Exponential decay of solutions of damped wave equations in one dimensional space in  the $L^p$ framework for various boundary conditions

Abstract

We establish the decay of the solutions of the damped wave equations in one dimensional space for the Dirichlet, Neumann, and dynamic boundary conditions where the damping coefficient is a function of space and time. The analysis is based on the study of the corresponding hyperbolic systems associated with the Riemann invariants. The key ingredient in the study of these systems is the use of the internal dissipation energy  to estimate  the difference of solutions with their mean values in an average sense.