Embedded Files
General & Based on Syllabus
How would you explain fluid mechanics to a non-engineering person?
Fluid mechanics is the study of how liquids and gases behave when they are at rest or in motion. In simple terms, it explains everyday things like: how water flows from a tap, how air moves around a moving car or airplane, how oil lubricates machines.
2. Name of different Units or Chapters?
Unit 1: Introduction to Fluid Mechanics
Study of properties and behavior of fluids (liquids and gases) at rest and in motion.
Unit 2: Fluid Statics
Study of fluids at rest and the pressure forces acting on them.
Unit 3: Fluid Kinematics
Study of fluid motion without considering the forces causing it.
Unit 4: Fluid Dynamics
Study of fluid motion along with the forces and energy causing the flow.
Unit 5: Internal flow
Study of fluid flow inside closed conduits like pipes and ducts.
Unit 6: External flow and Dimensional Analysis
Study of fluid flow over surfaces and use of dimensionless analysis to simplify problems.
Exp.1: Determination of fluid viscosity and its variation with temperature.
1. What is viscosity?
Viscosity is the property of a fluid that resists relative motion between its layers (internal resistance to flow).
2. Define dynamic viscosity and kinematic viscosity.
Dynamic viscosity (μ): Resistance offered by fluid to shear.
Kinematic viscosity (ν): Ratio of dynamic viscosity to density
3. What are the SI units of viscosity?
Dynamic viscosity: Pa·s (N·s/m²)
Kinematic viscosity: m²/s
4. State Newton’s law of viscosity.
Shear stress is directly proportional to velocity gradient:
5. What is meant by a Newtonian and non-Newtonian fluid? Give examples.
Newtonian: Obey Newton’s law (e.g., water, air)
Non-Newtonian: Do not obey (e.g., toothpaste, paint)
6. What is the physical significance of viscosity?
It indicates how easily a fluid flows; higher viscosity → more resistance (thicker fluid).
7. Write the expression for viscosity used in this experiment.
ν= 0.0026t – 1.175/t
8. What is the effect of temperature on viscosity of: liquids, gases
Liquids: Viscosity decreases with temperature
Gases: Viscosity increases with temperature
9. Why does viscosity of liquids decrease with temperature?
With rise in temperature, intermolecular forces weaken, so fluid flows more easily.
10. Explain the working principle of the viscometer used.
Redwood viscometer is used in this experiment, it works on the principle that time required for a fixed volume of liquid to flow through an orifice is related to its viscosity. Higher the viscosity, more will be the time taken.
11. Why do we take multiple readings?
To reduce experimental error and obtain an accurate average value.
12. What are the sources of error in this experiment?
Temperature fluctuations, Parallax error in readings, Air bubbles, Improper calibration
13. What graph is plotted in this experiment?
Viscosity vs Temperature graph (generally decreasing curve for liquids).
14. What conclusion do you draw from the experiment?
Viscosity of liquid decreases with increase in temperature, confirming theoretical behavior.
15. Give real-life applications where viscosity is important.
Lubrication in engines, Oil flow in pipelines, Blood flow in human body, Paint and coating processes
Exp.2: Determination of pressure using manometers
What is pressure?
Pressure is the force acting per unit area (P=F/A).
2. State Pascal’s Law.
Pressure applied to a confined fluid is transmitted equally in all directions.
3. State Hydrostatic Law
Pressure in a fluid at rest increases linearly with depth (P=ρgh).
4. Define gauge pressure and absolute pressure.
Gauge pressure is measured relative to atmospheric pressure, while absolute pressure is measured from absolute vacuum.
5. Write the relation between absolute, gauge, and atmospheric pressure.
Absolute pressure = Atmospheric pressure + Gauge pressure.
6. What is a manometer?
A device used to measure pressure using liquid columns.
7. Why are manometers used instead of pressure gauges?
They are simple, accurate, and do not require calibration.
8. What are the types of manometers?
Simple (U-tube, single column) and Differential manometers.
9. What is the difference between simple and differential manometer?
Simple measures pressure at one point; differential measures pressure difference between two points.
10. Explain the working of a U-tube manometer.
Pressure difference causes liquid to rise in one limb and fall in the other, giving height difference.
11. What is an inverted U-tube manometer and where is it used?
Uses lighter fluid and is used for measuring small pressure differences in liquids.
12. Write the basic pressure equation used in manometers.
P = ρ g h
13. Why is mercury commonly used as manometric fluid?
High density, low vapor pressure, and clear visibility.
14. What is specific gravity and its role in manometer calculations?
Ratio of density of fluid to water; used to relate densities in calculations.
15. What readings are taken during the experiment?
Height difference of liquid columns in the manometer.
16. What precautions should be taken while using a manometer?
Avoid air bubbles, ensure vertical alignment, and take accurate readings.
17. What are the limitations of a manometer?
Bulky, slow response, not suitable for very high pressures.
18. Where are manometers used in real-life applications?
Used in laboratories, pipelines, HVAC systems, and fluid flow measurements.
Exp.3: Determination of Metacentric height of floating object.
1. What is buoyancy?
Buoyancy is the upward force exerted by a fluid on a body when it is partially or fully immersed in it.
2. State Archimedes’ Principle.
It states that a body immersed in a fluid experiences an upward force equal to the weight of the fluid displaced by it.
3. What is the center of buoyancy?
It is the point through which the buoyant force acts, and it lies at the centroid of the displaced fluid.
4. What is the center of gravity?
It is the point where the entire weight of the body acts vertically downward.
5. Define metacenter.
When a floating body is slightly tilted, the new line of buoyant force intersects the original vertical line at a point called metacenter.
6. What is metacentric height (GM)?
It is the distance between the center of gravity and the metacenter, and it determines the stability of the body.
7. What do you mean by stable, unstable, and neutral equilibrium of a floating body?
If the body returns to original position → stable, moves further away → unstable, stays in new position → neutral.
8. What is the condition for stable equilibrium?
A floating body is stable when metacentric height (GM) is positive.
9. What happens if metacentric height is negative?
If GM is negative, the body becomes unstable and may topple.
10. Why is metacentric height important for floating bodies?
Metacentric height is important because it tells whether a floating body like a ship is stable or not.
11. Write the formula for metacentric height.
Metacentric height is given by the formula: GM= (w×d) / ((W+w)×tanθ)
It can also be expressed as GM=BM−BG.
12. What do each term in this formula represent?
Here, w is the moving weight, d is the distance moved, W is total weight of the body, and θ is the angle of tilt.
GM represents metacentric height, which indicates stability.
13. Describe the apparatus used in this experiment.
The setup consists of a floating body placed in a water tank, a movable weight on a graduated scale, and a pointer to measure tilt. It is used to study stability by shifting the weight.
14. Why is a movable weight used?
A movable weight is used to shift the center of gravity of the body. This helps in creating a tilt so that metacentric height can be calculated.
15. What observations are recorded?
We record the distance through which the weight is moved and the corresponding angle of tilt of the body.
These readings are used to calculate GM.
16. How do you measure the angle of tilt?
The angle of tilt is measured using a pointer attached to the body and a graduated scale. Sometimes, it is calculated using displacement readings.
17. Why does the body tilt when weight is shifted?
When the weight is shifted, the center of gravity of the body moves. This creates an unbalanced moment, causing the body to tilt.
18. How does shifting weight affect stability?
Shifting weight away from the center increases the tilt and may reduce stability. If shifted too much, it can make the body unstable.
19. What are the sources of error in this experiment?
Errors may occur due to incorrect angle measurement, improper leveling, or wave disturbances in water. Inaccurate weight shifting can also affect results.
Exp.4: Determination of Reynolds number and flow visualization of laminar and turbulent flow using Reynolds apparatus.
1. What is Reynolds number?
Reynolds number is a dimensionless number that indicates the nature of fluid flow. It is the ratio of inertial forces to viscous forces in a fluid.
2. What does Reynolds number represent physically?
It represents whether the flow is smooth or disturbed. Lower values indicate laminar flow, while higher values indicate turbulent flow.
3. Define laminar, turbulent and transition flow?
Laminar flow is smooth and orderly, turbulent flow is irregular and chaotic, and transition flow lies between the two.
4. Write the formula for Reynolds number.
Reynolds number is given by Re = ρVD / μ.
5. What do each term in this formula represent?
ρ is fluid density, V is velocity, D is pipe diameter, and μ is dynamic viscosity.
6. What are the critical Reynolds number values for pipe flow?
For pipe flow, Re < 2000 indicates laminar flow, Re between 2000–4000 is transition, and Re > 4000 is turbulent flow.
7. Why is Reynolds number dimensionless?
Because it is a ratio of two forces, so all units cancel out. Hence, it has no units.
8. What is Reynolds apparatus?
It is an experimental setup used to study flow patterns and determine Reynolds number. It includes a pipe, dye injector, and flow control system.
9. Describe the working principle of Reynolds experiment.
Fluid flows through a transparent pipe, and dye is injected into it. The flow pattern of the dye indicates whether the flow is laminar or turbulent.
10. Why is dye injected in the experiment?
Dye is injected to visualize the flow pattern clearly. It helps distinguish between laminar and turbulent flow.
11. What type of dye is used and why?
A colored, non-reactive dye is used so it does not mix immediately and remains visible.
12. How do you identify laminar flow in the experiment?
In laminar flow, the dye moves in a straight, smooth line without mixing.
13. How do you identify turbulent flow?
In turbulent flow, the dye spreads out and mixes randomly with the fluid.
14. What happens to dye filament at transition stage?
The dye line becomes wavy and unstable. It starts to break and mix partially.
15. What observations are taken during the experiment?
We record time to calculate flow rate, and observe dye behavior in the pipe.
16. What precautions are necessary?
Maintain steady flow, avoid vibrations, and ensure smooth dye injection.
17. What are possible sources of error?
Errors can occur due to unsteady flow, improper dye injection, or inaccurate measurements.
18. What are practical applications of Reynolds number?
It is used in pipe design, fluid transport systems, and predicting flow behavior in engineering applications.
Exp.5: Draw flow net using electrical analogy apparatus.
What is a flow net?
A flow net is a graphical representation of fluid flow consisting of streamlines and equipotential lines.
It helps in visualizing flow patterns in a fluid.
2. What are streamlines and equipotential lines?
The line drawn in the flow field such that tangent drawn at each point will give direction of velocity at that point is known as Streamline. It show the direction of fluid flow at every point. Equipotential lines are the lines for which value of velocity potential function is constant.
3. What is the main purpose of a flow net?
The main purpose is to analyze flow behavior and calculate parameters like seepage and pressure distribution.
4. What are the characteristics of a flow net?
Streamlines and equipotential lines intersect at right angles and form approximate squares. They are smooth curves and never cross each other.
5. What is electrical analogy in fluid flow?
Electrical analogy is a method where electrical current flow is used to represent fluid flow behavior.
6. Which quantities are analogous between electrical flow and fluid flow?
Voltage corresponds to hydraulic head and it is used to draw equipotential lines, and electric current corresponds to fluid discharge and it is used to draw streamlines.
7. How do you obtain equipotential lines in the experiment?
Equipotential lines are obtained by measuring points having the same voltage using a probe.
8. How are streamlines drawn from equipotential lines?
Streamlines are drawn perpendicular to the equipotential lines at every point.
9. What observations are recorded?
We record voltage readings at different points and plot equipotential lines accordingly.
10. What precautions should be taken?
Ensure proper electrical connections, avoid loose contacts, and take accurate voltage readings.
11. What are the limitations of electrical analogy?
It gives approximate results and may not represent complex real fluid behavior accurately.
12. Where are flow nets used in real-life applications?
Flow nets are used in seepage analysis under dams, canals, and groundwater flow studies.
Exp.6: Verification of modified Bernoulli’s equation.
1. What is Bernoulli’s theorem?
Bernoulli’s theorem states that the total energy of a flowing fluid remains constant along a streamline.
It includes pressure, velocity, and elevation energy.
2. Write Bernoulli’s equation.
P/ρg + V2/2g + z = Constant
3. What are the assumptions of Bernoulli’s theorem?
The flow is steady, incompressible, and frictionless. Also, the fluid flows along a streamline.
4. What are different forms of energy in flowing fluid?
Pressure energy, kinetic energy (velocity head), and potential energy (elevation head).
5. What is modified Bernoulli’s equation?
It is the practical form of Bernoulli’s equation that includes energy losses in the system.
6. Why is Bernoulli’s equation modified?
Because real fluids experience friction and energy losses, which are not considered in the basic equation.
7. What are head losses in fluid flow?
Head losses are the loss of energy due to friction and turbulence in the flow.
8. What is hydraulic grade line (HGL)?
HGL represents the sum of pressure head and elevation head along the flow.
9. What is total energy line (TEL)?
TEL represents the total energy, i.e., pressure head + velocity head + elevation head.
10. Write the modified Bernoulli’s equation.
P1/ρg + V12/2g + z1 = P2/ρg + V22/2g + z2 + hf
11. What does each term in the equation represent?
P/ρg is pressure head,
V2/2g is velocity head,
z is elevation head,
and hf represents head loss due to friction.
12. What is head loss (hf)?
Head loss is the loss of mechanical energy due to friction and resistance in the flow.
13. How do velocity head and pressure head differ?
Velocity head represents kinetic energy of fluid motion, while pressure head represents pressure energy of the fluid.
14. What readings are taken during the experiment?
Pressure at different points, flow rate, and sometimes elevation difference are recorded.
15. How is discharge measured?
Discharge is measured by collecting fluid in a tank and noting volume per unit time.
16. Why does energy decrease along the flow?
Energy decreases due to frictional resistance and turbulence in the pipe.
17. What are sources of losses in pipe flow?
Losses occur due to pipe friction, bends, valves, and sudden changes in area.
18. What precautions are taken during the experiment?
Ensure steady flow, avoid air bubbles, and take accurate readings of pressure and discharge.
Exp.7: Determination of Coefficient of Discharge of Orifice Meter
1. What is an orifice meter?
An orifice meter is a device used to measure the flow rate of fluid in a pipe by creating a pressure difference.
2. Why is an orifice meter used?
It is used to measure discharge in pipelines because it is simple, compact, and economical.
3. What is discharge?
Discharge is the volume of fluid flowing per unit time through a pipe.
4. What is coefficient of discharge (Cd)?
It is the ratio of actual discharge to theoretical discharge. It accounts for losses in the system.
5. Why is Cd less than 1?
Because of energy losses due to friction, turbulence, and contraction of flow.
6. Write the expression for theoretical discharge
7. Write the expression for coefficient of discharge:
Cd= Qact/Qth
8. What is actual discharge and how is it measured?
Actual discharge is the real flow rate measured experimentally. It is measured by collecting water in a tank and noting volume per time.
9. What is the role of differential manometer in this experiment?
It measures the pressure difference across the orifice, which is used to calculate discharge.
10. What are the parts of an orifice meter?
It consists of an orifice plate, pipe section, pressure tapping points, and a differential manometer.
11. What is vena contracta?
It is the point just downstream of the orifice where the jet area is minimum and velocity is maximum.
12. What is coefficient of velocity and coefficient of contraction?
Coefficient of velocity is the ratio of actual to theoretical velocity. Coefficient of contraction is the ratio of jet area at vena contracta to orifice area.
13. What observations are recorded?
Pressure difference, discharge, and time taken to collect fluid are recorded.
14. What precautions should be taken?
Ensure no leakage, steady flow, and accurate manometer readings.
15. Why does pressure drop across the orifice?
Because velocity increases as fluid passes through the small opening, causing pressure to decrease.
16. What are sources of error in this experiment?
Errors may occur due to leakage, inaccurate readings, or unsteady flow conditions.
17. What are applications of orifice meter?
It is used in industries to measure flow in pipelines like water supply, oil, and gas systems.
Exp.8: Determination of Coefficient of Discharge of Venturi Meter
1. What is a Venturimeter?
A Venturimeter is a device used to measure the flow rate (discharge) of a fluid in a pipe. It works on Bernoulli’s principle by measuring the pressure difference between the inlet and the throat.
2. What is discharge? What is coefficient of discharge (Cd)?
Discharge is the volume of fluid flowing per unit time through a pipe. Coefficient of discharge (Cd) is the ratio of actual discharge to theoretical discharge.
3. Why is Cd close to 1 for a Venturimeter?
Because the Venturimeter has smooth flow passage with gradual changes, resulting in very small energy losses.
4. Write the expression for theoretical discharge through Venturimeter.
5. Write the expression for coefficient of discharge:
Cd= Qact/Qth
6. What is the role of differential manometer?
It measures the pressure difference between the inlet and throat of the Venturimeter.
7. How is actual discharge measured?
Actual discharge is measured by collecting fluid in a tank and noting volume per unit time.
8. What are the parts of a Venturimeter?
It consists of a converging section, throat, diverging section, pressure taps, and a manometer.
9. What is the function of converging section?
It gradually reduces the area and increases the velocity of fluid.
10. What is the function of throat?
It has minimum area where velocity is maximum and pressure is minimum.
11. What is the function of diverging section?
It gradually increases the area and helps in pressure recovery.
12. Describe the working principle of Venturimeter.
It works on Bernoulli’s principle, where an increase in velocity at the throat causes a decrease in pressure, which is used to measure discharge.
13. What observations are recorded during the experiment?
Pressure difference, time, and volume of collected fluid are recorded.
14. What precautions should be taken?
Ensure steady flow, avoid air bubbles, and take accurate readings.
15. Why does pressure decrease at the throat?
Because velocity increases at the throat, and according to Bernoulli’s principle, pressure decreases.
16. What are sources of error in this experiment?
Errors may occur due to leakage, improper readings, or unsteady flow.
17. What are applications of Venturimeter?
It is used in water supply systems, pipelines, and industries for accurate flow measurement.
Exp.9: Determination of major losses through pipes.
1. What are major losses in pipe flow?
Major losses are the energy losses that occur due to friction between the fluid and the pipe along its length.
2. What is frictional loss?
Frictional loss is the loss of energy due to friction between moving fluid and pipe walls.
3. What is the difference between major and minor losses?
Major losses occur due to pipe length, while minor losses occur due to fittings like bends, valves, and expansions.
4. What factors affect major losses?
They depend on pipe length, diameter, flow velocity, fluid properties, and pipe roughness.
5. Write the Darcy–Weisbach equation for head loss.
hf = 4flv2 / 2dg
6. What do each terms in this equation represent?
hf is head loss, f is coefficient of friction, L is pipe length, D is diameter, and V is velocity of flow.
7. How does Reynolds number affect friction factor?
For laminar flow, friction factor decreases with increase in Reynolds number, while for turbulent flow it depends on both Reynolds number and pipe roughness.
8. Describe the apparatus used in this experiment.
The setup consists of a long pipe, pressure tapping points, a differential manometer, and a flow measuring tank.
9. What readings are taken during the experiment?
Pressure difference between two points, discharge, and time are recorded.
10. How is head loss measured?
Head loss is calculated from the pressure difference measured using a manometer.
11. Why is pressure difference measured between two points?
Because head loss is directly related to the drop in pressure along the pipe.
12. Why does head loss occur in pipes?
It occurs due to friction and turbulence as fluid flows through the pipe.
13. How does pipe roughness affect losses?
Greater roughness increases friction and hence increases head loss.
14. What happens to losses if velocity increases?
Head loss increases significantly as it is proportional to the square of velocity.
15. What are sources of error in this experiment?
Errors may occur due to leakage, inaccurate readings, or unsteady flow.
16. Where is this concept used in real life?
It is used in designing pipelines, water supply systems, and oil and gas transport systems.
17. How can major losses be reduced in pipelines?
They can be reduced by using smooth pipes, proper diameter, and maintaining lower flow velocity.
Exp.10: Determination of minor losses through pipes.
1. What are minor losses in pipe flow?
Minor losses are energy losses that occur due to pipe fittings like bends, valves, expansions, and contractions.
2. Why are they called “minor” losses?
They are called minor because their magnitude is usually smaller compared to friction losses in long pipes.
3. What is the difference between major and minor losses?
Major losses occur due to pipe length (friction), while minor losses occur due to fittings and sudden changes in flow.
4. What are different types of minor losses?
Losses due to bends, valves, sudden expansion, sudden contraction, and pipe entrances and exits.
5. What causes minor losses?
They are caused by turbulence and disturbance due to changes in flow direction or area.
6. Write the general equation for minor loss.
hf = K V2/2g
7. What do each terms in the equation represent?
hf is head loss, K is loss coefficient, V is velocity, and g is acceleration due to gravity.
8. What is loss coefficient (K)?
It is a dimensionless factor that represents the amount of loss caused by a particular fitting.
9. Describe the apparatus used in this experiment.
The setup consists of a pipe with different fittings, pressure tapping points, a manometer, and a measuring tank.
10. What observations are recorded?
Pressure difference, discharge, and time taken to collect fluid are recorded.
11. How is head loss measured?
Head loss is calculated from pressure difference measured using a manometer.
12. Why do minor losses occur at fittings?
Because fittings cause sudden changes in flow direction or area, leading to turbulence and energy loss.
13. What factors affect minor losses?
They depend on flow velocity, type of fitting, and geometry of the pipe system.
14. What are sources of error in the experiment?
Errors may occur due to leakage, inaccurate readings, or unsteady flow conditions.
15. How can minor losses be reduced in pipelines?
They can be reduced by using smooth fittings, gradual bends, and proper pipe design.
Page updated
Google Sites
Report abuse