Friction loss in pipe

  • Thread starter foo9008
  • Start date
  • #1
678
4

Homework Statement


the major loss in the fluid due to pipe friction is f(L)(v^2) / 2gD , (darcy weisbech equation)

why the author use 4fL(V^2) / 2gD ? in the equation ? is it wrong ?

Homework Equations




The Attempt at a Solution

 

Attachments

  • 209.PNG
    209.PNG
    53.8 KB · Views: 352

Answers and Replies

  • #2
232
53
Hi! The Darcy-Weisbach equation is written in terms of the Darcy friction factor (fD), whereas the second equation you posted is probably written in terms of the Fanning friction factor (fF), which is weird, because the problem provides the Darcy factor. The relationship between them is fD = 4fF, so both equations are correct depending on the friction factor you use. However, in your example, they just plugged in the 0.008, so yeah, there is something wrong with the calculation or the problem statement. This is actually a pretty common mistake. Is that from a textbook?

As a generalization, the Darcy friction factor is commonly used in mechanical engineering calculations, while the Fanning factor is used in chemical engineering calculations.
 
Last edited:

Related Threads on Friction loss in pipe

Replies
9
Views
735
Replies
7
Views
910
  • Last Post
2
Replies
33
Views
2K
  • Last Post
Replies
17
Views
784
  • Last Post
Replies
10
Views
1K
  • Last Post
Replies
3
Views
557
  • Last Post
Replies
6
Views
732
  • Last Post
Replies
12
Views
1K
  • Last Post
Replies
0
Views
4K
  • Last Post
Replies
1
Views
483
Top