Vibrating membrane
= Vibrating membrane
A physical sheet under uniform isotropic tension per unit length T and with <mass> per unit area $\rho$ has small transverse displacement satisfying $\partial_t^2\psi=c^2\nabla^2\psi$, where $c^2=T/\rho$. Fixed edges impose zero displacement. This mechanical membrane model neglects bending stiffness, large slopes and <dissipation>.