2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/86607In this brief report, the group velocity of the eigen-modes in sonic crystals is derived, and shown to equal the averaged energy velocity of the eigen-modes. How the group velocity can be used to describe acoustic energy flows in sonic crystals is discussed.4 pagesClassical PhysicsGeneral Physicstext