chapter 00 i_sem_2013_2014

CVEN 311 Fluid DynamicsCVEN 311 Fluid Dynamics 11

Hydraulics Engineering

By

Prof. Ajit Pratap Singh

Hydraulics Engineering

By

Prof. Ajit Pratap Singh

CE F312

First Semester 2013-2014

CE F312

First Semester 2013-2014

IntroductionIntroduction

� Aims

� to develop an understanding of how fluids

behave in a real, viscous, multi-dimensional

environment

� to show how that behaviour might be modelled

so as to provide useful data for applications.

� Aims

� to develop an understanding of how fluids

behave in a real, viscous, multi-dimensional

environment

� to show how that behaviour might be modelled

so as to provide useful data for applications.

Course LogisticsCourse Logistics

� Instructor-in-charge� Dr. Ajit Pratap Singh (CE F312)

� Instructor� Dr. Anupam Singhal

� Dr. Shibani K Jha

� Where can you get the latest updates?� CE F312 course web site: CMT, your bits email id

� Civil Engineering Notice Board

� Instructor-in-charge� Dr. Ajit Pratap Singh (CE F312)

� Instructor� Dr. Anupam Singhal

� Dr. Shibani K Jha

� Where can you get the latest updates?� CE F312 course web site: CMT, your bits email id

� Civil Engineering Notice Board

HomeworkHomework

� Your chance to practice using the concepts

presented in class

� Teamwork vs. Individual work?

� Answers will be provided in the assignment

sheets

� Guidelines in the class as well as at the web

site!!!

� Your chance to practice using the concepts

presented in class

� Teamwork vs. Individual work?

� Answers will be provided in the assignment

sheets

� Guidelines in the class as well as at the web

site!!!

Learning ResourcesLearning Resources

� Lecture

� Presentation of new material

� Example problems

� Homework

� Problem solving skills

� Lecture

� Presentation of new material

� Example problems

� Homework

� Problem solving skills


� Interaction in class and right after class

� Chamber Consultation hours

� Monday 9th Hour at 1227 (Dr. Ajit Pratap Singh)

� Tuesday 10th Hour at 1110-D (Dr. Anupam

Singhal)

� Wednesday 9th Hour at 1133-C (Dr. Shibani K

Jha)

� Walk in (if my door is open)

� Interaction in class and right after class

� Chamber Consultation hours

� Monday 9th Hour at 1227 (Dr. Ajit Pratap Singh)

� Tuesday 10th Hour at 1110-D (Dr. Anupam

Singhal)

� Wednesday 9th Hour at 1133-C (Dr. Shibani K

Jha)

� Walk in (if my door is open)



� Course notes

� from chalkboard

� supplemental materials on the web

� World Wide Web

� Check “link” for animations/movies

� Course notes

� from chalkboard

� supplemental materials on the web

� World Wide Web

� Check “link” for animations/movies

Assumed KnowledgeAssumed Knowledge

2nd

Year

Transport Phenomena I

Attendance PolicyAttendance Policy

� Attendance is highly recommended

� A sign-in sheet will be distributed in the

classes

� Attendance will be used as determining

factor when your grade is on the borderline

� Attendance is highly recommended

� A sign-in sheet will be distributed in the

classes

� Attendance will be used as determining

factor when your grade is on the borderline

Course TextCourse Text

� Modi, P.N. and Seth, S.M., Hydraulics and

Fluid Mechanics, Standard Book House, 18th

ed., 2011.

� T2. Fox, R.W. and McDonald, A.T.,

Introduction to Fluid Mechanics, John Wiley

and Sons Inc., Singapore, Eighth Edition, 2012.

� Moondra, H.S., Gupta, R., Lab. Manual for

Civil Engineering, CBS publishers & Dist, 2nd

ed., 2000

� Modi, P.N. and Seth, S.M., Hydraulics and

Fluid Mechanics, Standard Book House, 18th

ed., 2011.

� T2. Fox, R.W. and McDonald, A.T.,

Introduction to Fluid Mechanics, John Wiley

and Sons Inc., Singapore, Eighth Edition, 2012.

� Moondra, H.S., Gupta, R., Lab. Manual for

Civil Engineering, CBS publishers & Dist, 2nd

ed., 2000

IntroductionIntroduction

� Why do we care about fluids?

� Name 5 devices that required an

understanding of how fluids work in order

for the devices to be designed and built

� Why do we care about fluids?

� Name 5 devices that required an

understanding of how fluids work in order

for the devices to be designed and built

�Weather

�Design of Airplane and ships

�Water Distribution, wastewater treatment

facilities, dams and spillways

�Artificial heart

�Circulation of bloods in veins and arteries

�

Civil and Ocean FluidsCivil and Ocean Fluids

� What kinds of Civil and Ocean Engineering

projects require an understanding of fluids?

� What kinds of Civil and Ocean Engineering

projects require an understanding of fluids? �� Water Distribution SystemsWater Distribution Systems

��Pumps, Pipes, Tanks, ValvesPumps, Pipes, Tanks, Valves

�� Water/Wastewater Treatment PlantsWater/Wastewater Treatment Plants

�� Dams, Reservoirs, Hydropower, Dams, Reservoirs, Hydropower,

IrrigationIrrigation

�� Waste Discharges into the EnvironmentWaste Discharges into the Environment

�� High Rise BuildingHigh Rise Building

�� Coastal StructuresCoastal Structures


Dams and ReservoirsDams and Reservoirs Wastewater Treatment PlantsWastewater Treatment Plants

Water DistributionWater Distribution BridgeBridge

Offshore PlatformOffshore Platform My Goals for CourseMy Goals for Course

� That each of you develop an intuition for the fundamental Design principles of fluid mechanics

� That you leave this course saying, “Fluids makes sense” and “I can tackle fluids problems.”

� That we have an enjoyable semester learning together

� That each of you develop an intuition for the fundamental Design principles of fluid mechanics

� That you leave this course saying, “Fluids makes sense” and “I can tackle fluids problems.”

� That we have an enjoyable semester learning together


CMT for all lecture materials and

tutorials and solutions

http://cmt

Any queries email

[email protected]

Self Study StartsSelf Study Starts

Definition of a FluidDefinition of a Fluid

� “a fluid, such as water or air, deforms

continuously when acted on by shearing

stresses of any magnitude.”

� “a fluid, such as water or air, deforms

continuously when acted on by shearing

stresses of any magnitude.”

Water

Oil

Air

Why isn’t steel a fluid?

Water

Oil

Air

Why isn’t steel a fluid?

Viscosity Viscosity

� The viscosity is the property of fluid by

virtue of which a fluid it offers resistance to

deformation under the influence of a shear

force.

� It offers resistance to the movement of one

layer of fluid over another adjacent layer of

fluid.

� The viscosity is the property of fluid by

virtue of which a fluid it offers resistance to

deformation under the influence of a shear

force.

� It offers resistance to the movement of one

layer of fluid over another adjacent layer of

fluid.

Fluid Deformation between

Parallel Plates

Fluid Deformation between

Parallel Plates

Side viewSide view

Force F causes the top plate to have velocity U.Force F causes the top plate to have velocity U.

What other parameters control how much force is What other parameters control how much force is

required to get a desired velocity?required to get a desired velocity?

Distance between plates (b)Distance between plates (b)

Area of plates (A)Area of plates (A)

F

b

U

Viscosity!Viscosity!

Shear StressShear Stress

change in velocity with respect to distancechange in velocity with respect to distance

A

F=τ

2m

N

b

Uµτ =

b

U

dy

duµτ =

b

AUF µ= AU

Ft=µ

⋅2m

sNdimension of

s

1

Tangential force per unit area

Rate of angular deformation

rate of shear


Fluid classification by response

to shear stress

Fluid classification by response

to shear stress

� Newtonian

� Ideal Fluid

� Ideal plastic

� Newtonian

� Ideal Fluid

� Ideal plastic

NewtonianIdeal Fluid

Ideal plastic

Shear stress Shear stress ττ

Rat

e of

def

orm

atio

nR

ate

of

def

orm

atio

ndy

du

µµ

dy

duµτ =

1

Fluid Newton’s lawof viscosity

Non- Newtonianfluids

Do not obey

•The viscosity of the non-Newtonian fluid is dependent on thevelocity gradient as well as the condition of the fluid.

Newtonian Fluids� a linear relationship between shear stress and the velocity gradient (rate

of shear),� the slope is constant� the viscosity is constant

non-Newtonian fluids� slope of the curves for non-Newtonian fluids varies

Newtonian and Non-Newtonian

Fluid

Newtonian and Non-Newtonian

Fluid

If the gradient m is constant, the fluid is termed as Newtonian fluid. Otherwise, it is known as non-Newtonian fluid. Fig. 1.5 shows several Newtonian and non-Newtonian fluids.

Fluid ViscosityFluid Viscosity

� Examples of highly viscous fluids

� ______________________

� Fundamental mechanisms

� Gases - transfer of molecular momentum

� Viscosity __________ as temperature increases.

� Viscosity __________ as pressure increases.

� Liquids - cohesion and momentum transfer

� Viscosity decreases as temperature increases.

� Relatively independent of pressure (incompressible)

� Examples of highly viscous fluids

� ______________________

� Fundamental mechanisms

� Gases - transfer of molecular momentum

� Viscosity __________ as temperature increases.

� Viscosity __________ as pressure increases.

� Liquids - cohesion and momentum transfer

� Viscosity decreases as temperature increases.

� Relatively independent of pressure (incompressible)

molasses, tar, 20w-50 oil

increases

_______

increases

Role of ViscosityRole of Viscosity

� Statics

� Fluids at rest have no relative motion between

layers of fluid and thus du/dy = 0

� Therefore the shear stress is _____ and is

independent of the fluid viscosity

� Flows

� Fluid viscosity is very important when the fluid

is moving

� Statics

� Fluids at rest have no relative motion between

layers of fluid and thus du/dy = 0

� Therefore the shear stress is _____ and is

independent of the fluid viscosity

� Flows

� Fluid viscosity is very important when the fluid

is moving

zerozero

Dynamic and Kinematic

Viscosity

Dynamic and Kinematic

Viscosity

� Kinematic viscosity (__) is a fluid property

obtained by dividing the dynamic viscosity

(__) by the fluid density

� Kinematic viscosity (__) is a fluid property

obtained by dividing the dynamic viscosity

(__) by the fluid density

ρ

µν =

⋅=

3m

kg

sm

kg

ν

⋅⇒

2m

sNµ [ ]

⋅=

2s

mkgN

[m2/s]

Connection to Reynolds number!

n

µ

ρVDRe =

µ


Self Study Ends

Thank You

Self Study Ends

Thank You