Fluid Mechanics and Hydraulic Machinery Miscellaneous
 For a fully developed flow through a pipe, the ratio of the maximum velocity to the average velocity is _________(fill in the blanks)

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Two
Correct Option: A
Two
 The discharge in m^{3} / s for laminar flow through a pipe of diameter 0.04 m having a centre line velocity of 1.5 m/s is

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u_{max} = 2 u_{avg}
u_{max} = 2 u_{avg}
1.5 = 2u_{avg}u_{avg} = 1.5 m /s 2
Q = A × V = A × u_{avg}Q = π d^{2} × u_{avg} 4 = π × (0.04)^{2} × 1.5 = 3π m^{3} /s 4 2 10000
Correct Option: D
u_{max} = 2 u_{avg}
u_{max} = 2 u_{avg}
1.5 = 2u_{avg}u_{avg} = 1.5 m /s 2
Q = A × V = A × u_{avg}Q = π d^{2} × u_{avg} 4 = π × (0.04)^{2} × 1.5 = 3π m^{3} /s 4 2 10000
 Shown below are three tanks, tank 1 without an orifice tube and tanks 2 and 3 with orifice tubes as shown. Neglecting losses and assuming the diameter of orifice to be much less than that of the tank, write expressions for the exit velocity in each of the three tanks.

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V_{1} = √2gH
V_{2} = √2g(H + L)
V_{3} = √2g(H + L)Correct Option: D
V_{1} = √2gH
V_{2} = √2g(H + L)
V_{3} = √2g(H + L)
 Consider steady flow of water in a situation where two pipe lines (pipe 1 and pipe 2) combine into a single pipe line (pipe 3) as shown in figure. The crosssectional'area of all three pipelines are constant. The following data is given
Assuming the water properties and the velocities to be uniform across the crosssection of the inlets and the outlet, the exit velocity (in m/s) in pipe 3 is

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Q1 + Q2 = Q3
A_{1}V_{1} + A_{2}V_{2} = A_{3}V_{3}
1 + 4 = 2.5 V_{3}
or V_{3} = 2 m/sCorrect Option: C
Q1 + Q2 = Q3
A_{1}V_{1} + A_{2}V_{2} = A_{3}V_{3}
1 + 4 = 2.5 V_{3}
or V_{3} = 2 m/s
 As the transition from laminar to turbulent flow is induced in a cross flow past a circular cylinder the value of the drag coefficient drops.

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True
Correct Option: B
True