释义 |
Heat Conduction Equation--DiskTo solve the Heat Conduction Equation on a 2-D disk of radius , try to separate the equation using
 | (1) |
Writing the and terms of the Laplacian in Spherical Coordinates gives
 | (2) |
so the Heat Conduction Equation becomes
 | (3) |
Multiplying through by gives
 | (4) |
The term can be separated.
 | (5) |
which has a solution
 | (6) |
The remaining portion becomes
 | (7) |
Dividing by gives
 | (8) |
where a Negative separation constant has been chosen so that the portion remains finite
 | (9) |
The radial portion then becomes
 | (10) |
 | (11) |
which is the Spherical Bessel Differential Equation. If the initial temperature is and the boundarycondition is , the solution is
 | (12) |
where is the th Positive zero of the Bessel Function of the First Kind . |