solving the equation of propagation using simulink too see the dispersion effect

l'equation de propagation de l'enveloppe de l'impulsion sans effet non lineaire

[John D'Errico]

Is S the same thing as s? If not, then you have a problem.

I don't think Simulink can solve a PDE. You probably need to use a tool like pdepe instead. The second order time derivative can be dealt with by creating a system of two PDEs, each first order in the time derivative.