Drag Force estimation over a bicycle

AIM : Program in MATLAB to calculate drag force against a cyclist .

1) Program to plot velocity v/s drag force.

2) Program to plot drag coefficients v/s drag forces.

THEORY : Drag is the resistance attributed to an object, in this case its air resistance . It is a product of an objects drag cofficient (cd) , density of the fluid ( `rho`), square of its velocity ( v^2)and its size , critically its frontal area ( area ).

D = 1/2 * `rho`*v^2 * area * cd

source link :https://www.cyclingpowerlab.com/CyclingAerodynamics.aspx

1) velocity v/s drag force

%PROGRAM TO FIND THE DRAG FORCE OVER A BICYCLE ( VELOCITY V/S DRAG FORCE)
clear all
close all
clc

% INPUTS
cd = [1.15,1,0.88];       % Co-efficient of drag for different shapes
area = [0.632,0.40,0.32]; % Area in m^2
rho = 1.225;              % Density in kg/m^3
v = [25,35,45];           % Velocity in m/s
drag_forces = 0.5*rho.*v.^2.*area.*cd 

% GRAPH PLOTS
plot(v,drag_forces);
xlabel('Velocity');
ylabel('Drag forces');
grid on

OUTPUT 1:

GRAPH 1:

2)drag coefficients v/s drag forces

%PROGRAM TO FIND THE DRAG FORCE OVER A BICYCLE ( DRAG FORCE v/s DRAG COEEFICIENT)
clear all
close all
clc

% INPUTS
cd = [1.15,1,0.88,0.70];       % Co-efficient of drag for different cyclist's position shape on his cycle 
area = 0.32;              % Area =0.32 m^2 for least drag
rho = 1.225;              % Density in kg/m^3
v = 25;                   % Velocity in m/s
drag_forces = 0.5*rho.*v.^2.*area.*cd 

% GRAPH PLOTS
plot(drag_forces,cd);
xlabel('Drag forces');
ylabel('Drag coefficients');
grid on

OUTPUT 2:

GRAPH 2: