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Homework Help: Constant liquid pressure device

  1. May 7, 2006 #1
    I was wondering if anyone could point me towards a source about making constant head devices. I was wanting to measure and then relate, experimentally, the velocity of a stream to its cross-sectional area. Since this will be done mostly at home using pedestrian tools, I need to find out how I can make a device to allow me to have constant pressure for my stream.

    I was thinking of a bucket with one inlet and two outlets, but I'm not quite sure if that would work.

    Thanks for your help
  2. jcsd
  3. May 7, 2006 #2
    An addendum. I intend to measure the cross sectional area of the stream using the shadows it casts on a surface, since measuring the stream diameter would be very hard.

    However, here I encounter another problem, the shadows become indistinct as I cast them on the wall, and are useless to my measurements.
  4. May 8, 2006 #3
    You should be able to use a bucket to create a stream with constant head. Just fill the bucket up and put a running hose in it. Then you can have a tube coming out the bottom and as long as there is more water going into the bucket than coming out (ie. the bucket is overflowing or at least staying at the same level) you will have a source of water at constant head.
  5. May 8, 2006 #4


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    Homework Helper

    You can use a lens to form an image of the stream and then measure the diameter on the image. Use the magnification to convert this to the real diameter. If you work at 2f for both image and object distance the magnification is x1.
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