Fluid Mechanics

621.Upto what value of 'Mach number', a fluid may be considered as incompressible?

1. 0.03
2. 0.3
3. 3
4. 10

622.Vane anemometer

1. Is an area meter
2. Is a variable head meter
3. Rotates an element at a speed determined by the velocity of the fluid in which the meter is immersed
4. None of these

623.Various efficiencies of a centrifugal pump are related as (where, ε_m = mechanical efficiency ε_v = volumetric efficiency. ε_ma = manometric efficiency ε_o = overall efficiency)

1. η_ma × η_m × η_v = η_o
2. η_m = η_v . η_ma
3. η_ma = η_m × η_v
4. η_v = η_m × η_ma

624.Velocity at a certain point in case of streamline flow is

1. Constant
2. Independent of time
3. Both (A) & (B)
4. Neither (A) nor (B)

625.Velocity distribution for flow between two fixed parallel plates

1. Varies parabolically across the section
2. Is constant over the entire cross-section
3. Is zero at the plates and increases linearly to the mid-plane
4. None of these

626.Velocity head on sudden enlargement in a horizontal pipe is converted into _________ head.

1. Elevation
2. Pressure
3. Both (A) & (B)
4. Neither (A) nor (B)

627.Velocity of liquid hydrocarbon fuels in a pipeline cannot be measured by magnetic flowmeters, because their _________ is very low/small.

1. Thermal conductivity
2. Electrical conductivity
3. Specific gravity
4. Electrical resistivity

628.Vena-contracta formed during flow of a liquid through an orificemeter has

1. Minimum liquid cross-section
2. More diameter compared to orifice diameter
3. Minimum velocity of fluid stream
4. None of these

629.Vena-contracta pressure tapping is at a distance _________ from the position of an orificemeter fitted in a pipe of internal diameter 'd'

1. d
2. 0.5 d
3. 2d
4. 4d

630.Venturimeter and orificemeter measures the _________ of the fluid.

1. Pressure
2. Maximum velocity
3. Average velocity
4. Point velocity