Calculation of Drag force due to the flow over bicycle using and comparing with varying Drag coefficient and Bicycle Velocity

% Drag force with varying bicycle velocity

clear all
close all
clc

% Density of air
DA=1.225;

% Drag Coefficient (~0.6 is considered to be a rough estimate)
C_d=0.6;

% Frontal Area
F_A=0.370;

% Velocity of the Vehicle
V=linspace(10,30,15)

% Drag Force Calculations
D_f=(1/2)*DA*C_d*F_A.*V.^2

% Drag force vs Velocity graph
plot(V,D_f)
xlabel('Velocity')
ylabel('Drag Force')
grid on

From the figures below, the following two conclusions were made:

• In the figure with varying drag coefficient, we can conclude that there the drag force is linearly proportional to the corresponding drag coefficient value.

• For every increase/increment in the drag coefficient, we see a linear increase in the drag force.

Now from the figure with varying bicycle velocity:

• There is an exponential rise in the drag force for every increase in velocity, and as the drag force increases with the factor of multiplication of the corresponding velocity, we see a significant rise in drag force.

Now from the two figures we can incur that, with changing drag coefficient for constant velocity, the drag force only increases within a specified min and max range (0.1 - 0.9), but for the velocity, the drag force multiplies itself with the factor of the value of velocity hence making it very significant.

% Drag force with varying drag coefficient

clear all
close all
clc

% Density of air
DA=1.225;

% Drag Coefficient
C_d=0.1 + (0.9-0.1)*rand(1,5)

% Frontal Area
F_A=0.370;

% Velocity of the Vehicle
V=15;

% Drag Force Calculations
D_f=(1/2)*DA.*C_d*F_A.*V^2

% Drag force vs Drag Coefficient
plot(C_d,D_f)
axis([0.1 1.0 5 47])
xlabel('Coefficient of Drag')
ylabel('Drag Force')
grid on