Fluid mechanics and hydraulic machinery definitions

FLUID MECHANICS AND HYDRAULIC MACHINERY DEFINITION:

Adhesion :

             The attraction between the molecules of a liquid and molecules of a solid boundary surface in contact with liquid.

Cohesion :

           The  inter-molecular attraction between molecules of the same liquid.

TURBINE:
        A turbine is defined as the hydromachine which convert the hydraulic energy to mechanical energy and then this mechanical energy is converted into electrical energy when it is connected to generator.
Different types of turbine are:
PELTON turbine
high head ,impulse turbine and axial flow.

KAPLAN TURBINE
medium head ,reaction turbine.
FRANCIS TURBINE
low head ,high discharge reaction turbine.

Hydraulic Machine:
Turbine,Pump,Compressor etc.

Capillarity :

          It is defined as the phenomenon of rise (or)fall of aliquid surface in a small tube relative to the adjacent general level of liquid.when the tube held verticallyin the liquid capillarity rise(or)fall is due to the combined effect of adhesion and cohesion.

Vortex :

         In fluid dynamics a vortex is aregion in afluid in which the flow revoles around the axis line,which may be straight (or) curved example : smoke rays ,wind revolving around dust  

Buoyancy principle:

       When a body is immersed in a liquid, it is lifted up by a force equal to weight of liquid displaced by the body. The tendency of liquid to lift up an immersed body is buoyancy. The upward thrust of liquid to lift up the body is called buoyancy force.
Bernoulli's Equation:
P/γ +V²/2g +Z = Constant

Where, P = pressure,

V = velocity,

Z = Datumn Head

Devices for fluid:

Venturimeter :     It measures discharge of fluid.

Piezometer    :    It measure pressure rate of fluid.
Notches        :    It measures discharge of fluid.
Orifice meter: It measures discharge of fluid.
Pitot tube     : It measures velocity of fluid.

Fluid discharge/Fluid flow:
Quantity of fluid flowing per second.

(through a section of pipe/ through a section of channel)

Q=AV

where, V= velocity of fluid,A= cross-sectional area of pipe/channel
Note: 1m³ = 1000 L1 cusec = 1 ft³/sec1 ft = 0.3048 m

Hydraulic Machine:
Turbine,Pump,Compressor etc.

Draft tube:
           It attaches with reaction turbine . Its function is to reduce energy loss from reaction turbine & it also reduce pressure at outlet which is must blow the atmospheric pressure.

Specific Weight:
Weight per unit volume of the fluid.

Specific Volume:
Volume per unit mass of the fluid.

Specific Gravity:
            It is the ratio of specific weight of required substance to specific weight of pure water at 4 degree centigrade temperature.

Specific heat:
            The amount of heat required to increase 1 unit temperature of 1 unit mass.
Viscosity:
Dynamic Viscosity:
The amount of resistance of one layer of fluid over other layer of fluid.Kinematic Viscosity:
It is the ratio of dynamic viscosity to density.

Surface tension :

          It is caused by the force of cohesion at the free surface (or) surface energy per unit volume of the liquid.

Archimedes principle :

        It is the physical law of the buoyancy discoved by the ancient greek mathematician and inventor Archimedes stating that any body completely(or) partially submerged in a fluid (gas(or) liquid) at rest is acted upon by an upward as buoyant force the magnitude of which is equal to the weight of the fluid.