#### Spectral Analysis – a Fourier transform tutorial – part #3

30/03/2011

While the previous sections of the tutorial handled the basic formulas behind building a Fourier model and creating a set of input functions, this section deals with formula implementation on the spreadsheet, the brief VBA code and the charting of the Fourier transform components.

#### Spectral Analysis – a Fourier transform tutorial – part #2

29/03/2011

In this tutorial the Excel implementation of a Fourier transform is discussed. Seven input signals are created among which sinusoidal, rectangular and combinations of them. A Dirac impulse, an amplitude modulated (AM) signal and a frequency modulated (FM) signal are also added among the input signal options.

#### Spectral Analysis – a Fourier transform tutorial – part #1

28/03/2011

This is a basic tutorial about implementation of a standard Fourier transform model in Excel. It is not an introduction to Fourier analyis. You could choose to familiarize yourself with the subject before proceeding with this tutorial. Solving a few Fourier transform excersises would be of help too. Essentially, this part shows you how to adapt the general Fourier formula for a continuous real signal to a sampled signal having a limited number of samples.

#### Brownian Motion Animation – a 2D random walk diffusion tutorial

27/03/2011

This is a tutorial about the creation of an animated diffusion model based on the random walk principle. There are two different models, one based on a lattice style diffusion (the particles can move in a series of steps of a fixed distance, but only in multiples of a 90 degree angles: 0, 90, 180, 270) and one based on a fluid style diffusion in which the particles can move…

#### A 2D Random Walk Animation Tutorial

26/03/2011

This tutorial explains how to build two animated random walk models, one where the particle is confined to square grid and one where the particle is free to step in any direction. The first model is adequate for modeling particle movement in solids while the second is more fit for modeling particle diffusion motion in fluids.

#### A 2D Random Walk Model – the “drunk man” animation

25/03/2011

This is a model simulating a two-dimensional random walk in two variants, one by using a digital angle (in 90 degrees increments) and one using an analog angle between zero and 2*pi.  This type of model (similar to the walk of a very drunk man) pertains very well to numerically solving Monte Carlo diffusion type problems.  It is a brute force model using a lot of computer time and resources typically employed when the…

#### The Melting Snow Castle – a diffusion model application

24/03/2011

This is an application to the previously derived 2D diffusion (heat transfer) model. The snow melting process is very similar to diffusion or heat transfer. Just open the model and hit “Start-Pause” to see for yourself. It is a 2003 model or earlier. I wasn’t able to run it in 2007 with animation but I’ve got some friends who managed to run it with no problem (except speed). The graphics is very…

#### Building a Dynamic Two Dimensional Heat Transfer Model – part #2

23/03/2011

This is the second half of the tutorial which shows how to build a basic animated 2D heat transfer model in Excel.

#### Building a Dynamic Two Dimensional Heat Transfer Model – part #1

22/03/2011

Here is the first part of a tutorial which shows how to build a two dimensional heat transfer model in Excel. The presentation shows how to partition a square plate in elementary elements on which the simplest form of the heat storage and heat transfer equations can be applied. The numerical form of the final temperature formula is derived .

#### A Basic 2D Animated Heat Transfer Model (a diffusion model too)

21/03/2011

Here is a basic 2D heat transfer model. The first  five worksheets model square plates of 30 x 30 elements. The last worksheet is the model of a 50 x 50 plate. You can modify the initial temperature by hand within the range C21:AF240. It is also a diffusion model. It uses the storage and transport equations derived in the previous tutorials. The temperature calculations are done all  with a single repetitive…