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Homework Help: Fluids - variation of velocity for free jets

  1. Sep 13, 2006 #1
    hey guys, only my second post here, hope these boards are helpful!

    I have a problem for my fluid mechanics class and was wondering if anyone could help me out. i will post the question and the figures and what assumptions i have made due to the lack of information.

    Several holes are punched into a tin can as shown in Fig. P3.17. Which of the figures represents the variation of the water velocity as it leaves the holes? Justify your choice.
    The figures are attached below.

    I have assumed that all of the holes are teh same size and are not smooth/curved as i would suspect a drill would leave them upon pushing the material inwards towards its vertical z-axis of symmetry. if the holes aren't smooth/curved, they have 90 degree corners which gives the exiting fluid the vena contracta effect...

    I know velocity is a direct function of the size of the holes and the pressure gradient (dp/dr). the pressure is dependent upon the depth of each hole, so this means that the velocity vectors should be like those in C which increase more over depth in a fashion that we would expect them to, right? if the answer isn't C, then it would have to be B, but i'm so confused now that it could be either one of them.

    hope someone knows more about fluids than myself!

    Attached Files:

  2. jcsd
  3. Sep 13, 2006 #2
    oh, of course i have assumed steady, incompressible, inviscid flow!
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