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Fluid Mechanics Confusion

  1. Dec 10, 2011 #1

    Recently performed a very basic fluid mechanics experiment with water flowing at different speeds through a Venturi Rig. Most of it went as expected, total head stayed roughly the same throughout but slightly decreased from flow loss due to resistant forces.

    However, at certain random points the total head would increase further along the Venturi.

    I know it is most probably imperfect experimentation technique. What could have caused this increase in the total head further along the pipe?? I'm a bit confused.

    Thanks in advance for any light that can be shed on this.
  2. jcsd
  3. Dec 10, 2011 #2
    How much did it change? If it is a very small amount you should check it against the uncertainty in your measurement technique.

    If the change is not small, does it correlate with anything like the flow speed?

    A potential cause could be the turbulence level in your flow. Turbulent velocity fluctuations can cause a total pressure probe to read a pressure that is actually higher than the true mean total pressure.
  4. Dec 10, 2011 #3
    thanks man, that helps
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