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Working out the load applied to anchors used to hold a car stationary in a river.

  1. Feb 8, 2012 #1

    I am trying to work out the load applied to some anchors used to hold a car stationary in a man made river channel. I know it will be something to do with the surface area and the speed/volume of water. Can anyone help, admittedly I am a practical person not a acaedamic so layman terms please.

  2. jcsd
  3. Feb 9, 2012 #2
    So I have a car side ways on to a flow of water moving around 15mph, I imagine there is around 5 square meters of surface area that the water hits, how much load will be applied to the anchor holding the car in the channel.
  4. Feb 9, 2012 #3
    You have mixed imperial and metric units, but I am going to work in imperial.

    The maximum possible force is larger than you might think and is given by

    [tex]F = \frac{{wa{v^2}}}{g}[/tex]

    F is the force in lbs,
    w is the weight of water in lbs per cubic foot = 62.4 lbs per cubic foot
    a = wetted area of car = 54 square feet
    v is the velocity in feet per second = 22 feet per second
    g is the acceleration due to gravity = 32 feet per second per second

    F = 62.4*54*22*22/32 = 51,000 lbs

    Max pressure would be F/a = 944 lbs per square foot or 6.5 psi or about half an atmosphere.

    go well
    Last edited: Feb 9, 2012
  5. Feb 10, 2012 #4

    yeah its a complicated situation because buoyancy also affects the car, the heavier the car the more friction it is subjected to on the river channel, reducing the load, thanks for you time

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