Matlab program for Drag Force calculations of flow over bicycle

%% Program to calculate drag force over bicycle
clc
clear all 
close all


%% PART 1 :- Calculating drag force and plotting using a user defined function

% 1.) If using Matlab 2017 and ahead, the file can be runned directly.
% 2.) If using Matlab 2016 or before, please cut and copy the function at the end of program in
%     another file and save it with name Drag_force1.m

% Inputs

c_d = 0.8;      % Drag coeffiecient
A = 0.1;        % Frontal area (m^2)
rho = 1.2;      % Density of air (kg/m^3)

v =[1:50];      % Velocity of bicycle (m/s)

DF1 = Drag_force1(c_d,rho,A,v);       % A function named Drag_force1 calculating and plotting the drag force vs velocity 



%% PART 2 :- Document the drag coefficient for various shapes and try to plot drag force as a function of drag coeffiecient

%{
Drag coefficients for various shapers

1. Sphere = 0.47
2. Half-sphere = 0.42
3. Cone = 0.50
4. Cube = 1.05
5. Angled cube = 0.80
6. Long Cylinder = 0.82
7. Short Cylinder = 1.15
8. Streamlined body = 0.04
9. Streamlined half body = 0.09

Source :- Wikipedia/Drag_coefficient

%}

cd1 = [.47 .42 .50 1.05 .80 .82 1.15 .04 .09];  % Cd for various shapes

figure(2)
v1 = 10;             % velocity assumed for comparision (m/s)

DragForce = 0.5*cd1*rho*A*v1.^2;

scatter(cd1,DragForce)
title('Plotting Drag Force vs Drag coefficient')
xlabel('Cd');
ylabel('Drag Force (N)');
grid on;
grid minor;


%% Function for PART 1 
Cut and copy this part in new file if using Matlab 2016 or before and save as
Drag_force1.m

function [DragForce] = Drag_force1(cd,rho,A,v)
%DRAG FORCE 
%cd - drag coefficient; 
%rho - density; 
%A - frontal area; 
%v - velocity

DragForce = 0.5*cd*rho*A*v.^2;

plot(v,DragForce)
title('Plotting Drag Force vs Velocity using function')
xlabel('Velocity (m/s)');
ylabel('Drag Force (N)');
grid minor;
end

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Conclusion :

1) On increasing the velocity, the drag force is increased in quadratic sense.

2) Increasing coefficient of drag results in drag force is increased linearly.