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Water flow discharge

  1. Oct 31, 2005 #1
    I've got two tubes filled with liquid, their both of equal diameters, the first one is straight up and down about 20 feet long, the other is 100 feet long but is spiraled like on a spool, since the straight tube has a higher fall than the spiral, I would assume that the straight tube would have more pressure.
    Is my thinking correct?
  2. jcsd
  3. Oct 31, 2005 #2


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    Hi Pragmatic. Yes, your answer is correct. If there is no flow in the tubes (the fluid is static) then the only thing pressure at the bottom of the tube is dependant on is "head" or the height of the fluid. It is also independant of the diameter, length and shape of the tube. Pressure at the bottom is simply the density times gravity times height plus whatever pressure there is at the top of the fluid, it's that simple.
  4. Oct 31, 2005 #3


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    What pressure are you referring to? The static pressure at the bottom of the tube? Are the tops and bottoms of the tubes at the same heights? Are both tubes filled with the same liquid to the same level?
  5. Oct 31, 2005 #4
    Perhaps pressure is not the right discription, I should of probably said force?
    The spiral is lower, but both are even at the bottom.
    Both have water, but the spiral since it is 100 foot long it would have that much more water.
  6. Oct 31, 2005 #5


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    No. Pressure is the correct term. After what you have mentioned, Q's reply is the appropriate one. As he mentioned, the pressure head is going to be only dependent on the height of the water, not the amount.
  7. Oct 31, 2005 #6
    thanks, may have another question on
    this later.
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