Generation and suppression of flutter echoes in spherical domes

Abstract

Flutter echoes in enclosures with spherical domes are analysed by means of a ray model. After the conditions for the settlement of flutter are established, a ray model is developed to inquire about the achievement of these conditions in enclosures. The model is applied to explain the flutter echo formation in enclosures including a flat floor and a spherical dome, for R/H ranged up to 4 that include most common situations (R is the dome radius and H the dome height from the floor). The characteristics of the flutter echoes suggest the adequacy of using reflectors for destroying that acoustical phenomenon. Information about size and position of reflectors is also obtained from the ray model. Some experiments on a full size enclosure and on a 1: 20 acoustic scale model are also reported.