Acoustic attenuation performance of circular expansion chambers with single-inlet and double-outlet

Expansion chambers with single-inlet and double-outlet provide desirable br oadband acoustic attenuation similar to simple (single inlet/outlet) chambe rs and reduce the flow noise and back pressure in exhaust systems. The pres ent study develops a three-dimensional analytical approach to determine the transmission loss of circular expansion chambers with single-inlet and dou ble-outlet, which couples the continuity conditions of the acoustic pressur e and particle velocity at the inlet and outlets with the orthogonality rel ations of Fourier-Bessel functions. The analytical results are compared wit h the boundary element predictions. The acoustic attenuation of the expansi on chambers with single-inlet and double-outlet is then investigated in det ail as a function of the chamber length and the locations of inlet and outl ets. (C) 2000 Academic Press.