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Fluid Mechanics Fundamentals
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Fluid Mechanics Fundamentals
Fluid Mechanics Fundamentals
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1
Question
What are the primary physical properties characterizing a practical fluid?
Answer
Practical fluids possess the properties of viscosity, surface tension, and compressibility.
2
Question
How do liquids behave in terms of shape and volume when placed in a container?
Answer
Liquids take the shape of their container but maintain a fixed volume.
3
Question
How does the specific weight of a liquid change when measured on different planets?
Answer
The specific weight changes depending on the local gravity of the planet.
4
Question
What is the standard specific weight of water expressed in SI units?
Answer
The specific weight of water is 9.81 kN/m³ or 9810 N/m³.
5
Question
Why is the specific weight of sea water typically higher than that of pure water?
Answer
Dissolved salts and minerals make sea water denser and heavier than pure water.
6
Question
To which category of fluids does water belong according to its flow behavior?
Answer
Water is considered a Newtonian fluid.
7
Question
What property allows fluids to change their volume when subjected to external pressure?
Answer
Compressibility allows a fluid to change its volume under pressure.
8
Question
What is the term for the attractive force between molecules of the same fluid?
Answer
Cohesion is the attraction between the same type of molecules.
9
Question
Which fluid property causes falling drops of water to assume a spherical shape?
Answer
Surface tension pulls the water into a sphere to minimize its surface area.
10
Question
What is the shape of the free surface of mercury in an open glass tube?
Answer
Mercury curves downward, creating a convex meniscus shape.
11
Question
What happens to the liquid level in a glass tube if cohesion is stronger than adhesion?
Answer
The liquid level inside the tube will drop below the level of the outside liquid.
12
Question
What specific type of pressure is measured using a barometer?
Answer
A barometer is used to measure atmospheric pressure.
13
Question
In what scenario is a piezometer typically used for pressure measurement?
Answer
Piezometers measure low or moderate pressures in liquid systems.
14
Question
Where are manometers commonly applied in fluid engineering?
Answer
Manometers measure pressure in pipes, closed tanks, and water channels.
15
Question
What is the primary function of a differential manometer?
Answer
It measures the difference in pressure between two distinct points.
16
Question
What terms describe pressure that is lower than the local atmospheric pressure?
Answer
This is called vacuum pressure or negative gauge pressure.
17
Question
What is the mathematical relationship between absolute pressure and gauge pressure?
Answer
Gauge pressure equals absolute pressure minus the local atmospheric pressure.
18
Question
Which environmental factors cause atmospheric pressure to vary?
Answer
Atmospheric pressure changes with altitude, temperature, and humidity.
19
Question
What are the two main reasons mercury is used as the working fluid in barometers?
Answer
Mercury is used because it is very dense and has low vapor pressure.
20
Question
Under what geometric condition is the total pressure force on a plane equal to the area times the pressure at its centroid?
Answer
This applies to any flat surface in a static liquid regardless of its angle.
21
Question
How is the position of the centre of pressure related to the centroid of a vertical immersed plane?
Answer
The centre of pressure is always located below the centroid of the plane.
22
Question
According to Archimedes' Principle, what is the magnitude of the buoyant force on an immersed body?
Answer
The buoyant force equals the weight of the fluid the object displaces.
23
Question
What is the requirement for a floating body to be in stable equilibrium?
Answer
A floating body is stable if the metacentre is higher than the center of gravity.
24
Question
How is the centre of buoyancy defined for a partially or fully submerged object?
Answer
It is the center of the volume of the liquid pushed aside by the object.
25
Question
How does the water level in a tank change when the truck carrying it undergoes constant horizontal acceleration?
Answer
Water level goes up at the back and down at the front of the tank.
26
Question
How should wagons for carrying liquids be designed for transport through steep mountainous regions?
Answer
The wagons should be designed so the bottom stays level with the ground.
27
Question
In a revolving cylinder, how does the rise of liquid at the walls compare to the depression at the axis?
Answer
The liquid rises at the edges exactly as much as it drops in the center.
28
Question
How does pressure vary radially when a liquid rotates at a constant angular velocity about a vertical axis?
Answer
Pressure increases with the square of the distance from the center of rotation.
29
Question
What condition must be met for a fluid flow to be classified as 'steady flow'?
Answer
Steady flow means the fluid conditions at a point do not change over time.
30
Question
Under what circumstances is fluid flow defined as 'uniform flow'?
Answer
Uniform flow means velocity and flow area stay the same along the path.