particles-demo

Demonstration of Maxwell-Boltzmann speed distribution for particles in a box

Table of Contents

• Usage
• Options
• Note
• Issues with Chrome

Usage

1. Open index.html with a modern web browser.

   • WARNING: Internet Explorer is not supported, and using it may lead to unexpected behaviors.
   • Note: Chrome cannot run this program properly when the program is executed as a local file. More information can be found on Issues with Chrome section of this file.

2. Open debug console. Typically it is bound to F12 on keyboard.

3. Execute

   simulate()

   or

   simulate({
     tMax: 10000,
     dt: 50,
     n: 100,
     ...
   })

   More options can be found on Options section of this file.

4. The simulator terminates after tMax (default: 10,000) milliseconds. If you want to stop the simulation earlier, you can use the return value of simulate() function, like the code below.

   let instance
   instance = simulate()
   
   // Stopping the simulation
   instance.terminate()

Options

Name	Default	Description
width	320	Box width (px)
height	240	Box height (px)
r	2	Particle radius (px)
tMax	10000	Max simulation time (ms)
dt	50	Time interval between screen refreshes (ms)
timestamp	10	Number of screen refreshes between timestamps
n	100	Number of particles
vMean	0.08	Target mean speed of particles (px/ms) *
dist	'uniform'	Speed distribution of particles (uniform / delta)
bins	Math.ceil(Math.log2(n)) + 1	Number of screen refreshes between timestamps
xMax	3 * vMean	Max value of x in histogram plot
yMax	1.5 * pdf(vMean) **	Max value of y in histogram plot

* vMean may not be equal to actual mean speed of the particles.
** pdf() is the Maxwell-Boltzmann distribution function.

Note

simulate() function returns the web worker object responsible for calculating positions and velocities of the particles.

Issues with Chrome

• Note: If you are running the code in a web server, this section does not apply to you. The program will work as expected without any modifications.

Chrome does not allow web worker script from local files to be executed. A workaround is present, and implemented in files in the chrome branch.

How to Download Files in chrome Branch:

1. Visit the git repository.
2. Above the list of files, find the button named "Branch: master"
3. Among the dropdown list of branches, find "chrome".
4. On the right side of the button showing branches, click "Clone or download".
5. Click "Download ZIP".