Flow over bicycle

This program is for the calculation of drag force experienced by a cyclist.

Let the density of air be 1.2 kgm^-3 and the frontal area be 0.4 m^2. The velocity of the cyclist varies from 0 to 20 ms^-1 . The coefficient of drag vaires as 0.2, 0.5 and 0.8 depending upon the position of the cyclist. If the shape is streamlined the coefficient of drag is 0.2 and if he is upright it is 0.8

The code for achieving this calculation is done using matlab as follows:

%drag force experienced by a cyclist
clear all
close all
clc
%inputs
%density of air kgm^-3
rho=1.2;
%frontal area m^2
a=0.4;
%coeffiecent of drag 
cd=[0.2 0.5 0.8];
%velocity of cyclist ms^-1
v=[0:20];
for i=1:length(cd)
    CD=cd(i);
    drag_force=0.5*a*rho*CD*v.^2;
    figure(i)
    plot(v,drag_force)
    axis([0 20 0 80])
    xlabel(\'velocity\');
    ylabel(\'drag force\');
end
%for simplicity I am plotting the graph of coeff.of drag vs drag force only
%for velocities of 5,10 and 20 ms^-1
velocity=[5 10 20];
for j=1:length(velocity)
    V=velocity(j);
    Drag_force=0.5*a*rho*cd.*V^2;
    figure(j+3)%since already 3 figures are computed in previous for
    plot(cd,Drag_force)
    xlabel(\'coeff. of drag\')
    ylabel(\'drag force\')
    axis([0 1 0 80])
end
%for comparison of plots method of copying and pasting the line plot is
%used

Drag force vs Velocity for cd=0.2

Drag force vs velocity for cd=0.5

Drag forcevs velocity for cd=0.8

comparison of drag force vs velocity for various cd: (as cd increases drag force increases)

Drag Force vs Drag coeff. for v=5 ms^-1

Drag force vs Drag coeff. for v= 10 ms^-1

Drag force vs Drag coeff. for v= 20 ms^-1

Comparion of Drag force vs Drag coeff. for different velocites: (as velocities increases drag force increases largely since drag force proportional to velocity^2 )