Correct Answer - Option 2 : four times
Explanation:
The darcy-Weisbach formula for head loss due to friction is,
\(h_f = \dfrac{4flV^2}{2gd}\)
where, f = Darcy's coefficient of friction, l = length of the pipe, v = velocity of the fluid in the pipe, d = diameter of the pipe.
From the above, hf ∝ V2
Calculation:
Given:
V1 = V, V2 = 2V
\(\frac{h_1}{h_2}=(\frac{V_1}{V_2})^2\)
\(\frac{h_1}{h_2}=(\frac{V}{2V})^2\)
\(\frac{h_1}{h_2}=\frac14\)
h2 = 4h1
