dirtybomb
Version:
A dirty bomb model
78 lines (69 loc) • 2.41 kB
JavaScript
/**
* Created by austin on 6/16/16.
* @file DynamicGaussianDecayPuff.js
*
*/
import DynamicGaussianPuff from './DynamicGaussianPuff';
/**
* Adds half life decay to the Dynamic Puff
*/
class DynamicGaussianDecayPuff extends DynamicGaussianPuff {
/**
*
* @param {Atmosphere} atmosphere
* @param {Source} source
* @param {number} massReleased
* @param {number} halfLife - seconds
* @param {array} [center] - Manually set the center, defaults to (0,0,0)
*/
constructor(atmosphere, source, massReleased, halfLife, center) {
super(atmosphere, source, massReleased, center);
/**
*
* @type {number}
* @private
*/
this._halfLife = halfLife; // Usually the half-life of the pollutant
/**
*
* @type {number}
* @private
*/
this._decayCoeff = 0.693 / halfLife;
}
/**
*
* @returns {number}
*/
get halfLife() {
return this._halfLife;
}
/**
* Read URAaTM pg 281 - 285
* @see https://books.google.com/books?id=bCjRtBX0MYkC&pg=PA280&lpg=PA280&dq=gaussian+decay+plume&source=bl&ots=oJbqk8OmIe&sig=GqzwcwVfbk_XUR6RztjSeVI0J20&hl=en&sa=X&ved=0ahUKEwih4OS7zpTNAhWq5oMKHeM_DyIQ6AEINjAF#v=onepage&q=gaussian%20decay%20plume&f=false
* @param {number} x - downwind distance (m)
* @param {number} windSpeed - at source _height (m/s)
* @returns {number} Decay term
*/
getDecayTerm(x, windSpeed) {
if (this._decayCoeff == 0) {
return 1;
} else {
return Math.exp(- this._decayCoeff * (x / windSpeed));
}
}
/**
* Takes into account the decay term, as seen in URAaTM pg 281
* @see https://books.google.com/books?id=bCjRtBX0MYkC&pg=PA280&lpg=PA280&dq=gaussian+decay+plume&source=bl&ots=oJbqk8OmIe&sig=GqzwcwVfbk_XUR6RztjSeVI0J20&hl=en&sa=X&ved=0ahUKEwih4OS7zpTNAhWq5oMKHeM_DyIQ6AEINjAF#v=onepage&q=gaussian%20decay%20plume&f=false
* @override
* @param {number} x - downwind (m)
* @param {number} y - crosswind (m)
* @param {number} z - _height (m)
*/
getConcentration(x, y, z) {
let unDecayed = super.getConcentration(x, y, z);
let decayTerm = this.getDecayTerm(x, this.atmosphere.windSpeed);
return unDecayed * decayTerm;
}
}
export default DynamicGaussianDecayPuff;