boundary integral constraint
 

Hello

I have nonlinear PDE(1D) with boundary integral constraint:

1)dc/dt = f(c, d/dx(dc/dx), ...)

2)boundary integral constraint : Integral(dc/dt, x) = constant (constant - user defined value, x - integration variable)

3)also Initial Condition and Neumann boundary presents.

I'm novice in this direction, and I have access to Comsol.

I dont know how I can apply this integral constraint?

If you know how to make this in Comsol or another software please tell me concrete,(if you can - it's desirable with links on examples or books or tell more concrete)

Sincerely yours, dotfix