释义 |
Helmholtz Differential Equation Polar CoordinatesIn 2-D Polar Coordinates, attempt Separation of Variables by writing
| (1) |
then the Helmholtz Differential Equation becomes
| (2) |
Divide both sides by
| (3) |
The solution to the second part of (3) must be periodic, so the differential equation is
| (4) |
which has solutions
Plug (4) back into (3)
| (6) |
This is an Euler Differential Equation with and . The roots are .So for , and the solution is
| (7) |
But since blows up at , the only possible physical solution is . When , , so
| (8) |
But since blows up at , the only possible physical solution is . The solution for isthen
| (9) |
for , 1, ...and the general solution is
| (10) |
References
Morse, P. M. and Feshbach, H. Methods of Theoretical Physics, Part I. New York: McGraw-Hill, pp. 502-504, 1953. |