What is the primary characteristic of turbulent flow?
A Uniform velocity
B Irregular motion
C Steady velocity
D Smooth layers
Turbulent flow is characterized by chaotic, irregular fluid motion with fluctuating velocities and eddies. This flow regime occurs at high Reynolds numbers and is common in high-speed fluid systems.
What does the continuity equation state about fluid flow in a pipe?
A Mass flow rate is constant
B Velocity varies
C Pressure is constant
D Temperature is constant
The continuity equation expresses the conservation of mass in a fluid system. It states that the mass flow rate of an incompressible fluid must remain constant throughout the flow, regardless of changes in pipe cross-sectional area.
Which factor significantly influences the drag force on an object moving through a fluid?
A Fluid density
B Fluid temperature
C Fluid velocity
D Object shape
The drag force on an object moving through a fluid is largely influenced by the shape of the object. Streamlined shapes create less drag by allowing smooth fluid flow, whereas blunt shapes cause higher drag due to turbulence.
What does Bernoulli’s principle relate in a fluid system?
A Velocity and mass
B Pressure and density
C Energy conservation
D Pressure and velocity
Bernoulli’s principle is based on the conservation of mechanical energy in a flowing fluid. It relates the pressure, velocity, and elevation in an incompressible fluid, stating that the total energy remains constant along a streamline.
In laminar flow, how does the velocity of the fluid change across the pipe cross-section?
A Increases at the center
B Decreases uniformly
C Constant across the section
D Increases uniformly
In laminar flow, the velocity is highest at the center of the pipe and decreases near the pipe walls due to friction. The flow forms a parabolic velocity profile with slower speeds near the boundary.
What does the Reynolds number predict?
A Temperature change
B Fluid density
C Type of flow
D Fluid pressure
The Reynolds number is a dimensionless quantity used to predict whether the fluid flow will be laminar or turbulent. A low Reynolds number indicates laminar flow, while a high Reynolds number suggests turbulent flow.
What is the main cause of cavitation in hydraulic systems?
A High velocity
B High viscosity
C Low pressure
D High temperature
Cavitation occurs when local pressure in a fluid drops below the vapor pressure, causing the formation of vapor bubbles. These bubbles collapse when they move to regions of higher pressure, causing damage to system components.
How does fluid viscosity affect flow resistance in pipes?
A No effect
B Increases resistance
C Depends on temperature
D Decreases resistance
Higher fluid viscosity results in greater internal friction, increasing resistance to flow. This higher resistance slows down the fluid and causes more energy loss in the system, especially in pipes with larger cross-sectional areas.
What is the purpose of a flow meter in a pipe system?
A Measure flow rate
B Measure temperature
C Measure pressure
D Measure velocity
A flow meter is used to measure the flow rate of a fluid in a pipe system. By determining how much fluid passes through a section of the pipe per unit time, it helps to control and monitor fluid transport.
What happens to the velocity of a fluid when it passes through a constriction in a pipe?
A Stays constant
B Depends on fluid
C Decreases
D Increases
According to the continuity equation, when the fluid flows through a constriction in the pipe, the velocity increases to maintain a constant flow rate. This happens because the cross-sectional area decreases as the fluid flows through.
How does temperature affect the viscosity of a fluid?
A Depends on fluid
B Decreases viscosity
C No effect
D Increases viscosity
For most fluids, an increase in temperature decreases viscosity. Higher temperatures cause the fluid molecules to move more freely, reducing internal friction and allowing the fluid to flow more easily.
What is the main difference between compressible and incompressible flow?
A Flow speed
B Pressure change
C Fluid density
D Flow rate
Compressible flow occurs when the fluid density changes significantly due to pressure or temperature changes, such as in gases. In incompressible flow, the fluid density remains constant, typically seen in liquids like water.
What does the drag force depend on in terms of the fluid properties?
A Density
B Pressure
C Temperature
D Viscosity
The drag force on an object moving through a fluid is influenced by the fluid’s density. Higher density fluids create more resistance against the object, leading to an increase in drag force.
What is the main effect of turbulent flow on pressure drop in a pipe?
A Fluctuates
B No effect
C Increases pressure
D Decreases pressure
Turbulent flow increases friction and energy losses due to chaotic fluid motion. This results in a higher pressure drop compared to laminar flow, where the flow is smooth and there is less resistance.
What is the function of a pump in a hydraulic system?
A Increase pressure
B Increase viscosity
C Decrease pressure
D Decrease velocity
A pump is used to increase the pressure of a fluid in a hydraulic system, enabling it to flow through pipes or channels to perform work, such as lifting or transporting the fluid over a distance.
