Calculation of drag on cyclist using MATLAB

AIM:

To calculate drag force experienced by cyclist using matlab.

GOVERNING EQUATION :

`F_(d=frac{1}{2}rhoAV^2C_(d`

Where

• `F_(d`(N) = Drag force
• `rho`(Kg/`m^3`) = Mass density
• A(`m^2`) = Frontal Area
• V(m/s) = Velocity
• `C_(d`= Drag coeficiient

Drag force: Drag is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid.This can exist between two fluid layers (or surfaces) or a fluid and a solid surface.

Frontal area: Frontal area is projected area of moving body normal to it on screen.

Drag coefficient: Drag coefficient is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment The drag coefficient is always associated with a particular surface area.

shape Drag coeficient

Streamlined body 0.04

Streamlined halfbody 0.09

Halfsphere 0.42

Cone 0.50

Long cylinder 0.82

Cube 1.05

OBJECTIVES OF THE PROJECT:

1.To calculate Drag force for different velocities

2.To calculate Drag force for different shapes of different Drag Coefficient

PROGRAM 1:

Programming language: MATLAB

% A program to calculate the drag force on a bicycle w.r.t velocities of  bicycle

clear all
close all
clc

% Inputs

% Drag coeficient
c_d = 0.8;

%Area m^2
A = 0.1;

%Density kg/m^3
rho = 1.2;

% Velocity range
v = [1 :50];

drag_force = rho*A*v.^2*c_d*0.5;


plot(v, drag_force);
title('Drag force vs Velocity');
xlabel('Velocity');
ylabel('Drag force');
grid on;

Graph 1

PROGRAM 2:

Programming language: MATLAB

% A program to calculate the drag force on a bicycle w.r.t drag coefficients

clear all
close all
clc

% Inputs

% Drag coefficient for different shapes
c_d = [0.04, 0.09, 0.42, 0.50,  0.82, 1.05];
names = {'Steamlined body', 'Streamlined halfbody', 'Halfsphere', 'Cone', 'Long cylinder', 'Cube'};

%Area m^2
A = 0.1;

%Density kg/m^3
rho = 1.2;

% Velocity
v = 100;

drag_force = rho*A*v.^2*c_d.*0.5;


plot(c_d, drag_force,"b-*","linewidth",1);
title('Drag force vs Drag coefficients');
text(c_d, drag_force, names);
xlabel('Drag Co-efficient');
ylabel('Drag force');
grid on;

Graph 2

CONCLUSION:

1.From graph 1, we can see drag varies parabollically with respect to velocity,it means drag force is directly proportional to square of velocity if frontal area, mass density and Drag coefficient are constant

2.From graph 2, we can see drag varies linearly with respect to Drag coefficient of different shapes, it means drag force is directly proportional to Drag coefficient if frontal area, mass density and Velocity are constant.