Python Report on: - Study Drag Force coming on Cyclist.

Step 1: Studied Drag Force formula.

FD = Drag Force, N

Cd = Co-efficient of drag, no unit

A = Area, m^2

Rho = Density of Fluid, kg/m^3

V = Velocity, m/sec

Step 2: Search values of drag coefficient for various shapes on the internet.

As per the given website http://physicalcycling.com/aerodynamic-coefficients/ I have decided to take co-efficient of drag value mentioned in the table: -

Cyclist Co-efficient of Drag
Male:	Runner	Cyclist (Tops)	Cyclist (Hoods)	Cyclist (Drops)	Cyclist (Aero)
Cd	2.0	1.16	1.00	0.88	0.83
A	0.76	0.63	0.40	0.32	0.31

Step 3: Writing A code for Plot of velocity vs. drag force

Firstly we have written all the given values for the program like frontal area & Density of air. As cyclist is moving forward it is experiencing a drag force and it varies as per the frontal area varies. But in this case, we have to consider a constant for the frontal area and vary the only velocity to observe the changes in drag force as per the velocity varies.

So, after getting the given value we have to put it into the drag force formula. We have to take drag force in a 'for loop' as velocity is varying and to calculate all varying velocities.

"""
Code by Ravi Thakur
Subject: Write a program to plot Velocity vs Drag force

"""

import math
import matplotlib.pyplot as pyplot

# Frontal area of cyclist
A = 0.1

# Density of Air 
rho = 1.2

# Array of Drag Force
Drag_force = []
# Velocity Range
V = [2,4,6,8,10,12,14,16,18,20,22,24,26]

# To plot a graph of drag force vs. Velocity
for Velocity in V:
	c_d = 0.8
	Drag_force.append((0.5*rho*c_d*A*Velocity*Velocity))
	
pyplot.figure(1)
pyplot.plot(Drag_force)
pyplot.plot(Velocity)
pyplot.grid()
pyplot.title('Plotted graph of Velocity vs Drag force')

pyplot.xlabel('Velocity')
pyplot.ylabel('Drag_force')

pyplot.show()
​

Step 4: Results

We have got a graph as a curve because we have taken velocity square in drag force formula.

Step 5: Writing A code for Plot of Coefficient of drag vs. drag force

For this plot, we have to observe the results related to the drag force after varying coefficient of drag. The vales of varying drag coefficient have been mentioned above in the table. Again here we have used 'for loop' to calculate the drag force after varying the drag coefficient.

"""
Code by Ravi Thakur
Subject: Write a program to plot  Coefficient of Drag vs Drag force

"""

import math
import matplotlib.pyplot as pyplot

# Frontal area of cyclist
A = 0.1

# Density of Air 
rho = 1.2

# Array of Drag Force
Drag_force = []
# Coefficent of Drag range
C_d = [0.2,0.4,0.6,0.8,1.0,1.2,1.4,1.6,1.8,2.0]

# plot a graph of drag force vs. Coefficent of drag
for c_drag in C_d:
	Velocity = 10
	Drag_force.append((0.5*rho*c_drag*A*Velocity*Velocity))

pyplot.figure(2)
pyplot.plot(Drag_force)
pyplot.plot(c_drag)
pyplot.grid()
pyplot.title('Plotted graph of drag force vs. Coefficent of drag')

pyplot.xlabel('Coefficent_of_Drag')
pyplot.ylabel('Drag_force')

pyplot.show()

Step 6: Results

We have got a graph as an inclined straight line because we have taken the Drag Coefficient to be directly proportional to drag force.