30 real Fluid Mechanics & Hydraulics questions from the Civil Core bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Bernoulli's equation?
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A.abrupt rise from supercritical to subcritical depth that dissipates energy, used deliberately as an energy dissipator below spillways and sluices
B.ratio of inertia to gravity forces V/√(gy); open-channel flow is subcritical below 1 and supercritical above 1
C.pressure head plus velocity head plus datum head stays constant along a streamline for steady, incompressible, frictionless flow
D.the gradual converging-diverging venturi has a discharge coefficient near 0.98, while the sharp-edged orifice plate has about 0.62 with far higher head loss
2. Which term means: "pressure head plus velocity head plus datum head stays constant along a streamline for steady, incompressible, frictionless flow"?
A.Bernoulli's equation — distance between the centre of gravity and the metacentre of a floating body; a positive value means the body returns upright after tilting
B.Bernoulli's equation — ratio of inertia to viscous forces ρVD/μ; pipe flow is laminar below 2000 and turbulent above 4000
C.Bernoulli's equation — abrupt rise from supercritical to subcritical depth that dissipates energy, used deliberately as an energy dissipator below spillways and sluices
D.Bernoulli's equation — pressure head plus velocity head plus datum head stays constant along a streamline for steady, incompressible, frictionless flow
A.Reynolds number — abrupt rise from supercritical to subcritical depth that dissipates energy, used deliberately as an energy dissipator below spillways and sluices
B.Reynolds number — pressure surge from sudden valve closure or pump trip, mitigated by slow closure, surge tanks or air vessels on long rising mains
C.Reynolds number — friction head loss in a pipe equals f L V² / (2 g D), with friction factor f read from the Moody chart
D.Reynolds number — ratio of inertia to viscous forces ρVD/μ; pipe flow is laminar below 2000 and turbulent above 4000
A.Froude number — uniform open-channel velocity is (1/n) R^(2/3) S^(1/2), with roughness n about 0.013 for finished concrete
B.Froude number — pressure surge from sudden valve closure or pump trip, mitigated by slow closure, surge tanks or air vessels on long rising mains
C.Froude number — the gradual converging-diverging venturi has a discharge coefficient near 0.98, while the sharp-edged orifice plate has about 0.62 with far higher head loss
D.Froude number — ratio of inertia to gravity forces V/√(gy); open-channel flow is subcritical below 1 and supercritical above 1
11. Which term means: "distance between the centre of gravity and the metacentre of a floating body; a positive value means the body returns upright after tilting"?
A.Metacentric height — energy per unit weight measured above the channel bed, y + V²/2g, which is minimum at critical depth
B.Metacentric height — distance between the centre of gravity and the metacentre of a floating body; a positive value means the body returns upright after tilting
C.Metacentric height — pressure head plus velocity head plus datum head stays constant along a streamline for steady, incompressible, frictionless flow
D.Metacentric height — uniform open-channel velocity is (1/n) R^(2/3) S^(1/2), with roughness n about 0.013 for finished concrete
A.Darcy–Weisbach equation — ratio of inertia to viscous forces ρVD/μ; pipe flow is laminar below 2000 and turbulent above 4000
B.Darcy–Weisbach equation — ratio of inertia to gravity forces V/√(gy); open-channel flow is subcritical below 1 and supercritical above 1
C.Darcy–Weisbach equation — friction head loss in a pipe equals f L V² / (2 g D), with friction factor f read from the Moody chart
D.Darcy–Weisbach equation — distance between the centre of gravity and the metacentre of a floating body; a positive value means the body returns upright after tilting
A.Manning's formula — friction head loss in a pipe equals f L V² / (2 g D), with friction factor f read from the Moody chart
B.Manning's formula — pressure surge from sudden valve closure or pump trip, mitigated by slow closure, surge tanks or air vessels on long rising mains
C.Manning's formula — ratio of inertia to viscous forces ρVD/μ; pipe flow is laminar below 2000 and turbulent above 4000
D.Manning's formula — uniform open-channel velocity is (1/n) R^(2/3) S^(1/2), with roughness n about 0.013 for finished concrete
A.friction head loss in a pipe equals f L V² / (2 g D), with friction factor f read from the Moody chart
B.uniform open-channel velocity is (1/n) R^(2/3) S^(1/2), with roughness n about 0.013 for finished concrete
C.the gradual converging-diverging venturi has a discharge coefficient near 0.98, while the sharp-edged orifice plate has about 0.62 with far higher head loss
D.ratio of inertia to viscous forces ρVD/μ; pipe flow is laminar below 2000 and turbulent above 4000
20. Which term means: "the gradual converging-diverging venturi has a discharge coefficient near 0.98, while the sharp-edged orifice plate has about 0.62 with far higher head loss"?
A.Venturimeter vs orificemeter — distance between the centre of gravity and the metacentre of a floating body; a positive value means the body returns upright after tilting
B.Venturimeter vs orificemeter — the gradual converging-diverging venturi has a discharge coefficient near 0.98, while the sharp-edged orifice plate has about 0.62 with far higher head loss
C.Venturimeter vs orificemeter — friction head loss in a pipe equals f L V² / (2 g D), with friction factor f read from the Moody chart
D.Venturimeter vs orificemeter — ratio of inertia to gravity forces V/√(gy); open-channel flow is subcritical below 1 and supercritical above 1
A.the gradual converging-diverging venturi has a discharge coefficient near 0.98, while the sharp-edged orifice plate has about 0.62 with far higher head loss
B.energy per unit weight measured above the channel bed, y + V²/2g, which is minimum at critical depth
C.ratio of inertia to gravity forces V/√(gy); open-channel flow is subcritical below 1 and supercritical above 1
D.uniform open-channel velocity is (1/n) R^(2/3) S^(1/2), with roughness n about 0.013 for finished concrete
A.Specific energy — uniform open-channel velocity is (1/n) R^(2/3) S^(1/2), with roughness n about 0.013 for finished concrete
B.Specific energy — distance between the centre of gravity and the metacentre of a floating body; a positive value means the body returns upright after tilting
C.Specific energy — energy per unit weight measured above the channel bed, y + V²/2g, which is minimum at critical depth
D.Specific energy — the gradual converging-diverging venturi has a discharge coefficient near 0.98, while the sharp-edged orifice plate has about 0.62 with far higher head loss
26. Which term means: "abrupt rise from supercritical to subcritical depth that dissipates energy, used deliberately as an energy dissipator below spillways and sluices"?
A.Hydraulic jump — uniform open-channel velocity is (1/n) R^(2/3) S^(1/2), with roughness n about 0.013 for finished concrete
B.Hydraulic jump — friction head loss in a pipe equals f L V² / (2 g D), with friction factor f read from the Moody chart
C.Hydraulic jump — abrupt rise from supercritical to subcritical depth that dissipates energy, used deliberately as an energy dissipator below spillways and sluices
D.Hydraulic jump — ratio of inertia to viscous forces ρVD/μ; pipe flow is laminar below 2000 and turbulent above 4000
29. Which term means: "pressure surge from sudden valve closure or pump trip, mitigated by slow closure, surge tanks or air vessels on long rising mains"?
A.Water hammer — pressure surge from sudden valve closure or pump trip, mitigated by slow closure, surge tanks or air vessels on long rising mains
B.Water hammer — ratio of inertia to gravity forces V/√(gy); open-channel flow is subcritical below 1 and supercritical above 1
C.Water hammer — uniform open-channel velocity is (1/n) R^(2/3) S^(1/2), with roughness n about 0.013 for finished concrete
D.Water hammer — distance between the centre of gravity and the metacentre of a floating body; a positive value means the body returns upright after tilting
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