsd
  3. Aug 25, 2008 #2


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    The flow rate at the outlet can be found using Bernoulli's equation along with the continuity equation.

    [tex]v_2 = \sqrt{{\frac{2}{1- \left( \frac{A_2}{A_1}\right)^2}} \cdot \left(\frac{P_1 - P_2}{\rho} + g \cdot h \right) [/tex]


    EDIT: I forgot to mention that you need to multiply v2 by the cross-sectional area to get the flow rate (v2 is just the velocity).
    Last edited: Aug 25, 2008
  4. Aug 29, 2008 #3
    OK. I think I know what g and h are (gravity and height) but the rest I am clueless so ifyou could just explain further it would be appreciated.

    thanks stewartcs.
  5. Aug 29, 2008 #4


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    P1 is the pressure at the top of the tank.
    P2 is the pressure at the bottom of the tank.

    If the tank is open to atmosphere and discharges to atmosphere the equation will obviously reduce. If not, use P1 and P2 as applicable.

    h is the height from the top of the fluid in the tank to the centerline of the orifice.

    A1 is the area of the tank.
    A2 is the area of the orifice (outlet).

    g is gravitational acceleration.

    [tex] \rho [/tex] is the fluid's density.

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