Hi,

I am sure it's a question with some obvious answer, but...

...why is separation of variables not being used for potential flow problems?? Like they use to do with the heat equation.

Thanks,

Gerrit

Because not all solutions can be obtained by separation of variables (the same is true for the heat equation).

However a large number of solutions to the Laplace equation can be obtained simply by writing the equations in a suitable curvilinear coordinate system and applying separation of variables in the new coordinate system (provided your boundary conditions lie on a coordinate surface). This is the origin of most of the "special functions" that appear in mathematics; e.g. Legendre polynomials etc.

Separation of variable requires a homogeneous direction.Sometimes it is possible to obtain one by change of variables.When it becomes impossible then it cannot be used.

-H

Thanks, it seems that I missed something fundamental.