Decay estimates of solutions for the wave equations with strong damping terms in unbounded domains

This paper is concerned with some uniform energy decay estimates of solutions to the linear wave equations with strong dissipation in the exterior domain case. We shall derive the decay rate such as (1 + t)E(t)less than or equal toC for some kinds of weighted initial data, where E(t) represents the total energy. Our method is based on the combination of the argument due to Ikehata-Matsuyama with the Hardy inequality, which is an improvement of Morawetz method. Copyright (C) 2001 John Wiley & Sons, Ltd.