Chapter 11: Boundary Layer

Example 11.1, Page 383

In [1]:
from __future__ import division
import math


 #Initializing  the  variables
rho  =  860;
v  =  10**-5;
Us  =  3;
b  =  1.25;
l  =  2;

 #Calculations
x  =  1;                                                                    #  At  x  =1  
Rex  =  Us*x/v;
ReL  =  Us*l/v  ;
mu  =    rho*v;
T0  =  0.332*mu*Us/x*Rex**0.5;
Cf  =  1.33*ReL**-0.5;
F  =  rho*Us**2*l*b*Cf  ;
print "shear stress                                (N/m^2) :" ,round(T0,1)
print "Total, double-sided resistance of the plate (N)     :",round(F,3)

shear stress                                (N/m^2) : 4.7
Total, double-sided resistance of the plate (N)     : 33.224

Example 11.2, Page 387

In [2]:
from __future__ import division
import math


 #Initializing  the  variables
Us  =  6;
b  =  3;
l  =  30;
rho  =  1000;
mu  =  10**-3;
T  =  20+273;                                                          #  Temperature  in  Kelvin

 #Calculations
 
ReL  =  rho*Us*l/mu;  
Cf  =  0.455*math.log10(ReL)**-2.58    ;

F  =  rho*Us**2*l*b*Cf  ;
Lt  =  10**5*mu/(rho*Us);                                    #  Assuming  transition  at  Rel  =  10**5

print "Drag Force (kN)       :", round(F/1000,2)
print "Transition length (m) :",round(Lt,4)

Drag Force (kN)       : 6.36
Transition length (m) : 0.0167