Free Fluid Flow Operations MCQs with Answers

• A. Length & discharge
• B. Head & discharge
• C. Length & diameter
• D. Friction factor & diameter

Explanation: Two pipe systems are hydraulically equivalent when they carry the same discharge with the same head loss.

• A. FL-2T, ML-1T-1
• B. FLT, ML-1T-1
• C. ML-1T-3, F-1L2T
• D. F-1L2T-1, MLT-3

Explanation: Dynamic viscosity has dimensions ML^-1T^-1. Since F = MLT^-2, this is also equivalent to FL^-2T, so both expressions in option a represent…

• A. U-tube manometer
• B. None of these
• C. Pitot tube
• D. Inclined tube manometer

Explanation: An inclined-tube manometer magnifies the vertical movement of the manometric liquid along a longer inclined length, making it sensitive to…

• A. Is constant along a stream line
• B. Relates velocity and pressure
• C. Is constant along an equipotential surface
• D. None of these

Explanation: For two-dimensional flow, the stream function has the same value at every point on a streamline, so a streamline is a constant-ψ line.

• A. Conditions change steadily with time
• B. Conditions are the same at the adjacent points at any instant
• C. Conditions do not change with time at any point
• D. Rate of the velocity change is constant

Explanation: Steady flow means that properties such as velocity, pressure and density at a fixed point do not change with time.

• A. Fluid momentum is constant
• B. Rate of mass outflow is equal to the rate of mass inflow
• C. Force per unit mass equals acceleration
• D. None of these

Explanation: Euler's equation is the inviscid-fluid form of Newton's second law, stating that the resultant force per unit mass equals acceleration.

• A. Directly as square of gas density
• B. Inversely as gas density
• C. Directly as square root of gas density
• D. Directly as gas density

Explanation: At fixed speed and volumetric capacity, the fan's pressure rise scales with dynamic pressure, ρv², while power scales as pressure times…

• A. Pipe length
• B. Ratio of pipe diameter to orifice diameter
• C. Type of orifice & the Reynolds number
• D. Pipe diameter

Explanation: An orifice-meter discharge coefficient depends mainly on the diameter ratio, orifice design and Reynolds number.

• A. Constant
• B. Independent of time
• C. Both A. & B.
• D. Neither A. nor B.

Explanation: In the standard basic-fluid-mechanics use of streamline flow, the motion at a fixed point is treated as steady, so velocity is constant…

• A. Long pipe at constant rate
• B. Expanding tube at increasing rate
• C. Long pipe at decreasing rate
• D. Expanding tube at constant rate

Explanation: Uniform flow means the flow variables do not change along the pipe, while unsteady flow means they change with time.

• A. Same as the average velocity through channels
• B. More than the average velocity through channels
• C. Dependent on the pressure drop across the bed
• D. Less than the average velocity through channels

Explanation: Superficial velocity is calculated using the total bed cross-sectional area, whereas channel velocity uses only the void area.

• A. Delivers unit discharge at unit head
• B. Requires unit power for unit head
• C. Delivers unit discharge at unit power
• D. None of these

Explanation: Specific speed is the speed of a geometrically similar pump that would deliver unit discharge against unit head.

• A. 2 to 5
• B. 7 to 15
• C. 15 to 25
• D. >25

Explanation: The divergent exit cone of a Venturimeter is kept at a small angle to prevent flow separation and excessive energy loss.

• A. rpm
• B. Impeller blade angle
• C. Type of casing
• D. Number of blades in impeller

Explanation: Centrifugal pumps are commonly classified by casing arrangement, such as volute or diffuser casing.

• A. Evaporation
• B. Stripping
• C. Sublimation
• D. Cavitation

Explanation: When pressure falls, dissolved gases can come out of solution and form gas pockets in the pump, a phenomenon treated as cavitation or…

• A. Galileo
• B. Brinkman
• C. Archimedes
• D. Euler

Explanation: The Galileo number measures the relative importance of gravitational and viscous effects and is commonly expressed through Reynolds and…

• A. Density of the fluid
• B. Density of the body
• C. Velocity of the body
• D. Projected area of the body

Explanation: Drag depends on fluid density, relative velocity, projected area and drag coefficient, but not directly on the body's density.

• A. ML-2T-1
• B. L2T-1
• C. ML-2T-2
• D. None of these

Explanation: Kinematic viscosity is dynamic viscosity divided by density, so its dimensions are (ML⁻¹T⁻¹)/(ML⁻³) = L²T⁻¹.

• A. Radius of
• B. Speed of
• C. Fluid velocity leaving
• D. None of these

Explanation: The Euler head relation contains impeller speed, impeller radius and the tangential component of fluid velocity leaving the impeller.

• A. At rest
• B. Frictionless and at rest
• C. At rest and when the frictionless fluid is in motion
• D. None of these

Explanation: Pascal's law is a hydrostatic principle stating that pressure applied to a confined fluid at rest is transmitted undiminished in all…