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FLUID MECHANICS

Discharge at section 1 = Discharge at section 2

Q = Q
2
1

A v = A v
1 1 2 2

Example 4.4

If the area A1 = 10  10 m and A2 = 3  10 m and the upstream mean velocity, v1=2.1
2
-3
-3
2
m/s, calculate the downstream mean velocity.
Solution to Example 4.4

A v
v = 1 1
2
A 2

10 10 − 3 ( ) 1.2
=
3 10 − 3

7= 0 . m s /

Now try this on a diffuser, a pipe which expands or diverges as in the Figure 4.4 below.

Section 1 Section 2

Figure 4.4

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