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How to use Bernoulli's Equation Correctly?

  1. Oct 12, 2006 #1
    One large pipe is splitted into 2 smaller pipes. Can we use Bernoulli's equation and say that the total head at a point in the large pipe is equal to a point at one of the 2 smaller pipes? Why is energy not conserved?
     
  2. jcsd
  3. Oct 13, 2006 #2

    FredGarvin

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    There are 3 main assumptions in the derivation of the Bernoulli equation. What are they?
     
  4. Oct 13, 2006 #3
    energy not conserved cuase of the losses-
    as long as there is a flow then there is a difference in energy-which cuased the flow to occur-
    there is the primary losses(friction)and the secondry(valve,bend-)which u don have here--
    if u could show ur pipe system-it would be more clear for us-
    wish i could help
     
  5. Oct 14, 2006 #4
    Hi Fred,

    Good hints. Check my answers and let me know if I got all of them! :smile:
    1) Constant mass flow rate (no surges).
    2) Frictionless (no heat transfer).
    3) Irrotational (translational velocity only).

    How'd I do?
    Rainman
     
  6. Oct 14, 2006 #5

    FredGarvin

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    They are:
    - Incompressible
    - Inviscous
    - Steady State
    Since it also is applied along the streamline, so the irrotational part holds too.
    A+ for Rainman

    As for the main post, energy will not be conserved because of the losses due to friction. Also, you do not state the fluid involved. If it is a liquid, then the incompressibility assumption is pretty much valid. If it is a gas, you need to be concerned with it.
     
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