Flow over Bicycle using MATLAB

AIM : To create a Matlab program to calculate drag force against a cyclist.

Objectives :

• Create a code to calculate drag force against a cyclist.
• Plot the graph for Velocity vs Drag force.
• Plot the graph for Drag Co-efficient vs Drag force.

CODE :

%% Flow over a bicycle for calculating Drag force for plotting Velocity and Drag force

clear all 
close all
clc

% Density (kg/m^3)
rho = 1.2

% Frontal Area (m^2)
A = 0.1

% Velocity (m/s)
v = [1:25]

% Drag Coefficient (Unit less)
C_d = 0.8

% Drag Force
Drag_force = 0.5*rho*A*v.^2*C_d

plot(v , Drag_force , 'g') 
xlabel('Velocity')
ylabel('Drag force')
grid on



%% Flow over a bicycle for calculating Drag force and plotting Drag cofficient vs Drag force

clear all 
close all
clc

% Density (kg/m^3)
rho = 1.2

% Frontal Area (m^2)
A = 0.1

% Velocity (m/s)
v = 15

% Drag Coefficient (Unit less) for different shapes
streamlined_body = 0.04;
cone = 0.50;
short_cylinder = 1.15;
half_sphere = 0.42;
sphere = 0.47;
C_d = [streamlined_body half_sphere sphere cone short_cylinder]

% Drag Force
Drag_force = 0.5*rho*A*v^2*C_d

plot(C_d, Drag_force , 'r') 
xlabel('Drag coefficient of various shapes')
ylabel('Drag force')
grid on

STEPWISE EXPLANATION OF THE CODE :

1. Start with the general commands clear all, close all and clc which will clear the window and close all the recents plots if any exists.
2. Assign the input values for Velocity,Drag coefficient,Frontal Area,Density of air.
3. Use the plot command to plot velocity on x axis & drag force on y axis and label it.
4. Now, for calculation of drag force and results give the values of drag coefficient for different shapes and calculate drag force by using formula.
5. Plot the graph for drag coefficient against the drag force using plot command and label for X & Y axis respectively.

RESULTS :

• Here, the plot shows the curve for velocity vs Drag force when the velocity increases so does the drag force also increases with it for the same Frontal area.

• Here, is the plot for 2nd program. The output tells us that for different drag coefficients for various shapes the drag force changes with respect to it. As, the Drag coefficient(C_d) increases for different shapes so thus, the Drag force also increases with it linearly.

1st program Output for Velocity vs Drag force

• Here, the velocity increases from 1 m/s to 25 m/s so thus, the Drag force inreases with it from 0.0480 to 30 N respectively.

2nd program Output for Drag Coefficient vs Drag force

• Here, the drag coefficient increases for different shapes from 0.04 to 1.1500, correspondingly the drag force also increases with it from value 0.5400 to 15.5250 respectively.

Conclusion -

Hence, we had sucessfully created a code and calculated the drag force over the cyclist and obtained its output plots respectively.