Me1202 - Fluid Mechanics Machineries

7/29/2019 Me1202 - Fluid Mechanics Machineries

1/122


2/122

Department of Mechanical Engineering S Mechanical Engineering ME1202 -FLUID MECHANICS & MACHINERIES 3TWO MARK QUESTIONS Module I(Introduction) 1. Define fluid? A fluid is a substance having a property to flow easily. Example:liquid, vapour, gas. 2. Define fluid mechanics? Fluid mechanics is a branch of science which dealswith property and behaviour of fluids at rest and in motion. 3.Define fluid statics? The study offluids at rest is called fluid statics . 4.Define fluid kinematics? The study of fluids in motion wherepressure forces are not considered is called fluid kinematics. 5.What is the SI unit of density ?The SI unit of density is kg/m3. Example: Density of water is 1000 kg/m3. 6.Define specific volume?3 It is the ratio of volume to the mass of a fluid. It is denoted by .Its unit is m/kg. =volume of fluid Mass of fluid =V/m m3/kg 7. Define specificgravity with respect to density? It is the ratio of density of a fluid to density of a standardfluid. It is denoted by s. i.e, s = density of liquid density of waters = density of gas density of air 8.Define viscosity? Itis defined as the resisting property of liquid to its flow corresponding to its adjacent layers. 9. Whichone of the following has high viscosity, (i) water or (ii) lubricating oil? Lubricating oil hashigh viscosity. 10. Define poise ? Poise is the other name of unit of viscosity in CGS systemwhich equals dyne-sec/cm2. 11.Give the classification of fluids? Classification of fluidsare, (i)Ideal fluid (ii)Real fluid (iii)Newtonian fluid (iv)Non Newtonian fluid (v)Ideal plastic fluid.


3/122

12. What is real fluid? A fluid which hasviscosity is a real fluid. All fluid in practice are real

fluids. 13.What is non Newtonian fluid? A

real fluid in which shear stress is not proportional to rate

of shear strain. t .du

dy t = Shear stress = viscosity of the fluid du =

change in velocity dy = change in perpendicular distance.

14.What is compressibility? Compressibility is the

property of fluid which undergoes change in volume

under various pressure conditions. 15. Define

compressible fluid? A liquid is considered

to a compressible fluid only when there is a change in

volume of liquid that occurs under large pressure variation

. 16. Define compressibility? It is also

defined of reciprocal of bulk modulus of elasticity (k).

i.e, compressibility = 1/k . k=

compressive stress / volumetric strain 17.Define

capillarity? It is the phenomenon of rise or

fall of liquid surface relative to out side liquid surface

18.Give the types of gas laws? The types of

gas laws are, (i)Boyles law (ii)Charles law 19.

Give the equation for capillarity fall in an glass tube.

The equation for the capillarity fall is

h = 4scos metre.

gd 20. Give some properties of fluid?

Some properties of fluids are density, specific weight,

viscosity, surface tension and capillarity 21. Define

fluid dynamics? The study of fluid in motion

where pressure forces are considered is called as fluid

dynamics. 22. Define density or mass density?

Density is the ratio mass of a fluid to its volume it is


4/122

denoted by . m\v kg/m=3 23. Define specific weight or weight density ?Specific weight is defined as the ratio of weight of fluid

to its volume .


5/122

Its unit is N/m3. i.e,w = W/V N/m3 24.Define specificgravity with respect to weight density?

It is the ratio of specific weight of fluid

to specific weight of a standard fluid .

i.e, s = specific weight of liquid

(for liquids) specific

weight of water i.e, s =specific weight of gas (for

gasses) specific weight

of air 25.Define dynamic viscosity?

The shear stress required to move one

layer with unit velocity over another layer

at unit distance .It is known as dynamic

viscosity .It is denoted as 26.Givethe other names of dynamic viscosity ?

The other name of dynamic viscosity are

(i)absolute viscosity and (ii)co efficientof viscosity . Its unit is Ns/m2. 27.Give the units of viscosity in (i)

MKS (ii) CGS and (iii) SI systems?

The units of viscosity in (i)MKSsystem is kgf-sec/m2. (ii)CGS system isdyne-sec/cm2. (iii)SI system is Ns/m2.28. Give equivalent values for poise in

SI units and CGS unit system?

Equivalent value in SI unit,

one poise =1/10 Ns/m2 CGSsystem, one poise = dyne sec. / cm2.29.What is cause for viscosity?

The causes for the viscosity are (i)intermolecular force of cohesion and (ii)moment of molecules being exchanged .

30.Define ideal fluid? A fluid

which is incompressible and has no

viscosity is called as an ideal fluid . It is

an imaginary fluid . 31. Define

Newtonian fluid? A real

fluid in which shear stress is directlyproportional to the rate of shear strain.

t = . du/ dy 32. Define ideal

plastic fluid ? A fluid whose

shear is more than yield value and its

shear stress is directly proportional to

shear strain is called as ideal plastic fluid.

33.What is an incompressible fluid?

A liquid is considered to be

incompressible only when there is a


6/122

change in volume of a liquid that occurs

under smaller pressure variation.


7/122

34.Give some example of surfacetension ? Some examples of

surface tension are , (i) coins

when placed over liquid gently floats and

gives a spherical shape (ii)

molten lead particles while descending

spherical shape (iii) falling droplet of

rain water gives spherical shape 35. Givesome examples of capillarity?

Some examples of capillarity are 1)Riseof shape in tree. 2)Rise of kerosene

through wick. 36. Give the

equation for capillarity in a glass tube?

The equation for capillarity is h=4cos/wd 37. Define vapour

pressure? When evaporation takes place

within enclosed surface the partial pressure

created on the liquid surface by the vapourmolecules is called as vapour pressure

38. Define Boyles law? Boyles law for a

given quantity of gas constant temperature

pressure is inversely proportional to its

volume. It is denoted as P 1/v at constant t

:pv= a constant V 1/p at constant t

39.Define Avogadros law? Avogadros

law states that equal volume of gases at the

same temperature and pressure contains

equal number of molecules. It is given by

pv=nRT Where r gas constant N Avogadro

number 40.Define surface

tension. It is defined as the

tangential force per unit length acting at

right angles on

either side of the surface. It is denoted by

s. Its unit is N/m.


8/122

41.Give the equation for the effect of

surface tension on a liquid droplet.

The equation is given by P = 4sd where P = pressure

intensity inside the droplet.

s = surface tension of liquid.

d = diameter of droplet. 42.Give the

equation for effect of surface tension ona hollow bubble. The

equation is P = 8s/d where P = pressureintensity inside the droplet.

s = surface tension of liquid.

d = diameter of droplet. 43. Give the

equation for effect of surface tension on

a liquid jet. The equation

is P = 2s/d 49. Give the equation for

capillarity fall in an glass tube.

The equation for the capillarity fall ish = 4scos metre.gdThe causes for viscosity are,

1.inter molecular force of cohesion and

2. moment of molecules being exchanged.

48.What is an incompressible fluid? en

there is a change in volume of a liquid that

occurs under smaller pressure variationA

liquid is considered to be incompressible

only wh. where P = pressure intensity

inside the droplet. s =surface tension of liquid. d = diameter of

droplet. 44.Define capillarity. It is

defined as the phenomenon of rise or fall

of liquid surface relative to outside liquid

surface. 45.Define Charles law.

Charles law for a given quantity of gas at

constant pressure, the volume varies

directly with absolute temperature. v a Tat constant P.

46.Give the values for angle of contactfor (1) mercury and glass tube (2) water

and glass tube.

The values for the angle of contact for,(1)mercury and glass tubes = 128(2) water and glass tubes = 0


9/122

47.What are the causes for viscosity?

Module VI (Positive Displacement

Machines) Reciprocating pump. 1)

Define pump? It is defined as the

hydraulic machine in which converts the

mechanical energy into hydraulic energy,

which is mainly in the form of pressure

energy. 2) What is the main parts ofreciprocating pump? 1.A cylinder

with a piston, Piston rod, connecting rod

and a crank. 2.Suction pipe, Delivery

pipe. 3.Suction valve and

4.Delivery valve. 3) What is the slip in

reciprocating pump? Slip is the

difference between the theoretical

discharge and actual discharge of the

pump. Slip= Qth-Qact.

4) Why negative slip occures in

reciprocating pump? If actual

discharge is more than the theoretical

discharge the slip of the pump will be

negative. Negative slip occurs only when

delivery pipe is short, Suction pipe is long

and pump is running at high speed. 5)

How will you classify the reciprocating

pump? The reciprocating pump may be

classified as, 1.According to the water

in contact with one side or both sides of

the piston. 2.According to the number

of cylinders provided. Classification

according to the contact of water is (1)

Single acting (2)Double acting. According

to the number of cylinders provided they

are classified as, 1.Single Cylinder

pump. 2.Double cylinder pump.

3.Triple cylinder pump. 6) What is single

acting pump and double acting pump?

If the water is in contact with one side of

the piston the pump is known as singleacting pump, On the other hand if the

water is in contact with both sides of the

piston the pump is called double acting

pump. 7) Define indicator diagram?

The indicator diagram for a reciprocating

pump is defined as the graph drawn

between the pressure head in the cylinder

and the distance traveled by the piston

from inner dead center for one complete


10/122

revolution of the crank. 8) Define ideal

indicator diagram? It is defined as

the graph between pressure head in the

cylinder and stroke length of the crank

under ideal condition is known as ideal

indicator diagram. 9) What is an air

vessel? An air vessel is a closed

chamber containing compressed air in thetop portion and liquid at the bottom of the

chamber. At the base of the chamber there

is an opening through which the liquid

may flow into the vessel or out of the

vessel.


11/122

10

)

W

ha

t

is

th

epu

rp

os

e

of

an

air

ve

sse

l

fit

te

d

in

th

e

pu

m

p?

1.T

o

ob

tai

n a

co

nti

nu

ou

s

supp

ly

of

liq

ui

d

at

a


12/122

un

ifo

rm

rat

e.

2.

To

sa

ve

a

co

nsi

de

ra

ble

am

ou

nt

ofwo

rk

in

ov

erc

o

mi

ng

the

fri

cti

on

al

res

ist

an

ce

in

the

su

ction

an

d

del

ive

ry

pi

pe


13/122

s,

an

d

3.

To

ru

n

the

pu

m

p

at

a

hi

gh

sp

ee

d

with

ou

t

se

pa

rat

io

n.

11

)

W

ha

t

is

th

e

wo

rk

sa

ved

by

fit

tin

g

a

air

ve


14/122

sse

l

in

a

sin

gle

ac

ting ,

do

ub

le

ac

tin

g

pu

m

p?

W

or

k

sa

ve

d

by

fitt

in

gair

ve

sse

ls

in

a

sin

gle

act

in

gpu

m

p

is

84

.87

%,

In


15/122

a

do

ub

le

act

in

g

pu

m

p

the

wo

rk

sa

ve

d

is

39

.2%.

12

)

De

fin

e

co

eff

ici

ent

of

dis

ch

ar

ge

of

re

ci

pr

oc

ati

ng

pu

m

p?

It


16/122

is

de

fin

ed

as

the

rat

io

of

act

ual

dis

ch

arg

e

to

the

or

etical

dis

ch

arg

e

of

rec

ipr

oc

ati

ng

pu

m

p.

cd

=

Qa

/Q

th.

13

)De

fin

e

ce

nt

rif

ug

al


17/122

pu

m

p?

It

is

de

fin

edas

a

de

vic

e,

wh

ich

co

nv

ert

sme

ch

ani

cal

en

er

gy

in

the

hy

dr

aul

ic

en

er

gy

by

me

an

s

ofce

ntr

ifu

gal

for

ce

act

in


18/122

g

in

the

cyl

in

der

.

14

)

W

ha

t

is

pr

im

in

g?

Primi

ng

is

a

pr

oc

ess

of

fill

in

gup

wa

ter

in

the

ca

sin

g

an

d

su

cti

on

pi

pe

of

the

ce

ntr


19/122

ifu

gal

pu

m

p

for

the

re

mo

val

of

air

bef

or

e

sta

rti

ng

it.15

).

W

ha

t

is

Di

sc

ha

rge

th

ro

ug

h

a

Re

ci

pr

oc

ati

ng

Pu

m

p

in

Pe


20/122

r

se

c ?

Fo

r

Si

ng

leact

in

g

Di

sc

ha

rge

(Q

)=

A

LN/

60

W

he

re

A

=

Ar

ea

of

the

Cy

cli

nd

er

in

mL=

Le

ng

thof

Str

ok

e

in

m.

N

=S


21/122

pe

ed

of

Cr

an

k

in

RP

M

Fo

r

Do

ub

le

act

in

g

Q

=2A

L

N/

60

2

16

).

W

ha

tis

th

e

W

or

kd

on

e

by

Reci

pr

oc

ati

ng

Pu

m

p


22/122

Pe

r

se

c.?

W

or

kd

one

=

gA

L

N(

hs+h

)/6

0

(fo

r

sin

gle

act

in

g)

Fo

r

Do

uble

act

in

g:

W

or

k

do

ne

=

2gA

L

N(

hsd+h

)/6

0


23/122

W

he

re

d=De

nsi

ty

of

W

ate

r

in

kg

/m

3A

=

Area

of

the

Cy

cli

nd

er

in

m2L=

Le

ng

th

of

Str

ok

e

in

m

N=S

pe

ed

in

rp

m

h,h


24/122

=S

uct

io

n

an

d

De

liv

er

y

he

ad

in

m

sd17

).

W

hat

is

th

e

Pr

ess

ur

e

he

ad

du

e

to

ac

cel

er

ati

on

in

th

e

Su

cti

on

&

De

liv


25/122

er

y

Pi

pe

?

hf2=4fl(

A/

a*

rsin

)/2g

d

W

he

re

f=

Co

-

eff

ici

ent

of

fri

cti

on. A

=

Ar

ea

of

pis

to

n

in

m2.a

=

Ar

ea

of

pi

pe

in


26/122

m2. =An

gu

lar

sp

ee

d

r =

Ra

di

us

of

cra

nk


27/122

19

).

W

ha

t

is

th

erel

ati

on

be

tw

ee

n

W

or

k

do

ne

of

a

Pu

m

p

an

d

Ar

ea

of

In

di

ca

to

r

Di

agra

m

?

W

or

k

do

ne


28/122

by

the

pu

m

p

is

Pr

op

ort

io

nal

to

the

are

a

of

the

In

dicato

r

dia

gr

am

.

20

).

W

ha

t

is

th

e

W

or

k

do

ne

byth

e

Pu

m

p

pe

r

se


29/122

c

du

e

to

ac

cel

er

ation

an

d

fri

cti

on

in

th

e

su

cti

on

an

d

de

liv

er

y

Pi

pe

s ?

Fo

r

sin

gle

act

in

g

W

=gA

L

N(

hs

+h

d+

0.6


30/122

7h

fs

+0

.67

hf

d)/

60

Fo

r

Do

ub

le

act

in

g

W

=2

g

AL

N(

hs

+h

d+

0.6

7h

fs

+0

.67

hf

d)/

60

W

he

re

hfs

,

hf

d

=los

s

of

he

ad

du

e

to


31/122

ac

cel

era

tio

n

in

the

su

cti

on

an

d

del

ive

ry

Pi

pe.

21

).W

ha

t

is

th

e

M

ea

n

Ve

loc

ity

of

Si

ng

le

ac

tin

g

re

ci

pr

oc

ati

ng

pu

m


32/122

p

?

v=

Ar/3

.14

a

Whe

re

=

An

gu

lar

vel

oci

ty

inra

d/s

ec

r

=R

adi

us

of

the

crank

in

m

A

an

d a

=

Ar

ea

of

cylin

de

r

an

d

Pi

pe

in


33/122

m2


34/122

Module-III (Flow ThroughCircular Conduits)VISCOUS FLOW,TURBULENT FLOW&FLOW THROUGHPIPES 1) What do youmeant by viscous flow ?A flow is said to beviscous if the Renoldsnumber is less than 2000(or) the flows in layersie. R


35/122

number is less than 2000

is known as Laminar flow.

Renolds number is greater

than 4000 is known as

Turbulent flow . 2)

Laminar flow is possible

only at low velocities and

high viscous fluids . 2)

Is the flow is possible at

both velocities and low

viscous fluid . 3) In

such type of flow fluid

particle moves in laminas

or layers gliding smoothly

over the adjacent layer .

3) In that type of flow

fluid particle move in a

zig zag manner . 8)

What is the expression

for head loss due to

friction in Darcy

formula ?

hf 2= 4fLV 2gDWhere /f = Coefficient of

friction in pipe L =

Length of the pipe D =

Diameter of pipe

V = velocity of the fluid

9) What are the factors

influencing the frictional


36/122

loss in pipe flow ?

Frictional resistance for the

turbulent flow is

i.Proportional to vnwhere v varies from 1.5 to

2.0 . ii.Proportional to the

density of fluid . iii.

Proportional to the area of

surface in contact . iv.

Independent of pressure .

v.Depend on the nature of

the surface in contact .

10) What are the factors

to the determined when

viscous fluid flows

through the circular pipe

? The factors to

the determined as

i.Velocity distribution

across the section . ii.

Ratio of maximum

velocity to the average

velocity . iii.Shear stress

distribution . iv.Drop of

pressure for a given

length . 11) Give the

equation for average

velocity : - The

equation for average

velocity is given as

U = p (-/x 2)R Where R = Radius


37/122

of the pipe

12) Give the formula for

velocity distribution: -

The formula for velocity

distribution is given as U

= (-p/x ) (R22-r) Where R = Radius ofthe pipe r

= Radius of the fluid

element 13) What do

you understand by the

terms a) major energy

losses , b) minor energy

losses Major energy

losses : - This loss due to

friction and it is calculated

by Darcy weis bach

formula and chezys

formula .


38/122

Minor energy losses :- This is due to i.Sudden expansion inpipe . ii.Sudden contraction in pipe . iii.Bend in pipe . iv.Due to obstruction inpipe . 14) How will you determine the loss of head due to friction in pipes?Darcy weis-bach hf 2= 4fLV 2gD Wherehf = /Loss of head due to friction . f = Coefficient offriction in pipe . D = Diameter of pipe .L = Length of the pipe V = Meanvelocity of flow . Chezys formula V = C miWhere i = h/ l f15) Give an expression for loss of head due to suddenenlargement of the pipe :- he = (V1-V22)/2g Whereh = Loss of head due to sudden enlargement of pipe . Ve = Velocity of flowat section 1-1 V1 = Velocity of flow at section 2-2 216) Give anexpression for loss of head due to sudden contraction : - hc 2 =0.5 V/2gWhere h= Loss of head due to sudden contraction .V = Velocity at outlet of pipe. c 17) Give an expression for loss of head atthe entrance of the pipe : - hi2 =0.5V/2g where hi =Loss of head at entrance of pipe . V = Velocity of liquid at inlet and outlet ofthe pipe . 18) Derive the expression for drop of pressure for a given lengthof a pipe :- P Where 1-P2 = 32 UL/ gD 2


39/122

P1-P is drop of pressure . 2 19) Give expressionfor co efficient of friction in terms of shear stress :- f = 2 0/ v 2Where = Shear stress

v = volume of pipes f = coefficient of friction

0 20) Give an expression for loss of head due to an obstruction in pipe

Loss of head due to an obstruction = V2/2g ( A/Cc2 (A-a ) -1 )Where A = area of pipe

a = Max area of obstruction V =

Velocity of liquid in pipe A-a = Area of flow of

liquid at section 1-1 21) Define the terms a) Hydraulic

gradient line [HGL] b) Total Energy line

[TEL] a) Hydraulic gradient line :- Hydraulic gradient

line is defined as the line which gives the sum of pressure head and datum

head of a flowing fluid in apipe with respect the reference line . b)

Total energy line :- Total energy line is defined as the line

which gives the sum of pressure head , datum head and kinetic head of a

flowing fluid in a pipe with respect to some reference line . 22) What is

sypon ? where it is used :_ Sypon is along bend pipe which is

used to transfer liquid from a reservoir at a higher elevation to another

reservoir at a lower level . Uses of sypon : - 1.To carry

water from one reservoir to another reservoir separated by ahill ridge . 2.

To empty a channel not provided with any outlet sluice . 23)

What is the intensity of pressure rise due to water hammer ?

Water hammer in pipe is given by P = LV/t = When the valve is

closed gradually = V vKP = when the valve is closed suddenly and

pipe is assumed rigid . = V v /1/K + D/Et = when valve is closed

suddenly and pipe is elastic . 24) What is meant by hydraulic mean

depth ? or hydraulic radius :- It is the ratio between area of flow

to the wetted perimeter of pipe . Hydraulic mean depth m =

A/P = p/4 d/p d = d/4 2


40/122

m= d/4 25) What does the pressurerise due to water hammer in pipes depends on? It depends onVelocity of flow of water in pipe . The length of the pipe . Time taken toclose the valve . Elastic properties of the material of the pipe .26) What is the condition for maximum power transmitted through anozzle ? hf = H /3 It states that powertransmitted through nozzle is maximum when loss of head due to frictionin pipe is one third of the total head supplied at the inlet of pipe . 27 )What are the basic educations to solve the problems in flow throughbranched pipes? i.Continuity equation . ii. Bernoullisformula . iii. Darcy weisbach equation . 28 ) What is Dupuitsequation ? L1/d1 5+L Where L2/d1,d2 51 +L3/d3 5 = L /d5 = Length and diameter of the pipe 1L2, d= Length and diameter of the pipe 2 L3,2 d =Length and diameter of the pipe 3 3


41/122

Mo

dul

e-II

(Fl

uid

Flow

Co

nce

pts

and

Bas

ic

Eq

uati

ons

) 1)Defi

ne

forc

ed

vert

ex

flow

?

Give

exa

mpl

e?

It is

defi

ned

as

thattype

of

verte

x

flow

in

whic

h

som


42/122

e

exter

nal

torq

ue is

requ

ired

to

rotat

e the

fluid

mass

.

Exa

mple

. 1.A

verti

cal

cylinder

cont

ainin

g

liqui

d

whic

h is

rotat

ed

abou

t its

centr

al

axis

with

a

cons

tant

angu

larvelo

city.

2.Fl

ow

of

liqui

d

insid

e the


43/122

impe

ller

of a

cent

rifug

al

pum

p.

2)Defi

ne

free

vert

ex

flow

?

Give

exampl

es?

Whe

n no

exter

nal

torq

ue is

requ

ired

to

rotat

e the

fluid

mass

,that

type

of

flow

is

called

free

verte

x

flow

.

Exa

mple

.


44/122

1.Flo

w of

liqui

d

thro

ugh

a

hole

prov

ided

at

the

bott

om

of a

cont

ainer

. 2.A

whirlpoo

l in a

river

. 3)

Wri

te

the

equ

atio

n ofmoti

on

for

vert

ex

flow

?

dp=

(v2/r)dr-

gdz

This

the

equa

tion

of


45/122

varia

tion

of

pres

sure

of a

rotat

ing

fluid

in

any

plan

e.

Whe

re

r-

Radi

us of

element.

p-

Pres

sure

varia

tion.

-dens

ity

of

liqui

d.

g-

Acc

elera

tion

due

to

grav

ity.

4)Wri

te

the

equ

atio

n of

forc

ed


46/122

vort

ex

flow

?

Z=(

22r)/2gWhe

re

-Ang

ular

velo

city.

r-

Radi

us of

parabola.

z-

Heig

ht of

para

bola.

g-

Acc

elera

tiondue

to

grav

ity.

5)

Wri

te

the

equ

atio

n of

clos

ed

cyli

ndri

cal

vess

els?

Z=(


47/122

22r)/2g

Volu

me

of

air

befo

re

rotat

ion=

Volu

me

of

clos

ed

vess

el-

Volume

of

liqui

d in

vess

el.

Volu

me

of

air

afterrotat

ion=

Volu

me

of

para

bolo

id

form

ed.6)

Wh

at

are

the

forc

es

pres

ent


48/122

in a

flui

d

flow

?

Fg-

Grav

ityforc

e

Fp-

Pres

sure

forc

e

Fv-

Forc

e

due

to

visc

osity

Ft-

forc

e

due

to

turb

ulence.

Fc-

Forc

e

due

to

com

pres

sibil

ity.

7)Give

the

Eule

rs

equ

atio

n of

moti


49/122

on?


50/122

(dp/)+gdz+vdv=08)WhataretheassumptionsmadeinderivingBernouilliesequation?1.Thefluidisideal2.Theflowissteady.3.Theflowisincompressible.4.Theflowisirrotational.9)Whatisbernouilliesequationforrealfluid?(p112/g)+(v/2g)+z1=(p22 2/g)+(v/2g)+z2+hwherehlisthelossofenergy(p/g)-Pressureenergy.(v2/2g)=Kineticenergy.z-Datumenergy.l10)StatetheapplicationofBernouilliesequation?Ithastheappli


51/122

cationonthefollowingmeasuringdevices.1.Orificemeter.2.Venturimeter.3.Pitottube.11)Defineventurimeter?Aventurimeterisadeviceusedformeasuringtherateofflowofafluidflowingthroughapipe.Itconsistsofthreeparts,Theyareshortconvergingpart ,andthroatadivergingpart.12)Writetheexpressionforrateofflowthroughventurimeter?DischargethroughventurimeterisgivenbyQ=cactualda1a2(2gh)^1/21 2/(a2 2-a1/2)^Wherecd-Co-efficientofventurimetera1-are


52/122

aofinleta2-areaofthroat.h-differenceinpressureheadsattheinletandatthethroat.g-accelerationduetogravity.13)Whatpurposeorificemeterisused?Defineit?Itisadeviceusedformeasuringtherateofflowofafluidthroughapipe.Orificemeterconsistofaflatcircularplatewhichhas acircularsharpedgedholecalledorificemeter.14)Statemomentumequa

tionandImpulsemomentumequation?Themomentumequationstatesthatnetforceactingon


53/122

afluidmassinequaltothechangeinmomentumpersecondindirection.ThisisgivenasF=d(mv)/dtTheimpulsemomentumequationisgivenbyF.dt=d(mv)15)Statemomentofmomentukmequation?


54/122

Themomentofmomentumequationstatesthattheresultanttorqueactingonarotatingfluidisequaltorateofchangeofmomentofthemomentum.Mathematicallyitisgivenas.T=pq(v2r2-v1r)116)Definepitottubeandgiveitsworkingprinciple?Thepitottubeconsistofaglasstubebentatrightangles.It isbasedontheprinciplethat ifthevelocityofflowatapointbecomeszerothepressurethereisincreasedduetoconversionofkineticenergyintopressureenergy.17)Deriv


55/122

eanequationfortheresultantforceexertedbyaflowingfluidonapipebend?F=PQ(vx1-v2cos)+Pcos.F=PQ(-vy2sin)-P21AA22-P2Asin.Resultantforce=(Fx2+Fy 2)^1/22Andtheanglemadebytheresultantforcewithhorizontaldirectionisgivenby18)StateBernouilliestheorem?Itstatesthatinasteadyidealflowofanincompressiblefluidthetotalenergyatany

pointofthefluidisconstant.Thetotalenergyconsistsofpressureenergy,Kineticenergyandpotentialen


56/122

ergy.19)Givetheexpressionforactualvelocityinpitottube?(v1)=c(2gh)^

v1/2c-Co-efficientofpitottube.(vv)act-Actualvelocity.(2gh)^11/2-Theoriticalvelocity.20)Whatarrangementsshouldbeadoptedtofindthevelocityatanypointinapipebyapitottube?Thearrangementstobeadoptedare(1)Pitottubealongwithverticalpiezometertube.(2)Pitottubeconnectedwithpiezometer.(3)PitottubeandverticalpiezometerconnectedwithadifferentialU-tubemanometer.21


57/122

)Whatarethetypesoffluidflows?Thefluidflowisclassifiedas,(1)Steadyandunsteadyflow.(2)Uniformandnon-uniformflow.(3)Laminarandturbulentflow.(4)Compressibleandincompressibleflow.(5)Rotationalandirrotationalflow.(6)One,twoandthreedimentionflow.


58/122

22

)

Di

ffe

re

nti

at

este

ad

y

an

d

un

ste

ad

y

flo

w?

St

ea

dy

flo

w

Un

ste

ad

yflo

w.

1.S

tea

dy

flo

w

is

de

fin

ed

as

tha

t

ty

pe

of

Un

ste

ad


59/122

y

flo

w

is

tha

t

ty

pe

of

flo

w

in

flo

w

in

wh

ich

the

fluid

ch

ara

cte

ris

tic

s

wh

ich

the

vel

oci

ty.

pr

ess

ur

e

at

a

po

intlik

e

vel

oci

ty,

pr

ess

ur

e


60/122

etc

at

a

po

int

do

ch

an

ge

s

wi

th

ti

me

.

no

t

ch

ange

wi

th

ti

me

2.

(d

v/

dt)

(0,0,0)=0

(d

v/

dt)

=/

0

23

)

Di

ffe

re

nti

at

e

un

ifo

r


61/122

m

an

d

no

n-

un

ifo

rm

flo

w?)

(0,0,

0Un

ifo

rm

flo

wNo

n-

un

ifo

rm

flo

w.

1.I

t is

de

fin

ed

as

tha

t

ty

pe

of

flo

w

Itis

de

fin

ed

as

tha

t

ty

pe


62/122

of

flo

w

in

wh

ich

in

wh

ich

the

vel

oci

ty

at

an

y

giv

en

thevel

oci

ty

at

an

y

giv

en

ti

me

ch

an

ge

s

wi

th

ti

me

do

es

not

ch

an

ge

wi

th

res

pe

ct


63/122

res

pe

ct

to

ti

me

.

to

sp

ac

e.

2.

(d

v/

dt)

t=co

nsta

nt=0(d

v/

dt)

=/

0

24

)

Di

ffe

renti

at

e

la

mi

na

r

an

d

turb

ul

en

t

flo

w?t=co

nsta

nt


64/122

La

mi

na

r

flo

w.

Tu

rb

ula

nt

flo

w.

1.

La

mi

na

r

flo

wis

de

fin

ed

as

tha

t

ty

pe

It

is

de

fin

ed

as

tha

t

ty

pe

of

flow

in

wh

ich

of

flo

w

in

wh


65/122

ich

the

flu

id

pa

rti

cle

mo

ve

the

flu

id

pa

rti

cle

mo

ve

s

inazig

-

za

g

wa

y

alo

ng

we

ll

de

fin

ed

pat

h

or

str

ea

ml

ine

and

all

the

str

ea

ml

ine

are

str


66/122

aig

ht

an

d

pa

ral

lel.

2.

Re

yn

ol

ds

nu

m

be

r

40

00

.

25

)

De

fin

e

c

m

pr

ess

ibl

e

flo

w?

Co

m

pr

ess

ibl

e


67/122

flo

w

is

tha

t

ty

pe

of

flo

w

in

wh

ich

the

de

nsi

ty

of

theflu

id

ch

an

ge

s

fro

m

po

int

to

po

int

.

(e

g)

Fl

ow

of

ga

sses

thr

ou

gh

ori

fic

e

no

zzl


68/122

e

an

d

ga

s

tur

bi

ne.

26

)

De

fin

e

in

co

m

pr

essibl

e

flo

w?

In

co

m

pr

ess

ibl

e

flo

w

is

tha

t

ty

pe

of

flo

win

wh

ich

the

de

nsi

ty

is

co


69/122

nst

ant

for

the

flu

id

flo

w.

(e

g)

Su

bs

on

ic

aer

od

yn

am

ics.

27

)

De

fin

e

ro

tat

io

nal

flo

w?

Ro

tat

io

nal

flo

w

istha

t

ty

pe

of

flo

w

in

wh


70/122

ich

in

wh

ich

the

flu

id

pa

rti

cle

flo

wi

ng

alo

ng

str

ea

ml

ines,

als

o

rot

ate

ab

ou

t

the

ir

ow

n

axi

s.

28

)

De

fin

e

irr

ot

ati

on

al

flo

w?

It

is

tha


71/122

t

ty

pe

of

flo

w

in

wh

ich

the

flu

id

pa

rti

cle

wh

ile

flo

wing

alo

ng

str

ea

ml

ine

s,d

o

no

t

rot

ate

ab

ou

t

the

ir

ow

n

axis.

29

)

De

fin

e

on

e


72/122

di

m

en

sio

na

l

flo

w?On

e

di

me

nti

on

al

flo

w

is

tha

t

ty

pe

of

flo

w

in

wh

ich

theflo

w

pa

ra

me

ter

su

ch

aa

s

vel

oci

ty

is

a

fu

nct

io

n


73/122

of

ti

me

an

d

on

e

sp

ac

e

co

-

or

di

nat

e

on

ly,

say

X.

U

=F

(x)

,V

=0

,w

=0

.

30

)

De

fin

e

tw

o

di

m

en

sio

na

l

flo

w?


74/122

It

is

tha

t

ty

pe

of

flo

w

in

wh

ich

the

vel

oci

ty

is

afu

nct

io

n

of

ti

me

an

d

tw

o

rec

tan

gu

lar

sp

ac

e

sa

y

Xan

d

Y.

u=

F1(X

,Y

),


75/122

V

=F

(X

,Y

)

an

d

w

=0

.

231

)

W

ha

t

is

th

re

e

di

m

en

tio

na

l

flo

w?A

thr

ee

di

me

nti

on

al

flo

w

istha

t

ty

pe

of

flo

w

in


76/122

wh

ich

the

vel

oci

ty

is

a

fu

nct

io

n

of

ti

me

an

d

thr

eem

ut

ual

ly

pe

rp

en

dic

ula

r

dir

ect

io

ns.

U

=F

1(X

,Y,

X)

,v=F

2(X

,Y,

Z),

w

=F

(X


77/122

,Y,

Z).

U,

v,

w

are

vel

oci

ty

co

m

po

ne

nts

in

X,

Y,

Z

direct

io

n

res

pe

ctl

y.

332

)

W

ha

t

is

tot

al

ac

cel

er

ation

of

th

re

e

di

m

en


78/122

sio

na

l

flu

id

flo

w?

Ifa,ax,aare

the

tot

al

ac

cel

era

tio

n

in

x,y

,z

dir

ect

io

ns.

Th

enayz=d

u/

dt

=u

.

(u/

x

)

+v.

(u/

y)

+w

.

(


79/122

u/

z)

+u/

t.ax=d

v/

dt

=u

.

(v/

x)

+v.

(

v/y)

+w

.

(v/

z)

+v/

t.ay=d

w/

dt

=u

.

(w/

x

)+v.

(w/

y)

+w

.

(


80/122

w/

z)

+w/

tz33

)

De

fin

e

loc

al

ac

cel

er

ation

?

It

is

de

fin

ed

as

the

rat

e

of

inc

rea

ce

of

vel

oci

ty

wi

thres

pe

ct

to

ti

me

at

a


81/122

giv

en

po

int

in

a

flo

w

fie

ld.

34

)

De

fin

e

co

nv

ect

ive

ac

cel

er

ati

on

?

It

is

de

fin

ed

as

the

rat

e

of

ch

an

ge

ofvel

oci

ty

du

e

to

the

ch


82/122

an

ge

of

po

siti

on

of

flu

id

pa

rti

cle

in

a

flu

id

flo

w.

35)

De

fin

e

vel

oci

ty

po

ye

ntial

fu

nc

tio

n?

It

is

de

fin

edas

a

sc

ala

r

fu

nct

io


83/122

n

of

sp

ac

e

an

d

ti

me

su

ch

tha

t

its

ne

gat

ive

de

rivati

ve

wi

th

res

pe

ct

to

an

y

dir

ect

io

n

giv

es

the

flu

id

vel

ocity

in

tha

t

dir

ect

io

n.I


84/122

t is

de

no

ted

by

F.U

=

-F/x,v

=-

F/y,w

=-

F

/z.

U,

v,

w

are

the

vel

oci

ty

in

x,y,z

dir

ect

io

n.

36

)

M

en

tion

th

e

pr

op

ert

ies


85/122

of

po

te

nti

al

fu

nc

tion?

1.I

f

vel

oci

ty

po

ten

tia

lexi

sts

,T

he

flo

w

sh

ou

ld

be

irrota

tio

nal

.

2.I

f

vel

oci

ty

po

ten

tia

l

sat

isf

ies

the

lap

lac


86/122

e

eq

uat

io

n,I

t

re

pr

es

ent

s

the

po

ssi

ble

ste

ad

y

inco

m

pr

ess

ibl

e

irr

ota

tio

nal

flo

w.

37

)

De

fin

e

str

ea

m

fu

nc

tio

n

It

is

de

fin


87/122

ed

as

the

sc

ala

r

fu

nct

io

n

of

sp

ac

e

an

d

ti

me

,su

ch

tha

t

its

pa

rti

al

de

riv

ati

ve

wi

th

res

pe

ct

to

an

y

direct

io

n

giv

es

the

vel

oci


88/122

ty

co

m

po

ne

nt

at

rig

ht

an

gle

s

to

tha

t

dir

ect

io

n.It is

de

no

ted

by

38

)

M

en

tion

th

e

pr

op

ert

ies

of

str

eam

fu

nc

tio

n?

1.I

f

str


89/122

ea

m

fu

nct

io

n

exi

sts

,it

n

is

a

po

ssi

ble

ca

se

of

fluid

flo

w

wh

ich

ma

y

be

rot

ati

on

al.

2.I

f

str

ea

m

fu

nct

io

nsat

isf

ies

lap

lac

e

eq

uat


90/122

io

n,

It

is

a

po

ssi

ble

ca

se

of

an

irr

ota

tio

nal

flo

w.

39)

W

ha

t

is

eq

ui

po

te

ntial

lin

e?

A

lin

e

alo

ng

wh

ichthe

vel

oci

ty

po

ten

tia

l


91/122

Fis

co

nst

ant

is

cal

led

eq

ui

po

ten

tia

l

lin

e.


92/122

40

)

Gi

ve

th

e

relati

on

be

tw

ee

n

str

ea

m

fu

nc

tio

n

an

d

vel

oci

ty

po

te

nti

al

fu

nc

tio

n?

u=

-

F/x

an

d

v=

-

F/y


93/122

u=

-

/yan

d

v=

-

/xu=

-

F/x=

-

/yan

d

v=

-

F/y=-

/xHe

nc

e

F/x=

/yF/y=-/x


94/122

1.

W

ha

t

is

flo

w

net?

A

gri

d

ob

tai

ne

d

by

dr

aw

in

g

a

se

rie

s

of

eq

ui

p

m

en

t

lin

es

an

d

stea

m

lin

es

is

cal

le

d


95/122

a

flo

w

ne

t.

Th

e

flow

ne

t

is

an

im

po

rt

an

t

to

ol

is

an

aly

sis

tw

o

di

m

en

sio

na

l.

irr

ot

ati

on

alflo

w

pr

ob

le

ms

.

2.


96/122

W

ha

t

ar

e

th

e

type

s

of

m

oti

on

of

flu

id

pa

rti

cle

?

i.Li

ne

ar

tr

an

sla

tio

n

or

pu

re

tr

an

sla

tion.

ii.Li

ne

ar

De

fo

r


97/122

m

ati

on

.

iii.

A

ng

ular

De

fo

r

m

ati

on

iv.Ro

tat

io

n.

3.

W

ha

t

ar

e

lin

ea

r

tr

an

sla

tio

n?

It

is

defin

ed

as

th

e

m

ov

e


98/122

m

en

t

of

a

flu

id

elem

en

t

in

su

ch

a

wa

y

th

at

it

m

ov

es

bo

dil

y

fr

o

m

on

e

po

sit

io

n

to

repr

es

en

ts

in

ne

w

po


99/122

sit

io

n

by

a

b

&

cd

ar

e

pa

ral

lel.

4.

W

ha

t

is

lin

ea

r

de

fo

r

m

ati

on

?

It

is

de

fin

ed

as

th

ede

fo

r

m

ati

on

of

a


100/122

flu

id

ele

m

en

t

in

linea

r

di

re

cti

on

w

he

n

th

e

ele

m

en

t

m

ov

es

th

e

ax

es

of

th

e

ele

m

en

tin

th

e

de

fo

r

m

ati


101/122

on

po

sit

io

n

an

d

unde

fo

r

m

ati

on

po

sit

io

n

ar

e

pa

ral

lel

bu

t

th

eir

le

ng

th

s

ch

an

ge

s.

5.

Defin

e

an

gu

lar

de

fo

r


102/122

m

ati

on

?

It

is

de

fined

as

th

e

av

er

ag

e

ch

an

ge

in

th

e

an

gle

co

nt

ai

ne

d

by

tw

o

ad

ja

ce

nt

sides.

Le

t s

&

s

is

th

e


103/122

ch

an

ge

in

an

gle

be

twee

n

tw

o

ad

ja

ce

nt

sid

es

of

a

flu

id

ele

m

en

t .

Th

e

an

gu

lar

de

fo

r

m

ati

on=1

/2

*(

S1+S


104/122

).

6.

De

fin

e

rotat

io

n

of

flu

id

ele

m

en

t?

It

is

de

fin

ed

as

th

e

m

ov

e

m

en

t

of

a

flu

id

elem

en

t

in

su

ch

a

wa


105/122

y

th

at

bo

th

of

2rotat

e

in

sa

m

e

di

re

cti

on

. It

is

eq

ua

l

to

1/

2(

v/

x-u

/y)

for

a

tw

o___


106/122

_dim

en

sio

na

l

ele

men

t

x,

y

pl

an

e.

=1

/2(

u/x

-u/y)

z=1/2(

w/y-


107/122

v/z)

x=1

/2(

u/z-w/x)

7.

De

fine

vo

rte

x

flo

w

m

en

tio

nits

ty

pe

s?

Vo

rte

x

flo


108/122

w

is

de

fin

ed

as

th

eflo

w

of

a

flu

id

al

on

g

a

cu

rv

ed

pa

th

or

th

e

flo

w

Of

a

ro

tat

in

g

m

as

sof

flu

id

is

kn

ow

n

as


109/122

vo

te

x

flo

w.

i.Fo

rced

vo

rte

x

flo

w.

ii.Fr

ee

vo

rte

x

flo

w.

8.

De

fin

e

fre

e

vo

rte

x

flo

w?

W

he

n

noex

ter

na

l

to

rq

ue

is


110/122

re

qu

ire

d

to

ro

tat

eth

e

flu

id

m

as

s

th

at

ty

pe

of

flo

w

Is

cal

le

d

fre

e

vo

rte

x

flo

w.

9.

De

fin

efor

ce

d

vo

rte

x

flo

w?


111/122

Fo

rc

ed

vo

rte

x

flo

wis

de

fin

ed

as

th

at

ty

pe

of

vo

rte

x

flo

w

in

w

hi

ch

so

m

e

ex

ter

na

To

rq

ue

isre

qu

ire

d

to

ro

tat

e


112/122

th

e

flu

id

m

as

s.

The

flu

id

m

as

s

in

th

e

ty

pe

of

flo

w

ro

tat

es

at

co

ns

ta

nt

A

ng

ul

ar

vel

oci

tyw

.T

he

ta

ng

en

tia

l


113/122

vel

oci

ty

of

an

y

flu

idpa

rti

cle

is

giv

en

by

v=

co

sr.

y


114/122

10.Givetheequationofmotionforvortexflow?PressureactingPSAonthefaceAB.Pressureforce(P+p/rr)SAonthefacecd.centrifugalforcemv2/ractinginthedirectionaway.FromcenterONowthemassoftheelement=massdensity*volume=*A*rCentrifugalforce=*A*r*v2/rEqualtheforcesintheradialdirectionweget(P+p/rr)A-p


115/122

A=pArv2/rp/rrA=pArv2/rCancelling A,ronbothsideswegetp/r=pv2/r11.Whataretheforcespresentinthefluidflow?a)Gravityforce(F)b)Pressureforce(Fg)c)Forceduetoviscosity(Fp)d)Forceduetoturbulence(Fv)e)Forceduetocompressibility(Ft)12.WhataretheassumptionsmadeinthedeviationofBernoulliseqn?iThefluidisidealie,vis


116/122

cosityiszeroiiTheflowissteady.iiiTheflowisincompressible.ivTheflowisirrotational.13.StateBernoullistheorem?Itstatesthatinasteady,idealflowofanincompressiblefluid,thetotalenergyatanypointofthefluidisconstant.Itiswrittenas,P/w+v2o/2g+z=constant.14.WhatisVenturimeter?Mentionitsparts?Venturimeterisadeviceusedformeasuringtherateofflowofafluidflowingthroughapipe.Parts: iAsh


117/122

ortconvergantpart.iiThroat.iiiDivergantpart.]15.WhatisOrificemeter?


118/122

OrificemeterisadeviceusedformeasuringtherateofflowoffluidthroughaPipe.ItisacheaperdeviceascomparedtoVenturimeter.ItworksonthesameprincipleofVenturimeter.16.Whatispitottube?Pitottubeisadeviceusedform

easuringthevelocityofflowatanypointinapipeOrachannel.17.Whatismomentumeq

uationItisbasedonthelawofconservationofmomentumoronthemomentu


119/122

mprincipleItstatesthat,thenetforceactingonafluidmassisequaltothechangeinmomentumofflowperunittimeinthatdirection.Expression:TheforceactingonthefluidmassmisgivenbyF=m*aWhereF=forcem=massoffluid

a=acc18.Whatisimpulsemomentumequation?F=m*aButa=dv/dtF=m*dv/dt=d/dt(mv)F=d(mv)/dtF.dt=d(mv)Thisisimplsemomentumequation.Statement:


120/122

ItstatesthattheimpulseofaforceFactingonafluidmassminafhortintervaloftimedtisequaltothechangeofmomentumd(mv)inthedirectionofforce.19.Statemomentumofmomentumequation?Itstatesthattheresultingtorq

ueactingonarotatingfluidisequaltotherateofchangeofmomentofmomentum.20

.GivetheexpressionforBernoullisequationofrealfluid?P11 2/g+V/2g+Z1=P


121/122

222/g+V/2g+Z2+hWhere/g=Pressureheadatsection1VP11 2/2g=Velocityheadatsection1reheadatsection2V2 2/2g=Velocityheadatsection

2Z=datumheadatsection2h2L2=lossofenergybetweensections1&2


122/122

Documents

Me1202 - Fluid Mechanics Machineries