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Subject: Re: Convective diffusion equation in 2D
Date: Mon, 17 Dec 2007 23:50:40 +0000 (UTC)
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 dantimatter <dantimatter@gmail.com> wrote in message
<1186153073.038814.223160@d30g2000prg.googlegroups.com>...
> 
> Hello all,
> 
> I'm trying to find a nice and neat way to numerically
solve the
> convective diffusion equation
> 
> da/dt = D (d^2/dx^2 + d^2/dy^2) a - v da/dx
> 
> where a is the concentration of my solute, D is the diffusion
> constant, and v is the surrounding fluid velocity in the x
direction.
> I thought that there was a small chance that maybe someone
else here
> has attempted something similar.
> Is it even possible to solve this equation? As always, any
suggestions
> would be much appreciated.
> 
> Cheers,
> Dan
> 


My friend, you have just opened the third biggest can of
worms in classical physics (IMHO!).

Check the following link out. It's not matlab per-se, but
there are matlab import-export routines for the files. If
you know C++ (or are relatively fearless / have a bit of
time on your hands), it's a very efficient solver for pretty
much any PD Equation... I think one of the examples might
include a convection-diffusion setup. To give you an idea, I
didn't know C++, and it took me about a week to get up to
speed with this solver, using a C++ textbook as a guide.

Please note that it's a pretty specialised solver (spectral
domain, for efficiency) and there are a lot of similar
things out there on the web. Many of them will be simpler to
implement, although beware there is a minefield of badly
written code, too!

http://wissrech.ins.uni-bonn.de/research/projects/AWFD/

If you need some help setting it up, I may be able to offer
advice (or at least some really heavily commented code that
I've developed). Fire off an email to the address shown
(removing spam labels, of course)

Good luck!

Tom Clark