2D Conduction Problem

[yeu_shiuan]

Everyone

I have stuck in the problem of 2D conduction problem by using matlab, here is the following question:

Consider a long bar of square cross section (1.0 m to the side) and of thermal conductivity 2 W/m.K. Three of these sides are maintained at a uniform temperature of 300°C. The fourth side is exposed to a fluid at 100°C for which the convection heat transfer coefficient is 10 W/m2.K.

a)Using an appropriate numerical technique with a grid spacing of 0.2m, determine the midpoint temperature and heat transfer rate between the bar and the fluid per unit length of the bar.
b)Reducing the grid spacing by a factor of 2, determine the midpoint temperature and heat transfer rate. Plot the corresponding temperature distribution across the surface exposed to the fluid. Also, plot the 200 and 250°C isotherms.

Hopefully that anyone can give me some tips to do it. Thanks.

[VBAhack]

Since nobody replied, you might try here:

http://www.physicsforums.com/

[new fish]

what you need is finite differences.

i'm not that familiar with matlab but

what you need to do is take a slice of the bar (the square csa)
and divide it into a grid so that you'll have 25 smaller squares
the corner of each little square will be a node, and you have to generate an equation for each node.

for the 3 sides kept at 300 degrees, each node is obviously = 300

for the internal nodes you must write a "computational molecule" which is based on the 4 adjoining nodes (up down left and right) and the material properties (thermal conductivity)

for the top nodes (convective cooling) agian will depend on the four surronding nodes, left right and down are going to be conduction, you must also inculde an "imaginary" node above the bar which is held at 100 degress and will be convective. [newtons law of cooling]

you'll need to have a timestep and initial tempratures.
i think you could use crank nicholson

although::: if you're given this question i presume you know the steps to take to solve it, maybe you asking for specific help wrt matlab??