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Bernouilli's law

  1. Aug 10, 2008 #1
    According to Bernouilli's law there is a direct relation between pressure drop and fluid's velocity at the throat. What would be the physical meaning of a high value negative absolute pressure that theoretically can be achieved by increasing fluid's throat velocity.
  2. jcsd
  3. Aug 28, 2008 #2
    It would probably mean that the pressure experienced before the throat is increased,

    In the eq P1 + 1/2DV1^2 = -P2 + 1/2DV2^2,
    bring _p2 to the other side

    =>P1+P2 + 1/2DV1^2 = 1/2DV2^2

    (D=density,P1 = initial press.,P2=final pressure,same for V1 and V2)

    implying that the original pressure is increased.....
    Hope you understand what Im trying to say.....(good question though)
  4. Aug 28, 2008 #3


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    It is nonsensical since absolute pressures cannot be negative.

  5. Aug 28, 2008 #4


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    Absolute limit of velocity in any throat is going to be sonic velocity. There's your limit right there.
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