MECHANICAL ENGINEERING SHORT NOTES [ FLUID MECHANICS ] ~ MECHANICAL ENGINEERING SHORT NOTES

MECHANICAL ENGINEERING SHORT NOTES

Hello And Welcome!

Mechnotes presents high quality handwritten short notes for various examinations of mechanical engineering which includes GATE, SSC JE, PSU, and ESE.

Short notes are the ultimate weapons during the whole preparation. Many students usually do not come up with short notes and they suffer badly in the last few days or months before the examination. Short notes must be clean and error-free so that you can make the best use of that in limited time. It will help you in quick revision and boost your confidence. Here you will get mechanical engineering short notes pdf with high-quality content.

Subject - Fluid Mechanics

Topic Covered -

Fluid properties
Pressure and its measurement
Hydrostatic forces and Buoyancy
Kinematics of fluid
Dynamics of fluid
Laminar flow
Turbulent flow
Flow through pipes
Boundary layer theory

FLUID PROPERTIES

A fluid is a substance that deforms continuously in the presence of shear stress and it never gains original position. Some basic properties of the fluid are density, specific weight, specific volume, and specific gravity.

Viscosity- It is the property of the fluid which offers resistance to shear deformation.

In fluid, the rate of shear deformation is more important then deformation.

Kinematic Viscosity- It is the ratio between dynamic viscosity and density of the fluid.

The viscosity of liquid decreases with an increase in temperature and the viscosity of gases increases with an increase in temperature.

Newton law of viscosity- According to it, shear stress in fluid is directly proportional to shear strain.

Fluid obeys Newton law of viscosity known as Newtonian fluids and fluid which doesn't obey Newton law of viscosity known as Non-Newtonian fluids.

No slip phenomena happen because of the viscous effect of fluid at the liquid-solid interface. Boundary layer formation is the result of no slip phenomenon.

Bulk Modulus- It is defined as the ratio of compressive stress to volumetric strain.

Surface tension- Defined as a tensile force acting on the surface of the liquid in contact with gas or liquid medium such that the contact surface behaves like a membrane in tension.

The magnitude of force per unit length of the surface is equal to surface energy per unit area.

Capillarity- Defined as rise or fall of a liquid surface inside a small diameter tube held vertically in liquid.

PRESSURE AND ITS MEASUREMENT

Pascal law- The intensity of pressure at a point is equal in all directions in a static fluid. When the fluid is at rest then shear stress is zero.

Hydrostatic law- The rate of increase of pressure in a downward direction is equal to the specific weight of the fluid at that point.

Absolute pressure- Pressure measured from reference as absolute vacuum pressure.

Gauge pressure- Pressure measured from reference as atmospheric pressure.

Manometer- Pressure is measured by balancing the column of fluid by the same or another column.

Mechanical Gauge- Pressure is measured by balancing fluid column by spring or dead weight.

Center of Pressure- Point of application of resultant hydrostatic force.

Buoyancy- For buoyancy, the net horizontal force exerted on a body should be zero. The net vertical upward hydrostatic force exerted by fluid known as buoyant force. The magnitude of buoyant force is equal to the weight of the liquid displaced. Its point of application is the center of gravity of the displaced fluid known as center of buoyancy.

KINEMATICS OF FLUID

Steady flow- flow in which fluid characteristic properties like velocity, density do not change with time.

Unsteady flow- flow in which fluid characteristic properties like velocity, density changes with time.

Uniform flow- type of flow in which velocity at any given time does not change with respect to space.

Nonuniform flow- type of flow in which velocity at any given time changes with respect to space.

Compressible flow- type of flow in which density changes from point to point.

Incompressible flow- type of flow in which density does not change from point to point.

Laminar flow- type of flow in which particle moves in a well-defined path or streamline path.

Turbulent flow- type of flow in which fluid particles move in a zig-zag manner. In this mixing of particles takes place.

Rotational flow- type of flow in which fluid particle rotates about their own axis while moving.

Irrotational flow- type of flow in which fluid particles do not rotate about their own axis while moving.

Continuity equation- It is based on the principle of conservation of mass.

Vortex flow- the flow of fluid along a curved path.

DYNAMICS OF FLUID

Bernoulli equation is derived from the Euler equation and it is based on the principle of conservation of energy.

Assumption in Bernoulli equation-

Inviscid flow
Incompressible flow
Steady flow
Irrotational flow

Practical application of Bernoulli equation-

Venturimeter- Measure the rate of flow of fluid.
Orifice Meter- Measures rate of flow of fluid.
Pitot Tube- Measures the velocity of flow in the fluid.

VISCOUS FLOW

If the Reynolds number is less then 2000 on a pipe then it is called laminar flow and if the Reynolds number is more than 4000 then it is called turbulent flow.

Navier stokes equation is the fundamental equation for viscous flow.

Viscous flow in the pipe has the parabolic distribution of velocity and the linear distribution of shear stress.

In laminar flow, loss of pressure head is directly proportional to mean velocity of the fluid. While in turbulent flow it is approximately proportional to the square of it.

Fluid Mechanics is one of the important subjects in terms of marks in different examinations. By putting some extra effort it is easily possible to solve all the problems related to it.

All important concepts and formulas are also present there. It will help you in steady quick revision and save your precious time so that you can practice more problems related to Fluid Mechanics. Always refer to standard textbooks for doubt.

BUY NOW