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Hydraulic & Fluid Mechanics

Hydraulic & Fluid Mechanics

Density/Mass density: mass/unit volume at standard temp and pressure.
rho =M/V
unit: kg /me
Weight density/specific weight: weight /unit volume  at standard temperature and pressure.
w=rho x g
unit : N/me
Specific volume: volume/unit mass of liquid 
v=V/m
unit : m3/ kg
Specific gravity: it is defined as specific weight of liquid to specific weight of pure water at 4 degree C
it has no unit
Viscosity: it offers resistance to movement of one layer of liquid to another layer 
Compressibility: properly change in volume to change in pressure.
it is reciprocal of bulk modulus of elasticity.
Surface tension: property of liquid which enables to resist tensile stress denoted by sigmaunit  : N/m
Capalary: phenomena of rise /fall of surface in small tube held in liquid relatives.
Pressure of liquid: When liquid contained in vessel it exerts at all points on side & bottom of vessel
force per unit volume area called intensity by pressure 
unit: N/m2
Pascal law : intensity of pressure  at any point in liquid at rest is same in all directions

Hydraulic & Fluid Mechanics

Measurement of pressure:
  • simple pizometer &u tube nanometer
  • differential nanometer 
Menometer used to measure 
  • High pressure of liquid 
  • vacume pressure 
  • pressure in pipe 
Archimedes principles: when body is immersed wholly or partially  in liquid it is lifted up by force equal to weight of liquid displace by body

Hydraulic & Fluid Mechanics

Tendancy of liquid to uplift an immersed body beacause of upward thrust of liquid is known as buoyancy.
Point where buoyancy force supposed that is known as centre of buoyancy
bouyancy of force is more= float
bouyancy of force is less =sink down
Meta centre : is a point about which a floating body start oscillating when given smaller angular displacement .
Meta centric height : distance between centre gravity of floating body and metacentre 
Uniform flow: all section same velocity 
Non uniform flow: different sections have different velocity 
stream line : each point have define path  and these path does not cross each other.

  • Bernaulli 's Equation 
  • Z1+(v1/2g)+(p1/W) = Z2+(v2/2g)+(p2/W)
Assumption 
  • fluid is non viscous 
  • fluid is homogeneous and incomressible 
  • the flow is continuous steady and along streamline
  • velocity flow is uniform over section 
Pitot tube measures velocity of flow
very small dia. is ven contracta 
spill way ofe wear is used 
1poise = 0.1 N-s/m2
1stroke = 1 cm2/s

  • Hydraulic & Fluid Mechanics

  •  law of viscosity 

  • fluid with no viscosity is ideal fluid 
  • fluid with viscosity is real fluid 
  • viscosity does not change rate of deformation  is newtonian fluid
  • viscosity change with deformation is non newtonian fluid 
raynold 's No. less than 2000 is laminar flow
raynold 's No. is greater than 2800 is turbulent  flow

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