Free Fluid Flow Operations MCQs with Answers

• A. Energy is not constant along a streamline
• B. Net rate of inflow into any small volume must be zero
• C. Energy is constant along a streamline
• D. There exists a velocity potential

Explanation: The continuity equation expresses conservation of mass, so for steady incompressible flow the net rate of inflow into a small control…

• A. Rate of falling of ram
• B. Flow rate through accumulator
• C. Amount of energy stored
• D. Volume available in the cylinder

Explanation: The capacity of a hydraulic accumulator is specified by the maximum energy it can store and release.

• A. Laminar
• B. Uniform
• C. Steady
• D. Unsteady

Explanation: Opening a valve changes the flow velocity and pressure with time, creating a transient rather than a steady flow.

• A. 0.5
• B. 1
• C. 2
• D. 0.66

Explanation: Laminar flow in a circular pipe has a parabolic profile, and integration of that profile gives an average velocity equal to half the…

• A. √(πx)
• B. x
• C. √(2x)
• D. √(x/2)

Explanation: The equivalent diameter is defined as 4A/P, where A is flow area and P is wetted perimeter. For a square, 4(x²)/(4x) gives x.

• A. Rate of velocity of liquid supply
• B. Rate of flow through delivery pipeline of a pump
• C. Intensity of pressure of the liquid
• D. Momentum rate through delivery pipe

Explanation: A hydraulic intensifier uses a large-area piston to produce a higher pressure on a smaller-area piston.

• A. Greater than the vapour pressure of the liquid
• B. Less than the vapour pressure of the liquid
• C. Equal to the vapour pressure of the liquid
• D. Less than barometric pressure

Explanation: The suction pressure head must remain above the liquid's vapour-pressure head so that vaporisation and cavitation do not occur at the pump…

• A. 0.3
• B. 0.9
• C. 0.03
• D. 0.66

Explanation: Maximum mean velocity occurs when the hydraulic radius is maximised for the circular open channel, giving approximately R/D = 0.30.

• A. 160
• B. 120
• C. 80
• D. 40

Explanation: For a fixed nominal pipe size, a higher schedule number indicates a thicker pipe wall.

• A. 0.5
• B. 1
• C. 1.5
• D. 2

Explanation: For the most economical rectangular open channel, the width is twice the depth, so b/y = 2.

• A. Specified mass flow rate cannot be achieved
• B. Valve is closed in the line
• C. Restriction in flow cross-section area occurs
• D. None of these

Explanation: Choking occurs when the flow reaches its limiting, usually sonic, condition and increasing the driving pressure cannot produce the…

• A. 4f2
• B. f1/4
• C. 2f1
• D. f1/2

Explanation: The Darcy or Darcy-Weisbach friction factor is four times the Fanning friction factor: f_D = 4f_F. Hence, f_F = f1/4.

• A. Viscous
• B. Laminar
• C. Turbulent
• D. Transition

Explanation: For internal pipe flow, Reynolds numbers below about 2100 are laminar and those above roughly 4000 are turbulent.

• A. Have different diameters
• B. Have the same diameter
• C. Are directly coupled
• D. None of these

Explanation: A hydraulic torque converter contains separate pump and turbine elements designed for different functions, so their runner or impeller…

• A. Is primarily a friction drag
• B. Occurs when NRe is very small
• C. Is independent of body length
• D. Depends mainly on cross-sectional shape

Explanation: Deformation drag is associated with viscous flow in which the fluid is deformed throughout a broad region around the body, characteristic…

• A. Velocity increases
• B. Both A. & B.
• C. Pressure decreases
• D. Neither A. nor B.

Explanation: For subsonic flow through a converging nozzle, continuity requires velocity to rise as area falls, and Bernoulli’s relation then gives a…

• A. Steep slope in flow
• B. Unsteady nature of flow
• C. Non-uniformity of flow
• D. Turbulence in flow

Explanation: Convective acceleration results from changes in velocity from one location to another, even when the flow is steady.

• A. Rotational
• B. Unsteady
• C. Turbulent
• D. Non-uniform

Explanation: Non-uniform flow means the velocity varies from one position to another at the same instant.

• A. f = 0.079.NRe-0.25
• B. f-0.5 = 4.07 loge (NRef)-0.6
• C. Both 'a' and 'b'
• D. None of these

Explanation: The Blasius correlation for the Fanning friction factor in smooth turbulent pipe flow is f = 0.079 Re⁻⁰·²⁵.

• A. Inertial and drag forces are important
• B. Drag force and gravitational forces are important
• C. Drag, gravitational and buoyancy forces are important
• D. None of the above

Explanation: At Reynolds number below 1, viscous drag balances the effective weight of the particle, which is the gravitational force reduced by…