Civil Engineering - Hydraulics - Discussion

Discussion Forum : Hydraulics - Section 5 (Q.No. 1)
1.
Water flows through a convergent mouthpiece of diameter 4 cm at convergence under a head of 3 metres. If the maximum vacuum pressure is 9 metres of water, the maximum diameter of divergence, to aviod separation of flow, is
4 cm
6 cm
2 cm
23 cm.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
9 comments Page 1 of 1.

Devika said:   5 years ago
Please explain this.

SUMANTA DEY said:   6 years ago
Answer is 4√2.
a1/a2= √(1+ HV/H).

a1 =area of diverging.
a2=area of converging(4 cm dia given).

H(atmosphere)- H(absolute at vena contracta) = Hv = 9m.
H = head of liquid over the mouth piece = 3m.

Meera said:   7 years ago
a/ao = √1 + (Ho-Hc) /H.

In question (Ho-Hc) = 9,
So √ 1+9/3,
√ 4 = 2,
I.e., ao/a = (π/4)*(4 square) /(π/4)*(d^2).
LHS = RHS.
16/d^2 = 2.
But I am getting 2 √2.

Please anyone clear my doubt.
(1)

Saurav said:   7 years ago
Anyone can explain me clearly?

Saeed said:   7 years ago
Anybody explain this please.

Garry said:   8 years ago
@Jiren.

In the answer there should be a sign of unroot also.

Mallu said:   8 years ago
Explain clearly.

Jiren said:   8 years ago
Use this formula.


a1/a2= (1+(Ho-Hc)/H) after putting the given values the answer is 2cm.

Parth vyas said:   8 years ago
Please explain it.

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