Free Fluid Flow Operations MCQs with Answers

• A. None of these
• B. At higher temperatures
• C. Only in Newtonian fluids
• D. Where there is no velocity gradient

Explanation: Isotropic turbulence has statistically equal properties in all directions and is associated in basic treatments with regions having…

• A. Dynamic similarity
• B. Same efficiency
• C. Same speed
• D. Geometrical similarity

Explanation: Specific speed is a similarity parameter used to compare pumps under dynamically similar operating conditions.

• A. √(2gh)
• B. C.V. √(2gh)
• C. Cd √(2gh)
• D. Cc √(2gh)

Explanation: The ideal velocity from the reservoir head is √(2gh), while the actual velocity is reduced by the coefficient of velocity, Cv.

• A. Bearing losses
• B. Disk friction
• C. Shock losses
• D. Cavitation

Explanation: A diffuser pump uses diffuser vanes to recover pressure from the impeller discharge smoothly.

• A. d
• B. 4d
• C. 2d
• D. 0.5 d

Explanation: For a standard orifice meter, the vena contracta is located approximately 0.5 pipe diameters downstream of the orifice plate.

• A. Is independent of the specific weight of the fluid
• B. Lies above the centroid of the plane surface
• C. Is different for different fluids
• D. Is at the centroid of the plane surface

Explanation: For a vertical plane surface, the centre of pressure lies below the centroid because pressure increases with depth.

• A. Vacuum as well as the atmospheric
• B. Absolute
• C. Difference in
• D. Gage

Explanation: A manometer balances the pressure difference between its connected points through the hydrostatic head of a manometric liquid.

• A. Pressure
• B. Average velocity
• C. Average flow rate
• D. Point velocity

Explanation: A Pitot tube brings the fluid at a point to rest and uses the resulting stagnation pressure to calculate the velocity at that point.

• A. More
• B. Less
• C. Equal
• D. More or less, depending on the type of particle

Explanation: In hindered settling, neighbouring particles obstruct the fluid flow and increase resistance to particle motion.

• A. High suction pressure
• B. Low suction pressure
• C. Low barometric pressure
• D. High suction velocity

Explanation: Cavitation occurs when the local liquid pressure falls below its vapour pressure, causing vapour bubbles to form and collapse.

• A. Powder & granular solids
• B. Liquids
• C. All A, B & C
• D. Low melting point semi-solids

Explanation: A pycnometer determines density or specific gravity from a known volume and mass, so it can be adapted for liquids, powders and granular…

• A. Cold
• B. Static
• C. Moving
• D. Hot

Explanation: Pressure is equal in all directions at a point only for a fluid at rest.

• A. Absolute viscosity
• B. Reynolds number
• C. Density
• D. Ratio of absolute viscosity to density

Explanation: Gravity-driven flow through a viscometer is governed primarily by kinematic viscosity, which is the ratio of absolute viscosity to…

• A. Froude number
• B. Reynolds number
• C. Mach number
• D. All A., B. and C.

Explanation: For an incompressible fluid around a body, drag and lift coefficients are commonly correlated with Reynolds number, which compares…

• A. Incomplete priming
• B. Too high a suction lift
• C. All A., B., and C.
• D. Low available NPSH and air leaks in the suction pipe

Explanation: A centrifugal pump can lose prime through incomplete priming, excessive suction lift, or air entry and inadequate NPSH in the suction…

• A. Weir
• B. None of these
• C. Cup and vane anemometer
• D. Hot wire anemometer

Explanation: A hot-wire anemometer determines fluid velocity from the cooling effect of the flowing fluid on a heated wire, and it can be used to…

• A. Surface tension
• B. Height of descend
• C. Viscosity
• D. Pressure

Explanation: Surface tension pulls the liquid surface inward and minimises surface area, causing small falling drops to become nearly spherical.

• A. 0.5
• B. 1
• C. 2
• D. 0.33

Explanation: In the Stokes regime, viscous or wall drag contributes two-thirds of the total drag on a sphere, while form or pressure drag contributes…

• A. Co-efficient of contraction only
• B. Its orientation
• C. Pressure drop only
• D. None of these

Explanation: For a fixed Venturimeter, the measured pressure drop is used to calculate discharge, so pressure drop is the relevant operating…

• A. (V12 - V22)/2gc
• B. (V12 - V22)/gc
• C. (V1 - V2)/2gc
• D. (V1 - V2)2/2gc

Explanation: A sudden expansion produces an irreversible loss due to eddies and mixing, given by hL = (V1 − V2)^2/(2gc) in the stated notation.