Flow over Bicycle
# Attempt 1
You scored 50/50 in this challenge. Please see the below table for details
| Requirement | Explanation | Maximum Marks | Marks Obtained |
|---|---|---|---|
| Code | Code should be attached with comments | 20 | 20 |
| Outputs | Output plots/videos must be attached | 10 | 10 |
| Explanation | Code and outputs must be explained | 20 | 20 |
Grading Comments:
Remarks
good!
Your Question
Write a Matlab program to calculate drag force against a cyclist.
The factors involved are Velocity,Drag coefficient,Frontal Area,Density of air.
- Write a program to plot Velocity vs Drag force.
- Write a program to plot Drag Co-efficient vs Drag force.
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Hint: For the same frontal area, the coefficient of drag varies for different shapes. Look for values of drag coefficient for various shapes in the internet.
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Your Answers
Aim :- To write a program in matlab to calculate drag force against a cyclist.
Objective :- The main objective is to
- Write a program to plot Velocity vs Drag force. &
- Write a program to plot Drag Co-efficient vs Drag force
Formula /Governing Equation:- formula to find the drag force is given as :-
`F_d = 1/ 2 × ρ × A × v^2 × C_d`
Where , Fd = Drag force (N)
`rho`= Density (Kg/`m^3`)
A = Frontal area (`m^2`)
v = velocity (m/s)
Cd = Drag coefficient (unitless)
Theory :- Drag force is the resistance forced applied on a body moving in a forward motion , it is just like an opposite force action on the body which is travelling in a particular direction
- Let’s take an example of a cyclist riding a bicycle at an uniform velocity say (v) in a particular direction , let (A) be the frontal area of the cyclist ,the force acting on the frontal area and causing air resistance action is called as drag force.
Body of the content :-
- Programing language used Matlab Online.
- Starting the program by using comments.
- providing the values for Velocity , Drag coefficient ,Frontal Area ,Density of air.
- Using the formula to calculate dragforce , formula:- drag force = rho*A*v.^2*Cd*0.5;
- Using plot commant to plot a graph by providing x&y label .
- To plot a graph of velovity vs dragforce the velocity values are placed in an array upto a specific limit, ie say velocity [1 to 100] to obtain a smooth curve
- Similarly to plot a graph for Drag Co-efficient vs Drag force the C_d values are taken in an array
Matlab Program :-
1 . program to plot a graph for Velocity vs Drag force.
% program to calculate drag for on a bicycle
close all
clear all
clc
% inputs used in program
% Drag coefficient
c_d = 0.8
% Frontal Area in (m^2)
A = 0.2
% Density in (kg/m^3)
rho = 1.2
% velocity
v = [1:65];
% Formula for Drag-force
drag_force = rho*A*v.^2*c_d*0.5;
plot(v , drag_force)
grid on
xlabel ('velocity')
ylabel ('drag force')Command window exicution:-
2 . program to plot a graph for Drag Co-efficient vs Drag force.
% program to calculate drag for on a bicycle
close all
clear all
clc
% inputs used in program
% Drag coefficient
c_d = [ 1:50 ];
% Frontal Area in (m^2)
A = 0.2
% Density in (kg/m^3)
rho = 1.2
% velocity
v = 0.25
% Formula for Drag-force
drag_force = rho*A*v.^2*c_d*0.5;
plot(c_d , drag_force , 'color', 'r')
grid on
xlabel ('Drag coefficient')
ylabel ('Drag force')Command window exicution:-
Result :- Thus we can create plot/graph by the above program for Velocity vs Drag force & Drag Co-efficient vs Drag force .
-below is the graph plotted for the Velocity vs Drag force & Drag Co-efficient vs Drag force
1. graph for Velocity vs Drag force.
x-axis is velocity & y-axis is for drag force , more the values for velocity results in smoother curve line is obtained . likewise when velocity values increases dragforce values also increases .
2. graph for Drag Co-efficient vs Drag force.
x-axis is drag-coefficient & y-axis is for drag force . it is seen that when C_d values increases dragforce values also increases .