1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Quick question about Bernoulli principle and resistance?

  1. Feb 12, 2010 #1
    Ok I studied bernoulli and I can see how fluid would travel faster in narrowed regions but in most examples I see when something is narrowed the flow is reduced. Is this because of resistance? Also when there is resistance speed in the narrowed section is reduced right? I like to know what do they mean by this friction. Simply I'm asking in most occasion when something is narrowed the fluid flows slower due to resistance. It might be faster than non narrowed part but it is slow because of resistance(I mean if there was no resistance it would be faster) Is that right?
  2. jcsd
  3. Feb 12, 2010 #2


    User Avatar

    Staff: Mentor

    This must be the 5th time you have asked this same question. The answer hasn't changed: Bernoulli's equation deals with ONE flow scenario at a time. When you take a pipe with a certain flow and pinch it, the Bernoulli description you were just using is no longer valid.
  4. Feb 12, 2010 #3
    Yes you are right I'm sorry for repetition but I still haven't grasped this. Ok now from what you have said this is my new understanding tell me if this is right.

    Non narrowed area------> narrowed area

    Let's say fluid is flowing in a pipe and I suddenly narrowed it. Then I can understand how this would create a restriction and higher pressure in the non narrowed area. Does this higher pressure account for higher pressure loss so there is less force for fluid to move. I want to know if the pressure loss occurs in the non narrowed area due to the restriction or in the narrowed area due the walls coming very close? Thank you!! :smile:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook