Assuming your problem is well posed, the physics is reasonable and your code is correct, then welcome to the joys of nonlinear problems. Even if the theory is trivial, getting it to work can be a nightmare. Here are some tips.
Assuming your problem is well posed, the physics is reasonable and your code is correct, then welcome to the joys of nonlinear problems. Even if the theory is trivial, getting it to work can be a nightmare. Here are some tips.