Page 100 - ebook fluid mechanics_finalize

FLUID MECHANICS

From Bernoulli’s Equation,

Total energy at section 1 = Total energy at section 2

p 1 + v 1 2 = p 2 + v 2 2 ——————(1)
 2 g  2 g

v 2 2 − v 1 2 = p − p 2 ——————(2)
1
2g 

z1 = z2 because the two parts are at the same level

We know that, Q = A v

For continuity of flow, Q1 = Q2

or

A1v1 = A2v2

A v
v2 = 1 1 ——————(3)
A 2

Putting (3) into (2),

v 2 2 − v 1 2 = p − p 2 ——————(2)
1
2g 

A v
v2 = 1 1 ——————(3)
A 2

Then,

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