451. The ratio of the hydraulic radius to the diameter of the channel, for maximum mean velocity of flow in a circular channel, in open channel flow is
0.3
0.9
0.03
0.66
✅ The correct answer is option A.
Fluid Mechanics MCQs
452. A piezometer provided in the pipe measures
Friction factor
Static pressure
Dynamic pressure
None of these
✅ The correct answer is option B.
453. A Newtonion liquid (ρ = density, μ = viscosity) is flowing with velocity v in a tube of diameter ‘D’. Let Δp be the pressure drop across the length ‘L’. For a laminar flow, Δp is proportional to
L ρv²/D
L μ;V/D²
D ρv²/L
Μ V/L
✅ The correct answer is option A.
454. Specific speed for a centrifugal pump is
N√Q/H3/4
N√Q/H2/3
N√Q/H1/4
N√Q/H
✅ The correct answer is option A.
455. The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is
0.5
1
1.5
2
✅ The correct answer is option D.
456. Horsepower requirement for given pump capacity depends upon the
Specific gravity of the liquid
Suction lift
Discharge head
All of the above
✅ The correct answer is option D.
457. The fluid property which matters for fall-ing rain drops to acquire spherical shape is its
Pressure
Height of descend
Viscosity
Surface tension
✅ The correct answer is option D.
458. Fanning friction factor is equal to(where, fB = Blassius friction factor).
fB/4
fB/2
4fB
2fB
✅ The correct answer is option A.
459. Water is flowing at 1 m/sec through a pipe (of 10 cm I.D) with a right angle bend. The force in Newtons exerted on the bend by water is
10√2π
5π/2
5√2π
5π/√2
✅ The correct answer is option B.
460. Prandtl number is a measure of the
Heat conduction to viscosity of a fluid
Cp/Cv of a fluid
Elastic force to pressure force in the fluid flow
Inertial force to elastic force in the fluid flow
✅ The correct answer is option A.