Sound radiation from a concave or a convex dome in a semi-infinite tube

Abstract

A previous study [H. Suzuki and J. Tichy, J. Acoust. Soc. Am. 69, 41–49 (1981)] showed that a concave or a convex dome in an infinite baffle has radiation characteristics that are different from those of the flat piston. These results indicated that a concave or a convex dome in a lossless tube may also have different radiation characteristics than a similarly mounted flat piston. This problem was investigated using the same method as the previous studies. The results show that the farfield sound pressure response rises by about 0.5 to 0.7 dB in the frequency range ka = 2.2 to 2.8 for both concave and convex domes having the height-to-radius (a) ratio of 0.5 to 1.0. As expected, the radiation resistance increases by about 13% to 17% over the radiation resistance in the low-frequency region. The radiation reactance is very small at low frequencies but becomes comparable to the resistance at frequencies above ka = 2.5. The reactance is always negative below the cutoff frequency.