ACOUSTIC ATTENUATION PERFORMANCE OF CIRCULAR EXPANSION CHAMBERS WITH OFFSET INLET OUTLET - I - ANALYTICAL APPROACH/

The inlet and outlet locations of expansion chambers can significantly affect the acoustic attenuation performance of the silencer, due to t heir control over the excitation and suppression of higher order modes . By combining the continuity conditions of the acoustic pressure and particle velocity with the orthogonality relations of Fourier-Bessel f unctions at the inlet and outlet discontinuities, the present study de velops a three-dimensional analytical approach to determine the transm ission loss of circular expansion chambers with offset inlet and outle t ducts. The results obtained from the present approach. are compared with the classical one-dimensional predictions and the earlier multidi mensional works. (C) 1998 Academic Press Limited.