FLOW OVER BICYCLE

AIM: To calculate drag force against a cyclist using MATLAB.


GOVERNING EQUATION: FDRAG FORCE=1/2.rho.a.v^2.c_d

UNITS:
DRAG FORCE- (N)
DENSITY-(Kg/m^3)
A FRONTOL AREA- (m^2)
V VELOCITY- (m/s)
c_d COEFFICIENT OF DRAG-(unitless)

THEORY:

Drag force- A drag force is the resistance force caused by the motion of the body through a fluid ,such as water or air.It is a type of frictional force. It acts                   opposite to the  direction of the oncoming flow velocity.In this case cyclist is experiencing a drag force as he is against the wind.
            Drag force depends on the following factors-
            (.)Shape of the body(.)Type of surrounding fluid(.)The velocity of the body


OBJECTIVE: 1)To plot a graph between velocity vs Drag force.
           2)To plot a graph between Drag coefficient vs Drag force.


CODE:  MATLAB CODE 1(VELOCITY VS DRAG FORCE)

clear all
close all
clc

%A = FRONTOL AREA

%INPUTS 

%DRAG coefficient
c_d = 0.2

%velocity
v = [2 3 4 5 6]

%DENISTY Kg/m^3
rho = 1.2 

%AREA m^2
a = 0.6


drag_force = 0.5*c_d*v.^2*a*rho
plot(drag_force,v ,'linewidth',3'color','b')
xlabel('drag coeffient')
ylabel('velocity')
grid on

RESULT: Drag force increases exponentially on increasing the velocity of the cyclist.
 
MATLAB CODE2(DRAG COEFFICIENT VS DRAG FORCE)

clear all
close all
clc

%INPUTS 
%DRAG COEFFICIENT (UNITLESS)
c_d = [0.1 0.2 0.3 0.4 0.5]

%DENSITY (Kg/m^3)
rho= 1.4

%FRONTOL AREA (m^2)
a = 1.2

%VELOCITY (m/s)
v = 2

%outputs 
%formula to calculate drag force 

drag_force =rho*a*c_d.*v^2*0.5

%graph of drag coefficient vs drag force 
plot(c_d,drag_force,'linewidth',3,'color','b')
xlabel('drag coefficient')
ylabel('drag force')
grid on

RESULT:Drag force increases linearly with the drag coeffiecient.

CONCLUSION:
1)From velocity vs drag force graph we can conclude that as the speed of the cyclist increases,
the drag force increases in an exponential manner and varies with v^2.
2)From drag force vs drag coefficient, we conclude that larger the frontol area , more the drag coefficient which in turn increases the drag force.Hence in order to reduce the drag force , the frontol area must be as low as possible.