Page 129 - ebook fluid mechanics_finalize

FLUID MECHANICS

5.3.2 Pipe in series

(v − v ) 2
Loss at enlarg ement = 1 2
2 g

Figure 5.7 : Pipe in series

Example 5.5

Water is discharged from a reservoir into the atmosphere through a pipe 39 m long
(Figure 5.7). There is a sharp entrance to the pipe and the diameter is 50 mm for the first

15 m from the entrance. The pipe then enlarges suddenly to 75 mm in diameter for the

remainder of its length. Taking into account the loss of head at entry and at the

enlargement, calculate the difference of level between the surface of the reservoir and
3
the pipe exit which will maintain a flow of 2.8 dm /s. Take f as 0.0048 for the 50 mm pipe
and 0.0058 for the 75 mm pipe.

118