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This set of Fluid Mechanics and Machinery Multiple Choice Questions & Answers (MCQs) focuses on Fluid Mechanics And Machinery Set 9
Q1 | Hydraulic gradient line takes into consideration
- potential and kinetic heads only
- potential and pressure heads only
- kinetic and pressure heads only
- potential, kinetic and pressure heads
Q2 | Which of the following is true?
- egl always drops in the direction of c
- egl always rises in the direction of flow
- egl always remains constant in the direction of flow
- egl may or may not in the direction of flow
Q3 | Which of the following is true?
- hgl always drops in the direction of flow
- hgl always rises in the direction of flow
- hgl always remains constant in the direction of flow
- hgl may or may not in the direction of flow
Q4 | Which of the following is true?
- hgl will never be above egl
- hgl will never be under egl
- hgl will never coincide with egl
- hgl will may or may not be above egl
Q5 | The vertical intercept between EGL and HGL is equal to
- pressure head
- potential head
- kinetic head
- piezometric head
Q6 | The slope of HGL will be
- greater than that of egl for a pipe of uniform cross-section
- smaller than that of egl for a pipe of uniform cross-section
- equal than that of egl for a pipe of uniform cross-section
- independent of that of egl for a pipe of uniform cross-section
Q7 | For a nozzle, the vertical intercept between EGL and HGL
- increases
- decreases
- remains constant
- may increase or decrease
Q8 | For a diffuser, the vertical intercept between EGL and HGL
- increases
- decreases
- remains constant
- may increase or decrease
Q9 | Which of the following is true?
- the slope of egl will always be greater than that of the axis of the pipe
- the slope of egl will always be smaller than that of the axis of the pipe
- the slope of egl will always be equal to that of the axis of the pipe
- the slope of egl will always be independent of that of the axis of the pipe
Q10 | For a fully-developed pipe flow, how does the pressure vary with the length of the pipe?
- linearly
- parabolic
- exponential
- constant
Q11 | When a problem states “The velocity of the water flow in a pipe is 20 m/s”, which of the following velocities is it talking about?
- rms velocity
- average velocity
- absolute velocity
- relative velocity
Q12 | Which of the factors primarily decide whether the flow in a circular pipe is laminar or turbulent?
- the prandtl number
- the pressure gradient along the length of the pipe
- the dynamic viscosity coefficient
- the reynolds number
Q13 | How is Reynolds number defined as?
- ratio of pressures in the inlet to the outlet of a pipe
- the product of velocity of the flow and the diameter of the pipe, divided by the kinematic viscosity of fluid
- the product of density of the fluid, velocity of the flow and the diameter of the pipe, divided by the dynamic viscosity of fluid
- ratio of inertia force to viscous force
Q14 | A circular pipe of radius 7 cm is used for water flow transmission. This pipe is moulded into another pipe with a square cross-section keeping the length same. (Ignore the thickness of the pipe). Calculate the hydraulic diameter of the moulded pipe. (Take π = 22/7).
- 11 cm
- 7 cm
- 3.5 cm
- 22 cm
Q15 | The Reynolds number is found out for a flow in a circular pipe. This circular pipe is moulded into a square pipe, keeping length of the pipe same. Ignore the thickness of the pipe. The Reynolds number changes by
- 57% decrease
- 57% increase
- 43% decrease
- 43% increase
Q16 | The flow through a circular pipe is laminar. Now, the fluid through the pipe is replaced with a more viscous fluid and passed through the pipe again with the same velocity. What can we say about the nature of this flow?
- the flow will become turbulent
- the flow will be a transition flow
- the flow will remain laminar
- the reynolds number of the earlier flow is required to answer this question
Q17 | What can be the maximum diameter of the pipe for the water flow of velocity 1 m/s (ν = 10-6) to be laminar in nature? Assume Lower critical Reynolds number to be 2100.
- 2.1 mm
- 21 mm
- 21 cm
- 0.21 mm
Q18 | Which of the following flows have the highest critical Reynolds number (lower)?
- flow in a pipe
- flow between parallel plates
- flow in an open channel
- flow around spherical body
Q19 | The flow separation occurs when the fluid travels away from the
- surface
- fluid body
- adverse pressure gradient
- inter-molecular spaces
Q20 | The swirl caused due to eddies are called as
- vortices
- vertices
- volume
- velocity
Q21 | Eddy viscosity is a turbulent transfer of
- fluid
- heat
- momentum
- pressure
Q22 | Which among the following is a device that converts a laminar flow into a turbulent flow?
- dead weight gauge
- vacuum gauge
- turbulator
- ionization gauge
Q23 | Boundary layer separation does not undergo detachment.
- true
- false
Q24 | With the boundary layer separation, displacement thickness
- increases
- decreases
- remains same
- independent
Q25 | What is the instrument used for the automatic control scheme during the fluid flow?
- rotameters
- pulley plates
- rotary piston
- pilot static tube