By Group 1
1
 Md.Ariful Islam--------10307044
 Nur-E-Alam Siddike---10307050
 Abu Bakar Siddique---10307076
 Mahadi Hasan Rubel---10307059
 Arfan Hossain ----------11170119
2
 Know the formula
 Describe the formula
 Application of formula
 Importants of formula
3
Major Losses
 losses due to friction
Minor Losses
 entrance and exit
 sudden change of cross sections
 valves and gates
 bends and elbows ect
4
5
When the water is flowing in a pipe, it
experiences some resistance to its motion,
whose effect is the velocity and ultimately
the head of water available. An empirical
formula for the loss of head due to friction
was derived by Henry Darcy
6
hf = Loss of head due to friction
L = Length of pipe
D= Diameter of the pipe
7
8
 Let,
l= length of the pipe
D= diameter of the pipe
v= Velocity of water in the pipe
f'= Frictional resistance per unit area at unit
velocity
Consider sections (1-1) and (2-2) of the pipe
Let,
p1= Intensity of pressure at section (1-1)
p2= Intensity of pressure at section (2-2)
9
10
 Chézy was born at Chalon-
sur-Marne, France, on
September 1, 1718, and
died on October 4, 1798.
He retired in 1790 under
conditions of extreme
poverty. It was not until
1797, a year before his
death, that the efforts of
one of his former
students, Baron Riche de
Prony, finally resulted in
Chézy's belated
appointment as director of
the Ecole des Ponts et
Chaussées.
11
Chezy Formula : Can be derived from basic
principles. It states that
12
 V is velocity
 R is hydraulic radius
 S is slope of the channel
 C is Chezy coefficient and is a function of
hydraulic radius and channel roughness
13
14
 Let,
l= length of the pipe
D= diameter of the pipe
v= Velocity of water in the pipe
f'= Frictional resistance per unit area at unit
velocity
Consider sections (1-1) and (2-2) of the pipe
Let,
p1= Intensity of pressure at section (1-1)
p2= Intensity of pressure at section (2-2)
15
16
Figure from Hornberger et al. (1998)
17
Figure from Hornberger et al. (1998)
Generalization of Darcy’s column
h/L = hydraulic
gradient
q = Q/A
Q is proportional
to h/L
18
Figure from Hornberger et al. (1998)
Linear flow paths
assumed in Darcy’s
law
True flow paths
Average linear velocity
v = Q/An= q/n
n = effective porosity
Specific discharge
q = Q/A
19
Inflow = Outflow
Recharge
Discharge
Steady State Water Balance Equation
Transient Water Balance Equation
Inflow = Outflow +/- Change in Storage
Outflow - Inflow = Change in Storage
20
 Power generation
 Mining
 Refrigeration
 Vehicles
 Water supply drainage system etc.
21
22

Darcy’s law & chezy’s law

  • 1.
  • 2.
     Md.Ariful Islam--------10307044 Nur-E-Alam Siddike---10307050  Abu Bakar Siddique---10307076  Mahadi Hasan Rubel---10307059  Arfan Hossain ----------11170119 2
  • 3.
     Know theformula  Describe the formula  Application of formula  Importants of formula 3
  • 4.
    Major Losses  lossesdue to friction Minor Losses  entrance and exit  sudden change of cross sections  valves and gates  bends and elbows ect 4
  • 5.
  • 6.
    When the wateris flowing in a pipe, it experiences some resistance to its motion, whose effect is the velocity and ultimately the head of water available. An empirical formula for the loss of head due to friction was derived by Henry Darcy 6
  • 7.
    hf = Lossof head due to friction L = Length of pipe D= Diameter of the pipe 7
  • 8.
  • 9.
     Let, l= lengthof the pipe D= diameter of the pipe v= Velocity of water in the pipe f'= Frictional resistance per unit area at unit velocity Consider sections (1-1) and (2-2) of the pipe Let, p1= Intensity of pressure at section (1-1) p2= Intensity of pressure at section (2-2) 9
  • 10.
  • 11.
     Chézy wasborn at Chalon- sur-Marne, France, on September 1, 1718, and died on October 4, 1798. He retired in 1790 under conditions of extreme poverty. It was not until 1797, a year before his death, that the efforts of one of his former students, Baron Riche de Prony, finally resulted in Chézy's belated appointment as director of the Ecole des Ponts et Chaussées. 11
  • 12.
    Chezy Formula :Can be derived from basic principles. It states that 12
  • 13.
     V isvelocity  R is hydraulic radius  S is slope of the channel  C is Chezy coefficient and is a function of hydraulic radius and channel roughness 13
  • 14.
  • 15.
     Let, l= lengthof the pipe D= diameter of the pipe v= Velocity of water in the pipe f'= Frictional resistance per unit area at unit velocity Consider sections (1-1) and (2-2) of the pipe Let, p1= Intensity of pressure at section (1-1) p2= Intensity of pressure at section (2-2) 15
  • 16.
  • 17.
    Figure from Hornbergeret al. (1998) 17
  • 18.
    Figure from Hornbergeret al. (1998) Generalization of Darcy’s column h/L = hydraulic gradient q = Q/A Q is proportional to h/L 18
  • 19.
    Figure from Hornbergeret al. (1998) Linear flow paths assumed in Darcy’s law True flow paths Average linear velocity v = Q/An= q/n n = effective porosity Specific discharge q = Q/A 19
  • 20.
    Inflow = Outflow Recharge Discharge SteadyState Water Balance Equation Transient Water Balance Equation Inflow = Outflow +/- Change in Storage Outflow - Inflow = Change in Storage 20
  • 21.
     Power generation Mining  Refrigeration  Vehicles  Water supply drainage system etc. 21
  • 22.