Free Fluid Flow Operations MCQs with Answers

• A. 2000
• B. 10
• C. 100
• D. 1000

Explanation: Using Re = ρvD/μ for water, Re ≈ (1000)(0.05)(0.02)/(0.001) = 1000. Thus the nearest option is 1000.

• A. Dependent on the length of the pipe
• B. Independent of Reynolds number
• C. Dependent on Reynolds number
• D. None of these

Explanation: Equivalent length represents the length of straight pipe having the same pressure loss as a fitting, and the loss depends on the flow…

• A. Incompressible, frictionless, steady, along a streamline
• B. Uniform, steady, incompressible, along a streamline
• C. Steady, density being pressure dependent, frictionless
• D. None of these

Explanation: Bernoulli's equation in its basic form assumes steady, incompressible, frictionless flow along a streamline.

• A. Booster service
• B. All A., B. and C.
• C. Pumping industrial wastes
• D. Pumping liquid fertilisers (e.g. liquid NH3)

Explanation: Self-priming centrifugal pumps can evacuate air from the suction line and are therefore useful in booster service, liquid fertiliser…

• A. 500
• B. 200
• C. 1000
• D. 750

Explanation: The centrifugal-pump affinity law gives Q proportional to speed when the impeller diameter is unchanged.

• A. 4.728
• B. 0.5
• C. 0.622
• D. 0.474

Explanation: Nominal pipe size is not the actual inside diameter, because schedule changes wall thickness.

• A. Centrifugal
• B. Reciprocating
• C. Gear
• D. Screw

Explanation: Centrifugal pumps are commonly used for slurries because they can handle large flow rates and suspended solids with relatively simple…

• A. Multiplying with density (gm/c.c)
• B. Dividing by density (gm/c.c)
• C. Multiplying with specific gravity
• D. Dividing by specific gravity

Explanation: Kinematic viscosity is related to dynamic viscosity by ν = μ/ρ, so poise is divided by density in g/cm³ to obtain stokes.

• A. Thickness only
• B. Outer diameter only
• C. Thickness & outer diameter both
• D. Inner diameter

Explanation: A tube is conventionally identified by its outside diameter and wall thickness, from which the inside diameter can also be calculated.

• A. Head loss is the same through each pipe
• B. Discharge is the same through all the pipes
• C. Total head loss is equal to the sum of the head losses through each pipe
• D. None of these

Explanation: Branches connected in parallel have the same pressure drop, and therefore the same head loss between their common junctions.

• A. 0.44
• B. 0.044
• C. 4.4
• D. 44

Explanation: In the Newton or high-Reynolds-number range, the drag coefficient of a smooth spherical particle is approximately 0.44.

• A. D Δp/8L
• B. D Δp/4L
• C. 8 Vavg/D
• D. 4 Vavg/D

Explanation: For laminar pipe flow, the wall shear rate is the velocity-gradient magnitude at the wall, equal to 8Vavg/D.

• A. Logarithmic
• B. Hyperbolic
• C. Parabolic
• D. Linear

Explanation: The Hagen-Poiseuille velocity profile is u = umax[1 − (d/R)²], so velocity varies parabolically with distance from the centreline.

• A. d
• B. d2
• C. d4
• D. d̅ 2

Explanation: In the viscous, low-Reynolds-number part of packed-bed flow, the Ergun relation contains the particle-size dependence 1/d².

• A. Rotameter
• B. Orificemeter
• C. Venturimeter
• D. Flow nozzle

Explanation: A rotameter has a variable-area passage and can measure small gas flow rates with relatively low pressure loss.

• A. Shear stress and velocity
• B. Shear stress and rate of angular deformation in a fluid
• C. Velocity gradient and pressure intensity
• D. Pressure gradient and rate of angular deformation

Explanation: Newton's viscosity law states that shear stress is proportional to the rate of angular deformation, equivalently the velocity gradient, in…

• A. Exponentially decrease
• B. Decrease
• C. Not change
• D. Increase

Explanation: At a fixed volumetric flow rate, supplying more horsepower to a centrifugal compressor allows it to develop a greater pressure rise, so…

• A. Pitot tube
• B. Rotameter
• C. Venturimeter
• D. Flow nozzle

Explanation: A Pitot tube measures stagnation or impact pressure and compares it with static pressure; their difference gives the velocity pressure…

• A. Centrifugal
• B. Plunger
• C. Piston
• D. Vane

Explanation: A plunger pump is a positive-displacement pump designed for very high discharge pressures because its reciprocating plunger can generate…

• A. Dynamic
• B. Total
• C. Static
• D. None of these

Explanation: A static tube is aligned so that it does not convert the fluid's motion into a pressure rise, allowing it to sense the local static…