What does the Reynolds number indicate in fluid mechanics?
a) The velocity of fluid flow
b) The type of flow (laminar or turbulent)
c) The viscosity of the fluid
d) The density of the fluid
For a low Reynolds number, the flow is typically:
a) Turbulent
b) Laminar
c) Transitional
d) None of the above
At what Reynolds number does the flow transition from laminar to turbulent?
a) 10
b) 1000
c) 2000
d) 5000
Which of the following factors affects the Reynolds number?
a) Fluid velocity
b) Fluid density
c) Fluid viscosity
d) All of the above
In a pipe, for Reynolds numbers greater than 4000, the flow is typically:
a) Laminar
b) Transitional
c) Turbulent
d) Steady
Which of the following is the unit for Reynolds number?
a) m/s
b) Dimensionless
c) Pa.s
d) kg/m³
The Reynolds number is defined as the ratio of:
a) Inertial forces to viscous forces
b) Viscous forces to inertial forces
c) Density to velocity
d) Temperature to density
For a given fluid, if the velocity increases, the Reynolds number:
a) Decreases
b) Remains constant
c) Increases
d) Becomes zero
What happens to the flow if the Reynolds number exceeds 4000?
a) The flow remains laminar
b) The flow becomes turbulent
c) The flow becomes unsteady
d) The flow remains steady
Which of the following indicates turbulent flow in a pipe?
a) Reynolds number less than 2000
b) Reynolds number greater than 4000
c) Reynolds number between 1000 and 2000
d) Reynolds number greater than 10000
The Reynolds number for flow through a pipe can be calculated using the formula:
a) Re = (density × velocity × diameter) / viscosity
b) Re = (velocity × viscosity) / density
c) Re = (diameter × velocity) / (density × viscosity)
d) Re = (density × viscosity) / (velocity × diameter)
What is the effect of increasing the fluid viscosity on the Reynolds number?
a) Increases the Reynolds number
b) Decreases the Reynolds number
c) No effect
d) Depends on the fluid velocity
Which of the following is a characteristic of laminar flow?
a) High Reynolds number
b) Smooth and orderly motion
c) Irregular fluctuations
d) High turbulence
In which of the following cases is the Reynolds number high?
a) Fluid flowing slowly in a small diameter pipe
b) Fluid flowing rapidly in a large diameter pipe
c) Fluid flowing slowly in a large diameter pipe
d) Fluid flowing rapidly in a small diameter pipe
At very high Reynolds numbers, fluid motion is typically:
a) Laminar
b) Turbulent
c) Steady
d) Uniform
Which of the following fluids would have a higher Reynolds number at the same flow rate?
a) Water
b) Honey
c) Oil
d) Glycerin
How does increasing the diameter of a pipe affect the Reynolds number?
a) Increases the Reynolds number
b) Decreases the Reynolds number
c) No effect
d) Depends on the pipe length
Which of the following flow conditions is most likely to occur in a low Reynolds number flow?
a) Viscous forces dominate
b) Inertial forces dominate
c) The flow becomes chaotic
d) The flow remains steady and non-uniform
For which of the following scenarios would you expect laminar flow?
a) Water flowing through a large, rough pipe at high speed
b) Airflow over an airplane wing at high speed
c) Honey flowing slowly through a small, smooth pipe
d) Water flowing rapidly through a large pipe
In turbulent flow, the flow is:
a) Smooth and steady
b) Chaotic with eddies and vortices
c) Laminar and ordered
d) Uniform throughout
What is the primary cause of transition from laminar to turbulent flow?
a) Increase in fluid velocity
b) Increase in pipe diameter
c) Decrease in fluid viscosity
d) Increase in temperature
The Reynolds number is most commonly used to determine the flow regime in:
a) Gases only
b) Liquids only
c) Both gases and liquids
d) None of the above
For flow through a pipe, the Reynolds number depends on all of the following except:
a) Fluid density
b) Pipe length
c) Fluid velocity
d) Pipe diameter
What happens to the Reynolds number when the fluid velocity is doubled, assuming constant density and viscosity?
a) It becomes four times larger
b) It remains unchanged
c) It doubles
d) It becomes half
Which of the following statements is true for turbulent flow?
a) The flow is predictable and smooth
b) The Reynolds number is less than 2000
c) The fluid moves in distinct layers
d) The flow exhibits random fluctuations
What is the effect of increasing the fluid density on the Reynolds number?
a) It increases the Reynolds number
b) It decreases the Reynolds number
c) It has no effect
d) It makes the flow laminar
The flow type in a pipe with a Reynolds number between 2000 and 4000 is generally considered:
a) Laminar
b) Turbulent
c) Transitional
d) Steady
