1. BIRLA VISHVAKARMA MAHAVIDHYALAYA GUJARAT TECHNOLOGICAL UNIVERSITY DEPARTMENT OF CIVIL ENGINEERING B.V.M. Engg. College, V.V.Nagar B.E. SECOND LEVEL - THIRD SEM SUBJECT: FLUID MECHANICS (2130602) PREPAIRED BY: GUIDED BY: Name Enrollment No. Prof. H. V. PATEL Haresh Shiyara 130070106116 Civil Engg. Dept., Himanshu Solanki 130070106117 BVM Engg. College, Sonagara Divya 130070106118 Vallabh Vidyanagar. Jay Soni 130070106119 Tank Nirali 130070106120 Thummar Kishan 130070106121

2. Properties of Fluids Definition of fluid Properties of fluids Calculations

3. What is hydrostatics? Definition of Fluid All matter can be divided into 2 major classes 1) Solid 2) Fluids The difference between a solid and fluid can be defined by 1) The stress-strain relationship 2) The elasticity

4. What is hydrostatics? The Stress-Strain Relationship Solid requires external forces to cause it to deform. Fluid will deform without the application of external forces. will take on the shape of the container in which they are held. -Ex. water, oil, gas etc.

5. What is hydrostatics? The Elasticity Relationship Solid -When external forces stress and deform solids, the solid will regain their original shape when these external forces are removed [Elasticity]. Fluid -Fluid will continue to change shape in time even after the removal of the external forces causing the deformation.

6. What is hydrostatics? Ideal Fluid Ideal fluid is a substance that is unable to resist internal shear and tensile forces.

7. What is hydrostatics? Liquid and Gases Fluids can be classified into 2 forms of matter 1) Liquids 2) Gases The difference between a liquid and gas can be defined by 1) The compressibility 2) The continuity

8. What is hydrostatics? Compressibility :to compress something into a small space. Liquids Liquids are considered to be incompressible. Liquids only change in volume even when subjected to very high pressure. Gases Gases are very compressible. Their volume can increase/decrease when subjected to slight variation in pressure.

9. What is hydrostatics? Continuity : It is the state of being continuous. Liquids When a liquid is held in a container, its entire mass will arrange itself so as to be in contact with the bottom and the sides of that container, and a well-defined surface of the liquid will form. Gases A gas held in a closed container will not form a well-defined surface and will tend to fill the entire container.

10. What is hydrostatics? Properties of Fluids Density is the mass of the fluid per unit volume Density (  )  = Density of fluid, kg/m 3 M = Mass of fluid, kg V= Unit volume, m 3  = M V The density of water at 4 0 C = 1,000 kg/m 3

11. What is hydrostatics? Properties of Fluids The specific weight is the weight of the fluid per unit volume  = Specific weight, N/m 3 W = Weight of fluid, N (W=mg) V= Unit volume, m 3  = W V The specific weight of water at 4 0 C = 9.81 kN/m 3 Specific Weight/Unit Weight (  )

12. What is hydrostatics? Properties of Fluids 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 4 o C Specific Gravity/Relative Gravity (S) S = ww  = ww  Dimensionless

13. What is hydrostatics? Properties of Fluids Viscosity is the measure of a fluid’s resistance to internal shear stresses. Dynamic Viscosity (  )  = Dynamic viscosity, N.s/m 2 or Pa.s  = Internal shear stress, N (  =F/A) v= Velocity, m/s  =  h v

14. What is hydrostatics? Properties of Fluids Let -A = the horizontal area of each layer -h = the vertical distance between their centerlines -F = internal shear force A thin layer of fluid The top layer is acted upon by F The top layer will move with a velocity, v relative to the bottom layer

15. What is hydrostatics? Properties of Fluids Ideal Fluid : -is unable to resist F -the relative velocity would remain constant, even F is removed Real Fluid : -is able to resist F due to 1) internal molecular activity 2) friction between the layers

16. What is hydrostatics? Properties of Fluids  =  h v F =  vA h  = F/A  =  v h If h 0  =  v  h Instantaneous rate of deformation of fluid Newton’s Law of Viscosity

17. TYPES OF VISCOMETER :-  Laboratory viscometers for fluid U-tube Falling sphere  Falling Piston Viscometers  Falling Sphere Viscometers

18. U-TUBE MANOMETER Pressure measuring devices using liquid columns in vertical or inclined tubes are called manometers. One of the most common is the water filled u-tube manometer used to measure pressure difference in pitot or orifices located in the airflow in air handling or ventilation system. p d = γ h = ρ g h where p d = pressure γ = specific weight of the fluid in the tube (kN/m 3, lb/ft 3 ) ρ = density (kg/m 3, lb/ft 3 ) g = acceleration of gravity (9.81 m/s 2, 32.174 ft/s 2 ) h = liquid height (m, ft)

19. SURFACE TENSION Surface tension is a contractive tendency of the surface of a fluid that allows it to resist an external force. Surface tension is an important property that markebly influences the ecosystems.

20. Whenever a fluid is left to itself, the fluid tends to attend the minimum surface area possible. The reason behind this is that while a molecule inside the fluid is pulled in each and every direction by the adjacent molecules in the surface of the fluid, the case is different. the adhesive forces causes downward pull on the molecule due to cohesent. So the molecule on the surface tends to move down but it is repelled by the molecules below it.

21. FORMULA USED TO CALCULATE SURFACE TENSION :- Where, Where, γ = surface tension θ = contact angle ρ = density g = acceleration due to gravity r = radius of tube

22. The magnitude of repulsive forces per unit length is called surface tension or coefficient of surface tension. σ = F/L

23. APPLICATION OF SURFACE TENSION :-  A water strider can walk on water.  Some tent are made impermeable of the rain but they are not really impermeable, but if water is placed on it then the water doesn’t pass through the fine small pores of the tent cover. But as you touch the cover while water is on it, you break surface tension and water passes through.

25. CAPILLARY ACTION :- Capillary action is the ability of a fluid to flow in narrow spaces without the assistance of, and in opposition to, external forces like gravity.

26. A common apparatus used to demonstrate the first phenomenon is the capillary tube. When the lower end of a vertical glass tube is placed in a fluid, such as water a concave meniscus forms. Adhesion occurs between the fluid and the solid inner wall pulling the fluid column up until there is a sufficient mass of fluid for gravitational forces to overcome these intermolecular forces. The contact length between the top of the fluid column and the tube is proportional to the diameter of the tube, while the weight of the fluid column is proportional to the square of tube’s diameter. So, a narrow tube will draw a fluid column higher than a wider tube will.

27. APPLICATION OF CAPILLARY ACTION :- Capillary action is found in thermometer where fluid used in it automatically rises when comes in contact with higher temperature or falls down with lower ones. Capillary action can be performed to transfer fluid from one vessel to another on its own. Capillary action can be experienced in the half dipped cloth as well as on lantern.

28. References A textbook of FLUID MECHANICS AND HYDRAULIC MACHINES – Dr. R. K. Bansal HYDRAULICS AND FLUID MECHANICS INCLUDING HYDRAULIC MACHINES – Dr. P. N. Modi and Dr. S. M. Seth.

29. THANK YOU !!