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Fundamentals of Fluid

Mechanics

Lecturer: 1

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Ch.E-203 (Fundamentals of Fluid Mechanics)

Syllabus:

Introduction and importance of fluid mechanics; Description of Fluids; Types of

fluids and Classification of fluid flows; Compressible vs Incompressible fluids;Steady and Unsteady fluid flows; Properties of fluids; Basic Equations of fluid flow;Flow of incompressible fluids in pipes; Laminar and Turbulent flow in closedchannels; Processes of Compressible Fluid Flows; Flow through variable areaconduits; Boundry Layer Concept; Prandtl's Boundary Layers Equatons; TurbulentBoundary Layers; Dimensional Analysis.

Text and Reference Books:

1. McCabe Warren L., Smith Julian C., Harriott peter Unit Operations of ChemicalEngineering 6thEd. 2001. McGraw Hill Inc.

2. Coulson J.M., Richardson J.F. Chemical Engineering Vol-I, 1999. Butterworth,Elsevier.

3. White, F.M. Fluid Mechanics, 4thEdition, McGraw-Hill. 1999.4. Holland, F.A. Bragg, R. Fluid flow for Chemical Engineers, 2ndEdition, Butterworth

& Heinemann. 1995.

5. Noel-de-Nevers Fluid Mechanics for Chemical Engineers McGraw-Hill

6. Fundamental of Fluid Mechanics, 6th Edition.

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HISTORY

FACES OF FLUID MECHANICS

Archimedes(C. 287-212 BC)

Newton(1642-1727)

Leibniz(1646-1716)

Euler(1707-1783)

Navier(1785-1836)

Stokes

(1819-1903)

Reynolds

(1842-1912)

Prandtl

(1875-1953)

Bernoulli(1667-1748)

Taylor

(1886-1975)

http://www-gap.dcs.st-and.ac.uk/~history/PictDisplay/Taylor_Geoffrey.html

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Fluid Mechanics

What is mechanics?

Deals with the motion of bodies

What is fluid mechanics?

Study of the behaviour of gases and liquids.

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Importance of Fluid Mechanics?

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Classification of Fluid Mechanics

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Classification of Fluid Mechanics

Fluid statics

Fluid kinematics

Fluid dynamics

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Fluid Statics

Mechanics of fluids

at rest

in equilibrium

no shear stress

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Fluid Kinematics

Concerns with the motion of the fluids

Direction

Velocities

Streamlines

but

Without reference to forces which cause the motion

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Fluid Dynamics

Mecahnics of fluid

In motion

Fluids have some shear stress

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FluidAnything which can flow.

Any material or a substance that changes its shape or direction uniformly

on applying an external force to it.

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Classification of Fluids

Ideal fluids

Real fluids

Compressible fluids

Incompressible fluids

Newtonian fluids

Non-Newtonian fluids

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Newtons Law of Viscosity

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Shear stressShear rate

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Flow of fluid

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Velocity = max

Velocity gradient = 0

Shear stress = 0

Shear stress = max

Velocity = 0

Velocity gradient = max

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NEWTONIAN

Water

Most salt solutions in waterLight suspensions of dye

High-viscosity fuels

Gasoline

Kerosene

Most motor oils and mineral oils

PSEUDOPLASTIC

Sewage sludge

Paper pulp

Grease

SoapPaint

Printer's ink

Starch

Latex solutions

Most emulsions

DILATANT

Feldspar

Mica

ClayBeach sand

Starch in water

Bingham plastic

clay suspensions,

drilling mudtoothpaste

Mayonnaise

chocolate

mustard

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Reynolds NumberChange in flow depends upon four parameters

Diameter of tube through which liquid flows (D)

Density of the liquid (rho)

Average velocity of the liquid flowing (u)

Viscosity of the liquid (u)

Reynolds combine these four quantities in one dimensionless group.

The flow is

laminar when Re < 2300

transient when 2300 < Re < 4000

turbulent when 4000 < Re

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fluid flows in parallel layers

no disruption between the layers

No lateral mixing