Chapter 15: Uniform Flows in Open Channels

Example 15.1, Page 516

In [1]:
from __future__ import division
import math


 #Initializing  the  variables
B  =4;
D  =  1.2;
C  =  7.6;
n  =  0.025;
s  =  1/1800;

 #Calculations
W  =  B  +  2*1.5*D;
A  =  D*(B+C)/2;                                                #  Area  of  parallelogram  formed
P  =  B  +2*1.2*(D**2+(1.5)**2)**0.5;
m  =A/P;
i=s;
C  =  (23+0.00155/i+1/n)/(1+(23+0.00155/i)*n/(m)**0.5);         #  By  Kutter  formula
Q1  =  C*A*(m*i)**0.5;
Q2  =  A*(1/n)*m**(2/3)*(i)**0.5;

print "Q using Chezy formula with C determined from the Kutter formula (m^3/s) :",round(Q1,2)
print "Q using the Manning formula                                     (m^3/s) :",round(Q2,2)

Q using Chezy formula with C determined from the Kutter formula (m^3/s) : 5.65
Q using the Manning formula                                     (m^3/s) : 5.69

Example 15.2, Page 518

In [1]:
from __future__ import division
import math

 #Initializing  the  variables
Q  =  0.5;
C  =  80;
i  =  1/2000;

 #Calculations

# A = D**2+(3/4)*D**2 = (7/4)*D**2
D = ((4/7)*(Q/C)*(2/i)**0.5)**(2/5)

#Result
print "Optimum depth = Optimum Width (in metres):",round(D,3)

Optimum depth = Optimum Width (in metres): 0.552