Questions
1. Viscosity is a function of
a) temperature
b) pressure
c) volume
d) stress
e) none of the above
2. According to Newton’s law of viscosity the plot of τxy versus – ( dvx / dy ) for a given fluid is
a) is a exponential curve
b) is a straight line through the origin and the slope of the line is the viscosity of the fluid
c) is a straight line not passing through the origin
d) is a constant line
e) none of the above
3. In the non-Newtonian fluids when η decreases with the increasing rate of shear the behavior is termed as
a) thixotropic
b) pseudoplastic
c) dilatant
d) Bingham plastic
e) none of the above
4. The fluids in which viscosity changes with time is called
a) pseudoplastic
b) binghamplastic
c) dilatent
d) thixotropic
e) none of the above
5. The equation of continuity in fluid mechanics
a) is condition of equilibrium in the flow pattern
b) is an embodiment of the law of thermodynamics
c) express the relation between work and energy
d) is an embodiment of the law of conservation of mass
e) none of the above
6. A cone-and-plate viscometer does not offer the following advantages
a. end effects are almost completely eliminated
b. magnitude of τθφ is very nearly constant throughout the field
c. only one stress component is required
d. all of the above
e. none of the above
7. Velocity distribution for laminar, incompressible laminar flow of a Newtonian fluid in a long circular tube is
a. linear
b. parabolic
c. zero
d. decreases exponentially
e. none of the above
8. The shell momentum balance is easy to apply when
a) the flow is laminar
b) the flow is rectilinear
c) the flow is curvilinear
d) the flow is viscous
e) none of the above
9. The Newton’s law of viscosity states that:
a) the stress is proportional to the velocity gradient
b) the stress is proportional to the negative of the local velocity gradient
c) the stress is inversely proportional to the pressure gradient
d) the stress is not related to the velocity component
e) none of the above
10. In laminar flow without rippling the Reynolds numbers lies in the range between
a) Re > 1000 to 2000
b) 4 to 25 < Re < 1000 to 2000
c) Re < 4 to 25
d) Re < 10
e) None of the above
11. In a flow through a circular tube the volume flow rate Q is defined as
a) the product of area and average velocity
b) area / velocity
c) area / (velocity)2
d) (area)2 / velocity
e) none of the above
12. In a laminar flow the Reynolds number (Re)
a) Re > 2000
b) Re > 2500
c) Re < 2100
d) Re = 1500
e) None of the above
13. The equation of continuity describes
a) rate of change of mass at a fixed point
b) rate of change of density at a fixed point resulting from the changes in the mass velocity vector
c) rate of change of area at a fixed point
d) rate of change of volume at a fixed point
e) none of the above
14. The momentum flows into and out of the volume element by two mechanisms
a) convection and conduction
b) convection and molecular transfer
c) conduction and radiation
d) molecular transfer and radiation
e) none of the above
15. In the Euler equation
a) ▼ ▪ τ ≠ 0
b) ▼ ▪ τ ≥ 0
c) ▼ ▪ τ ≤ 0
d) ▼ ▪ τ = 0
e) None of the above
16. In the Navier-stokes equation,
a) ρ and μ are constant
b) ρ and μ are changing
c) ρ is constant and μ is changing
d) ρ is changing and μ is constant
e) none of the above
17. For studying flow through porous media, the following equation is used
- Navier-Stokes flow
- Euler equation
- Hagen-Poiseuille equation
- Stokes flow
- None of the above
18. Turbulent flow is observed when
- film velocity increases, thickness of film decreases, kinematic viscosity decreases
- film velocity increases, thickness of film decreases, kinematic viscosity increases
- film velocity increases, thickness of film increases, kinematic viscosity decreases
- film velocity decreases, thickness of film increases, kinematic viscosity decreases
- none of the above
19. The following is not an assumption of the Hagen-Poiseuille equation
- density is constant
- flow is independent of time
- flow is turbulent
- fluid is Newtonian
- fluid behaves as a continuum
20. A fluid which is both incompressible and frictionless is called
- turbulent fluid
- ideal fluid
- laminar fluid
- Eulerian fluid
- viscous fluid