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WorksheetsIntroduction to Fluid Dynamics
Total questions: 24
Worksheet time: 44mins
Define Gas Dynamics.
Motion of incompressible fluids
Flow of gases (especially air) over bodies at high or low speeds
Motion of compressible fluids
Fluids flow that going on significant density changes
The following statements define characteristics of a fluid except ......
Strongest inter-molecular bonds
Molecules move about at random
Molecules move about each other, but the volume remains constant due to strong cohesive forces between molecules
Expands until it encounters the wall of the container and fills the entire space available
which one of the following statements does not define the fluid characteristics when shear force is applied?
Never stops deforming and approaches a constant rate of strain.
Deforms continuously under the influence of shear stress.
Stress is proportional to strain rate.
Tangential stress is proportional to viscosity
Define no slip condition.
A fluid in rest increase at the surface and assumes a maximum velocity relative to the surface.
A fluid in rest comes to a complete stop at the surface and assumes a zero velocity relative to the surface.
A fluid in motion comes to a complete stop at the surface and assumes a zero velocity relative to the surface.
A fluid in motion increase at the surface and assumes a maximum velocity relative to the surface.
Define a boundary layer.
When a fluid is forced to flow over a curved surface, the boundary layer may no longer remain attached to the surface, and separates from the surface
All velocity profiles must have zero values with respect to the surface at the points of contact between a fluid and a solid surface
The force a fluid exerts on a surface in the flow direction
The flow region adjacent to the wall in which the viscous effects (thus, the velocity gradients) are significant
All the statements below describe viscosity correctly except .....
Flows where the frictional effects are significant is called inviscid flow regions
When 2 fluid layers move relative to each other, a friction force develops between them and the slower layer tries to slow down the faster layer
Cause by cohesive forces between the molecules in liquids and by molecular collisions in gases
No fluid with zero viscosity
Which statement below is the best to describe a laminar flow?
A flow that alternates between laminar and turbulent
The flow of high-viscosity fluids (e.g. oil) at low velocities
The highly ordered fluid motion characterized by smooth layers of fluid
The highly disordered fluid motion that typically occurs at high velocities and is characterized by velocity fluctuations
Define turbulent flow.
The highly disordered fluid motion that typically occurs at high velocities and is characterized by velocity fluctuations
The flow of high-viscosity fluids (e.g. oil) at low velocities
The highly ordered fluid motion that typically occurs at high velocities and is characterized by velocity fluctuations
The highly ordered fluid motion characterized by smooth layers of fluid
Select the correct answer.
Key parameter to determine the flow regime is by Reynolds number
Reynolds number for turbulent flow is smaller than 4000
Reynolds number for laminar flow is larger than 2300
Reynolds number for transition flow is 2300>Re>4000
Natural flow is ...
a fluid motion in an enclosure
a fluid that is forced to flow over a surface or in a pipe by external means such as pump or fan.
is due to natural means such as the buoyancy effect, which manifests itself as the rise of warmer (and lighter) fluid and the fall of cooler (and denser) fluid.
is due to natural means such as the buoyancy effect, which manifests itself as the rise of cooler (and denser) fluid and the fall of warmer (and lighter) fluid.
Which statement is wrong?
The force a flowing fluid exerts on a body in the flow direction is called the tangential component of force
A property that represents the internal resistance of a fluid to motion is viscosity
The force a flowing fluid exerts on a body in the flow direction is called the drag force
For liquids, both the dynamic and kinematic viscosities are practically independent of pressure
Choose the correct answer.
Turbulent flow = The highly ordered fluid motion characterized by smooth layers of fluid.
Transitional flow =
A flow that alternates between laminar and turbulent
Laminar flow =
highly disordered fluid motion that typically occurs at high velocities and is characterized by velocity fluctuations.
Laminar flow = The flow of low-viscosity fluids (e.g. air) at high velocities
Reynolds number for turbulent flow must larger than...?
(a)
One litre of water occupies a volume of
100 cm3
250 cm3
500 cm3
1000 cm3
Which of the followings is NOT TRUE about liquid:
take the shape of the container
possess free surface
volume is constant compared to gas
strong cohesive bonds compared to bonds in gas and solid
The study of force which produces motion in a fluid is called as
fluid statics
fluid dynamics
fluid kinematics
none of the above
What do we call the the amount of force exerted on a certain area?
fluid
pressure
buoyant force
normal force
carbon nanotube
Which of the following is a fluid?
helium
copper
iron
gold
Any substance that can easily flows and therefore can easily change shape.
Fluid
Liquid
Gas
Solid
An ideal fluid is .....
A real fluid with zero viscosity
A perfect fluid that exists in this world
A theoretical frictionless fluid
a fluid with a nonzero normal velocity at the surface
