We reexamine the theoretical efficiency of superleak second-sound transducers, following Liu and Stern, by assuming continuity of the chemical potential across the transducer membrane. Taking the low-frequency limit we obtain a result for the generation process which is independent of the shape of the backplate region. Our result agrees with that of Johnson for a cylindrical backplate region. We also consider the detection process, including the contribution of superflow through the superleak pores, to the membrane effective mass. A form of reciprocity is obtained between the generation and detection processes. 1983 The American Physical Society.
