Calculation of Drag Force using MATLAB

1. AIM: To calculate a drag force of a cyclist using MATLAB
2. EQUATION USED:

`F_d=1/2*rho*v^2*a*c_d`

Where;

`F_d` = Drag force UNIT = ( N ) = ( `(kgm)/s^2` )

ρ = Desity of the fluid which is resisting the object

UNIT = (`(kg)/m^3`)

A= Frontal Area UNIT = ( `m^2` )

v = Velocity of object UNIT = (`m/s` )

C_d = Drag coefficient unitless

3.THEORY: When a body moves forward with a velocity “v”, it will experience a resisting force from the opposite direction of its movement. The force will be called Drag Force. The drag force depend on the density “ρ” of the resisting force. And it will faced by the Frontal Area “A” of the body. The appropriate dimentionless number that represent drag of the body is called Drag coefficient “”.

4.OBJECTIVE

• Plot Drag Force vs Velocity graph
• Plot Drag coefficient vs Drag force graph

5. CODE 1 (program for plotting velocity vs dragforce)

 % A programme to calculate drag force on a bicycle 
 clear all
 close all
 clc
 
 % Inputs
 % Drag coefficient
 c_d = 0.9
 
 % Area m^2
 a = 0.3
 
 % Density kg/m^3
 rho = 1.5
 
 % velocity m/s
 v = [1:30];
 
 drag_force = rho*v.^2*a*c_d*0.5;
 
 plot(v,drag_force,'color','r')
 xlabel('velocity')
 ylabel('DragForce')
 
 grid on

• Output

6. CODE 2

(Program for ploting dragforce vs drag coefficient)

 % A programme to calculate drag force on a bicycle 
 clear all
 close all
 clc
 
 % Inputs
 % Drag coefficient
 c_d = [0.1:0.5:1]
 
 % Area m^2
 a = 0.3
 
 % Density kg/m^3
 rho = 1.5
 
 % velocity m/s
 v = 1
 
 drag_force = rho*v.^2*a*c_d*0.5;
 
 plot(c_d,drag_force,'color','b')
 xlabel('DragCoefiicient')
 ylabel('DragForce')
 
 grid on

• Output

6. CONCLUSION

• Programme for Drag Force for a cyclist has been written in MATLAB
• Velocity vs Drag Force graph has been plotted
• Drag Force vs Drag coefficient has been plotted