Top 550+ Solved Fluid Mechanics and Hydraulic Machines MCQ Questions Answer
Q. The flow in town water supply pipes is generally
a. Laminar
b. Turbulent
c. Transition
d. Any of the above.
Q. The most essential feature of a turbulent flow is
a. High velocity
b. Velocity at a point remains constant with time
c. Large discharge
d. Velocity and pressure at a point exhibit irregular fluctuations of high frequency.
Q. In turbulent flow the velocity distribution is a function of the distance y measured from the boundary surface and shear friction velocity uf, and follows a
a. Linear law
b. Hyperbolic law
c. Parabolic law
d. Logarithmic law.
Q. A turbulent flow is considered steady when
a. The algebraic sum of velocity fluctuations is zero
b. The velocity at a point does not change with Time
c. Temporal mean velocity at a point remains constant with time
d. The discharge remains constant.
Q. The Darcy-Weisbach friction factor f which is a direct measure of resistance to flow in pipes depends on which of the following?
a. Relative roughness, velocity and viscosity
b. Relative roughness, diameter and viscosity
c. Roughness height, diameter and velocity
d. Roughness height, diameter, velocity and kinematic viscosity.
Q. Commercial cast-iron and steel pipes carrying fluids under pressure are regarded as hydraulically smooth when
a. The laminar layer is thin as compared to the average height of roughness elements
b. The height of the roughness projections is low
c. The roughness elements are all completely covered by the laminar sublayer
d. None of the above.
Q. Intensity of turbulence is
a. The average K.E. of turbulence
b. The violence of turbulent fluctuations and is measured by the root mean square value of velocity fluctuations
c. The mean time interval between the reversals in the sign of velocity fluctuation
d. None of the above.
Q. Which of the following factors determine the friction factor for turbulent flow in a rough pipe?
a. Mach number and relative roughness
b. Froude’s number and Mach’s number
c. Reynolds number and relative roughness
d. Froude’s number and relative roughness.
Q. In case of turbulent flow of a fluid through a circular tube (as compared to the case of laminar flow at the same flow rate) the maximum velocity is ....., shear stress at the wall is ....., and the pressure drop across a given length is ....., the correct words for the blanks are, respectively
a. lower, higher, lower
b. lower, higher, higher
c. higher, lower, lower
d. higher, higher, higher
Q. In a laminar flow, Reynold’s number is
a. Less than 2000
b. More than 2000
c. More than 2000 but less than 4000
d. None of the above.
Q. In a turbulent flow, Reynold’s number is
a. Less than 4000
b. More than 4000
c. Between 2000 and 4000
d. None of the above.
Q. In case of a laminar flow, the loss of pressure head is
a. Proportional to (velocity)2
b. Proportional to velocity
c. Proportional to (velocity)1/2
d. None of the above.
Q. In case of a turbulent flow, the loss of head is approximately proportional to
a. Velocity
b. (Velocity) ^1/2
c. (Velocity) ^3/4
d. (Velocity) ^2
Q. Darcy-Weisbach equation is used to find loss of head due to :
a. Sudden enlargement
b. Sudden contraction
c. Friction
d. None of the above.
Q. The energy loss in a pipeline is due to
a. Surface roughness only
b. Viscous action only
c. Friction offered by pipe wall as well as by viscous function
d. None of the above.