CE 2134 Hydraulics

Dr. BAI WEI

Department of Civil and Environmental Engineering

National University of Singapore

Office: E1-05-21

Phone: 6516 2288

Email: w.bai@nus.edu.sg

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Background

CE2134 Hydraulics Introduction

Dam break

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River flows

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A ship travelling in a storm

Asymmetric impulsive wave

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Vortex shedding at Re = 2000

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Historical review

The Greeks produced quantitative information. Archimedes and Hero of

Alexandria both postulated the parallelogram law for addition of vectors

in the third century B.C. Archimedes (285212 B.C.) formulated the laws of buoyancy and applied them to floating and submerged bodies.

Problems involving the momentum of fluids could finally be analyzed

after Isaac Newton (16421727) postulated his laws of motion and the law of viscosity of the linear fluids now called newtonian.

Engineers began to reject what they regarded as a totally unrealistic

theory and developed the science of hydraulics, relying almost entirely

on experiment. Such experimentalists as Chzy, Pitot, Borda, Weber,

Francis, Hagen, Poiseuille, Darcy, Manning, Bazin, and Weisbach

produced data on a variety of flows.

At the end of the nineteenth century, unification between experimental

hydraulics and theoretical hydrodynamics finally began.

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Meanwhile, viscous-flow theory was available but unexploited, since

Navier (17851836) and Stokes (18191903) had successfully added newtonian viscous terms to the equations of motion.

Then, in 1904, a German engineer, Ludwig Prandtl (18751953), published perhaps the most important paper ever written on fluid

mechanics.

The twentieth century foundations for the present state of the art in fluid

mechanics were laid in a series of broad-based experiments and

theories by Prandtl and his two chief friendly competitors, Theodore

von Krmn (18811963) and Sir Geoffrey I. Taylor (18861975).

CE2134 Hydraulics Introduction

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Objective

Provide the most important footstone for your possible future study

related to the hydraulics.

Help to develop a rigorous logic, establish a scientific attitude, and treat

a problem from more mathematical point of view.

Share strategies for learning, thereby give you the tools to educate

yourself beyond the classroom.

My educational goal is when a former student stops by my office and

says to me Your class was hard but what I learned is now giving me a knife with a sharp edge.

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Basic flow-analysis techniques

There are three basic ways to attack a fluid-flow problem. They are

equally important for a student learning the subject:

Control-volume, or integral analysis

Infinitesimal system, or differential analysis

Experimental study, or dimensional analysis

It is possible to classify flows, but there is no general agreement on how

to do it. Most classifications deal with the assumptions made in the

proposed flow analysis. They come in pairs, and we normally assume

that a given flow is either

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References

JB FRANZINI & EJ FINNEMORE. FLUID MECHANICS WITH

APPLICATIONS.

ISBN 0-07-114214-2 WCB/McGRAW HILL (10th Ed)

YUNUS A CENGEL & JOHN M CIMBALA. FLUID MECHANICS FUNDAMENTALS & APPLICATIONS.

ISBN 978-007-128421-9 McGRAW HILL (2nd Ed)

ROBERT W FOX, PHILIP J PRITCHARD & ALAN T McDONALD.

INTRODUCTION TO FLUID MECHANICS.

ISBN 978-0-470-23450-1 John Wiley & Sons, Inc (7th Edition)

CE2134 Hydraulics Introduction