Question

Two pipe systems are said to be equivalent when

• A. They carry same discharge
• B. They are satisfying Bernoulli's theory
• C. Both have same head loss and discharge values
• D. They are of same length and having same head loss
  

Answer 1

The correct option is C Both have same head loss and discharge values

A hydraulically equivalent pipe means a pipe which can replace existing compound pipe network carrying same discharge under same head losses.


Neglecting minor losses, (and assuming 'f' to be same)

$\frac{fL{Q}^2}{12.1D^5}=\frac{f{L}_1{Q}^2}{12.1D_1^5}+\frac{f{L}_2{Q}^2}{12.1D_2^5}+\frac{f{L}_3{Q}^2}{12.1D_3^5}$

Thus, for equivalent pipe we have

$\frac{L}{D^5}=\frac{L_1}{D_1^5}+\frac{L_2}{D_2^5}+\frac{L_3}{D_3^5}$