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!

Friction loss is significant in short pipe

  1. Apr 8, 2016 #1
    1. The problem statement, all variables and given/known data
    i was told that the friction loss is significant in short pipe , but not so significant in long pipe . However , the friction formula is given by formula f(L/D)(V^2)/2g , as L is big , friction loss is big . so the friction loss is big , right ?

    2. Relevant equations


    3. The attempt at a solution
     
  2. jcsd
  3. Apr 8, 2016 #2

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    I wouldn't always be so credulous of what "somebody" tells you. Friction loss depends not only on L/D, but also V.
     
  4. Apr 8, 2016 #3
    it was written in a book .... why the friction loss due to entrance effect is significant in short pipe , but not so significant in long pipe ????
     

    Attached Files:

  5. Apr 8, 2016 #4

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Well, why do you think this situation would be so?

    What is the relative loss due to entrance effect compared with the loss in a section of straight pipe?

    Note: Your original post mentioned only friction losses. Now, you are talking about losses due to entrance effects. It's important to disclose all information at the start of a discussion to prevent misunderstandings.
     
  6. Apr 8, 2016 #5
    sorry , i mean friction due to entrance effect . why it is negligible in long pipe ? the friction formula is given by formula f(L/D)(V^2)/2g , as L is big , friction loss is big . so the friction loss is big , right ?
     
  7. Apr 8, 2016 #6

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    So, if the friction loss in a long pipe is relatively large, what about the ratio of the entrance loss to the friction loss in the long pipe? Is it a large ratio or a small ratio?
    Is the entrance loss affected by the length of the pipe to which it is applied?
     
  8. Apr 8, 2016 #7
    if the friction loss in a long pipe is relatively large, the ratio of the entrance loss to the friction loss in the long pipe woul be small , ?
    due to this reason , the friction loss due to entrance effect is negligible ?
     
  9. Apr 9, 2016 #8

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    In a long pipe.

    How would the friction loss due to the entrance effect compare to the friction loss in a short pipe?
     
  10. Apr 9, 2016 #9
    the friction loss in short pipe is small , so the friction due to entrance effect is significant in short pipe compared to the friction loss in short pipe??????
     
  11. Apr 9, 2016 #10

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Yes.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Friction loss is significant in short pipe
  1. Friction loss (Replies: 7)

Loading...