NONLINEAR EFFECTS IN FINITE-AMPLITUDE WAVE-PROPAGATION THROUGH ORIFICE PLATE AND PERFORATED PLATE TERMINATIONS

In reference [1], it has been shown that low-frequency acoustic power is absorbed at orifice plate and perforated plate terminations. Since relatively high-intensity pulses were used in the study reported in reference [1], the indications were that non-linear propagation effects might be the cause of such an energy absorption. In this paper, an extensive study of non-linear effects in finite amplitude wave propagation through orifice and perforated plate terminations is summarized. Experimental investigations were carried out to determine the magnitude of the effects of high-intensity pulse propagation. Experimental results were compared with analytical results derived by using the theory of Cummings and Eversman [2,3]. The acoustic energy absorption mechanism was also studied by means of flow visualization. It has been concluded that the absorption of low-frequency acoustic power is due to non-linear propagation effects, and that its magnitude depends on the porosity of the termination and the intensity of the propagating sound wave. © 1990.