1. ATMIYA institute of technology
&
science

2. NAME :- BHARGAV SHOLANKI - 150030106106
BHAUTIK VACHHANI - 150030106114
HEMAL VADHER - 150030106115
BRANCH:- CIVIL ENGNEERING
DIVISON:- GY-3
SUBJECT:- FLUID MECHANICS

3. FLUID
&
THIER PROPERTIES

4. INTRODUCTION
Definition of Fluid :- Allmattercanbedividedinto2majorclasses
1)Solid
2)Fluids
Thedifferencebetweenasolidandfluidcanbedefinedby
1)Thestress-strainrelationship
2)Theelasticity

5. Solid
requiresexternalforcestocauseittodeform.
Fluid
willdeformwithouttheapplicationofexternal
forces.
willtakeontheshapeofthecontainerinwhich
theyareheld.
-Ex.water,oil,gas etc.

6. Hydrostatics: that studies the mechanics of fluids at absolute and
relative rest.
Kinematics: deals with translation, rotation and
deformation of fluid without considering the force and
energy causing such a motion
.
Dynamics: that prescribes the relation between velocities and
acceleration and the forces which are exerted by or upon the
moving fluids.
Fluid machanics

7. Properties of Fluids
Density is the mass of the fluid per unit volume
Density ()
 = Density of fluid, kg/m3
M = Mass of fluid, kg
V = Unit volume, m3
 = M
V

8. The specific weight is the weight of the fluid per unit
volume
 = Specific weight, N/m3
W = Weight of fluid, N (W=mg)
V = Unit volume, m3
 = W
V
The specific weight of water at 40C = 9.81 kN/m3
Specific Weight/Unit Weight ()

9. The specific gravity is the ratio of the density or
specific weight of the fluid to the density or specific
weight of water, at a temperature of 4oC
Specific Gravity/Relative Gravity (S)
S =
w
 =
w
 Dimensionless

10. Viscosity
It is the property of the fluid by virue of
which it offers resistance to shear or angular
deformation.
Mollases,tar, glycerine are highly viscous fluids.
Water,air,petrol have very small viscosity and are called
thin fluids.

11. Newton’s Law of Viscosity
=  (du/dy)
Where, du/dy =velocity gradient
= coefficient of viscosity.
It’s states that the shear stress(  ) on a fliud
element layer is directly proportional to the rate of shear
strian.

12. Classifiction of fluid
The fluid may be classified into the five types:-
1) Ideal fluid
2) Real fluid
3) Newtonian fluid
4) Non – newtonian fluid
5) Ideal plastic fluid

13.  Ideal fluid isasubstancethatisunabletoresistinternal
shearandtensileforces.
Real fluid :- A fluid whichiscompressible,hasvisocityand
surfacetension ,isknown asrealfluid
Newtonian fluid:- Arealfluidinwhichtheshearstressisdirectly
totherateofshearstrain,isknownasnewtonianfluid.
Non-newtonian fluid:-Arealfluid,inwhichtheshearstressisno
proportionaltotherateofshearstrain,isknownasnon-newtonian
fluid.
 Ideal plastic fluid:- afluidinwhichshearstressismorethan theyield value
andshearstressisproportionaltotherate ofshearstrainisknownasanidea
plasticfluid.

14. surface tension
 Tensileforceactingonthefreesurfaceof
aliquidperunitlengthiscalledsurfacetension
 s.IunitofsurfacetensionisN/MorN/MM itis
denotedbysigma (σ)

15.  Surfacetensionisacontractivetendencyofthesurface of
a fluid that allows it to resist an external force. Surface
tension is an important property that markebly
influencestheecosystems.

17. CAPILLARY
Capillaryactionistheabilityofafluidtoflowinnarrow
spaceswithouttheassistanceof,andinoppositionto,external
forceslikegravity.

19. THANK YOU