Chapter 1

Introduction to Fluid Mechanics and its

applications

Dr. Muhammad Ashraf Javid

Assistant Professor

Department of Civil and Environmental Engineering

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Fluid Engineering Mechanics

Fluid Engineering Mechanics Course

� Course: CIVL213, Fluid Engineering Mechanics� Credit Hours: (2 + 1) – 3 credits

� Course Synopsis: This course covers fluid properties,fluid thermodynamics, fluid statics, moving fluid concepts,force of moving fluid, flow in closed conduits, and analysisof fluid machines.

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FLUID MECHANICS

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� Recommended Books:

� 1. F. M. White, Fluid mechanics, Mcgraw-Hill (7th

Edition)

� Additional resources.

� 1. J. B. Franzini and Finnemore, Fluid Mechanics with Engineering Application, McGraw-Hill New York (Latest Edition)

� 2. Monson Young, Fundamentals of Fluid Mechanics, (Latest Edition)

� 3. Douglus, Fluid Mechanics, McGraw-Hill Inc.

� 4. Jack P. Fundamentals of Fluid Mechanics, McGraw-Hill Inc.

� 5. Merle Potter, Mechanics of Fluid, CL- Engineering (2011)

Course Topics

Introduction to Fluid Mechanics

Fluid characteristics

Fluid Statics

Fluid Thermodynamics

Concepts of Moving Fluids

Forces on Moving Fluids

Flow in Closed Conduits

Analysis of Fluid Machines

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Fluid Mechanics and Engineering Applications:

To Design water, oil and gas pipeline

Networks

To study Oceanography and Coastal Engineering

To Design Dams, Spillways, Hydraulic

Jumps

To study Water and Air

Pollution

To Design bridges across rivers

To design slabs that resist to water and groundwater

pressuresTo Design inshore Civil

infrastructure5

FLUID MECHANICS

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� Fluid: Fluids are substance which area capable of flowing andconforming the shapes of container.

� Fluids can be in gas or liquid states.

� Mechanics: Mechanics is the branch of science that deals withthe state of rest or motion of body under the action of forces.

� Fluid Mechanics: Branch of mechanic that deals with theresponse or behavior of fluid either at rest or in motion.

Branches of Fluid Mechanics

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� Fluid Statics: It is the branch of fluid mechanics which dealswith the response/behavior of fluid when they are at rest.

� Fluid kinematics: It deals with the response of fluid whenthey are in motion without considering the energies andforces on them.

� Hydrodynamics: It deals with the behavior of fluids whenthey are in motion considering energies and forces on them.

� Hydraulics: It is the most important andpractical/experimental branch of fluid mechanics whichdeals with the behavior of water and other fluid either at restor in motion.

Significance of Fluid Mechanics

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� Fluid is the most abundant available substance e.g., air, gases, ocean, river and canal etc.

� It provides basis for other subjects e.g.,

� Public health/environmental engineering

� Hydraulic Engineering

� Irrigation Engineering

� Coastal Engineering

� Water Resources

� Drainage structures in highways

� …………………. etc

State of Matter

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� 1. gas

� 2. Liquid

� 3. Solid

fluid

Comparison Between Liquids and Gases

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Liquids

� Liquids have definite volume at any particular temperature

� Liquids have free level surface

� Molecules of liquid are close to each other

� Liquids have relatively more molecular attraction

� Liquids are slightly compressible

� Rate of diffusion of liquid is less

Gases

� Gases do not have any definite volume

� Gases do not have free level surface

� Molecules of gases are far apart

� Gases have less molecular attraction

� Gases are highly compressible

� Gases have higher rate of diffusion

Comparison Between Liquids and Solids

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Liquids

� Liquid conform the shape of any container

� Liquid can flow

� Molecules of liquid are distinctly apart

� Liquids have relatively less molecular attraction

� Liquids are slightly compressible

� Liquids cannot sustain shear forces

Solids

� Do not conform the shape of container

� Solids cannot flow

� Molecules of solids are very close to each other

� Solids have more molecular attraction

� Solids are highly incompressible

� Solids can sustain shear

Dimensions and Units

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� System of Units

� System International (SI)

� Fundamental dimensions: length, mass and time

� Units: (meter, kilogram and second)

� British Gravitation System (BG)

� Fundamental dimension: length, force and time

� Units: (ft, pound and second)

� CGS System

� Fundamental dimensions: length, mass and time

� Units: (centimeter, gram and second)

Dimensions and Units

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� Dimensions

� Fundamental/Primary Dimension

� length(L), mass (M) and time (T)

� Derived/Secondary Dimensions

� e.g., force, velocity, acceleration etc

Fundamental/Primary Dimension

Units of Some Dimensions in Different Systems

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System

Length Time Force Velocity Acceleration

Energy Power Temperature

SI m s N m/s m/s/s N-m N-m/s oC

BG ft s lb ft/s ft/s/s ft-lb ft-lb/s oF

CGS cm s dyne cm/s cm/s/s dyne-cm

dyne-cm/s

oC

� Fundamental Units

� length(L), mass (M) and time (T)

� Derived Units

� e.g., force(F), velocity(L/T), acceleration (L/T/T) etc

Important Prefixes

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� e.g.,

� Force=1000000N

=1000KN

=1MN

Diameter=0.000001m

=1µm

Primary and Secondary Dimensions

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Conversions

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� Length

� 1m=1000mm=100cm

� 1ft=12inch

� 1m=3.281ft

� 1Mile=5280ft=_______km

� Time

� 1day=24hours

� 1 hour=60min

� 1 min=60s

� Mass

� 1kg=1000g

� 1kg=2.204lb

� 1kg=9.81N

� 1N=0.2246 lb

� Volume

� 1m3=1000liters=_______cm3

� 1m3=35.32ft3

Unit Conversion

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� It is the process of relating dimensions of a quantity from one system to another. e.g.,

� (i) 1m = 3.281 ft

� (ii) 1kg = 2.204 lb

� Exercise: Convert the units of following.

� 60 miles/hour=_________ ft/s=___________m/s=____________km/hr

� 10m3/s=________liter/min=__________ft3/s=____________ in3/s

� 15N/m2=___________N/cm2=______________lb/ft2

Sample MCQs

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� (i). Fluids do not conform the shape of container they are placed in.

� (True/False)

� (ii). Unit of force in SI is ____________.

� (a). Newton (b). Pound (c). Kg (d). dyne

� (iii). Convert 2 kg/m3 to _____lb/ft3.

� (iv). Branch of fluid mechanics that deals response of fluid at rest is called

� (a) Fluid Dynamic (b). Fluid kinematics (c). Fluid statics (d). Hydraulics

� (v). Fluid are absolutely not compressible.

� (True/False)

� (vi). Write name of any text book on fluid mechanics along with author name. Answer:___________________________________