Assessment of the Absorption Performance of Sound Absorbing Materials. Use of the Trefftz's Method and of a New Dual Particle Velocity-Pressure Sensor

摘要

Porous absorbing materials are applied in various fields of sound and noise control. The presented work wants to deliver a numerical simulationtool to predict the acoustical behavior of geometrically complex sound absorbing media under various excitations. To achieve this goal, a deterministic method, which is based on the indirect Trefftz’s method and makes use of solution functions of the governing equations to describe the field variables in the region of interest, is extended to analyze the sound field in and above porous absorbers. The model is experimentally validated and used to analyze the sound field in some real-life configurations. Afterwards, an initial impetus is given towards the further analysis of the absorption performance of various kinds of patchworks under different angles of sound incidence and the study of sound propagation overimpedance jumps, with the aid of a model applicable to unbounded problems. Besides the development of the simulation tool, a new dual particle velocity-pressure measurement technique is presented.