Modeling-Diffusion-Limited-Aggregation

Authors: Vinay Rajur

Last Updated: 6/3/2015

Summary:

A project to simulate the physical mechanism underlying some types of crystal formation processes. The goal of this project is to study the effectiveness and limitations of the numerical model in simulating the process of Diffusion Limited Aggregation.

(See full project report in pdf file: Modeling Diffusion Limited Aggregation)

Operation Instructions:

To run the simulation clone the Source_Code directory and the file Final.cpp which will output the simulation results to the file "pos.dat". Move this file into the same directory as plott2.m and running that script will plot the particle distribution generated from the simulation and will also output the results of various analyses on the data.

Implementation Overview:

The simulation is written in C++ and uses Monte-Carlo methods to implement a series of random walks on a set number of particles. The simulation is initialized with a seed particle and one random walker particle. At each step in the random walk, various conditions are checked to see if the random walker will bind to the aggregate structure in its current position. Once the particle is bound a new random walker is randomly initialized. The simulation runs until a set number of particles are bound.

Repository Overview:

Project Report: Modeling Diffusion Limited Aggregation.pdf

Source Code: Contains C++ files which are the numerical model implementation as well as MATLAB files for plotting and data analysis

LaTeX Source: Contains LaTeX source files used for creating the project report

Directory of Key Files:

Source Code/Final.cpp

Script to initialize parameters, run DLA simulation, and output particle locations to text file

Source Code/r_walk.h

Function to test properties of the random walk model used in final.cpp

Source Code/p_neighbors.h

Function to calculate and return the probability (as a function of neighboring particles)of a particle sticking to the aggregate

Source Code/p_curvature.h

Function to calculate and return the probability (as a function of local curvature of the aggregrate) of a particle sticking to the aggregate

Source Code/p_coeff.h

Function to calculate and return the probability (as a constant-valued function) of a particle sticking to the aggregate

Source Code/arrayt.hpp

C++ array implementation supplied by professor (not authored by me)

Source Code/MATLAB (plotting)/circularity.m

Script to calculate circularity of aggregate structure

Source Code/MATLAB (plotting)/plott2.m

Script to read output data file containing particle locations and produce plot of aggregrate and calculate property values of the simulation

Source Code/MATLAB (plotting)/rwalkstest.m

Script to analyze output data from r_walk.h

LaTex Write Up/Final Project.tex

LaTeX file for project report

LaTex Write Up/Final Project.bbl