Week 1 - Flow over Bicycle

Definition of Drag force:- According to Merriam-Webster drag force is a "retarding force acting on a body moving through a fluid (such as air) in parallel and opposite direction to the direction of motion. It is retardation due to friction."

Formula Used :-

`D = frac{1}{2} rho upsilon^2 C_{D} ​ A`

where DD = Drag Force (Newton)

`rho = Density of Air frac{kg}{m^2}`

`upsilon = Velocity (frac{m}{s})`

`C_{D}`= Drag Coefficient (Dimensionless)

`A = F r o n t a l A r e a (m^2)`

Procedure to calculate Drag Force in MATLAB :-

% Project Title:- Flow over bicycle

clear all
close all
clc

% Input Data
% Density of Air (rho) in kg/m^3
rho = 1.225;

% Frontal Area(A) in m^2
A= 0.1;


% For plot between velocity and Drag force(Drag coefficient constant and
% velocity is varying.)

% Drag coefficient(c_d contain drag coefficient 0.8 for bicycle)
c_d = 0.8;

%Velocity range (velocity taken from 1 to 50 m/s) 
v_range = 1:50;

% Calculation of Drag force of varying velocity
% Using formula of Drag force 

drag_force_velocityrange = 0.5*rho*A*v_range.*v_range*c_d;

% Solution plot of velocity vs drag force
subplot(1, 2, 1);  % subplot is use to plot both figure in single window.

plot(v_range,drag_force_velocityrange,'b');
xlabel('Velocity in m/s');
ylabel('Drag force in Newton');
title('Velocity v/s Drag force');
grid on;

% Input for plot Dag coefficient v/s drag force where velocity is constant
% and drag coefficient has multiple values
% Drag coefficient range
c_d_range = 0.5:0.1:2.0;

% Velocity in m/s
v = 25;

% Drag force for varying drag coefficient
drag_force_coefficientrange = 0.5*rho*A*v*v*c_d_range;

% Solution plot of Drag coefficient vs drag force.
subplot(1, 2, 2);
plot(c_d_range,drag_force_coefficientrange,'r');
xlabel('Drag coefficient');
ylabel('Drag force in Newton');
title('Drag coefficient v/s Drag force');
grid on;
%end of the program

Result and Conclusion :- After the execution of the program following figure window is display.