Acoustic transmission through asymmetric grating structures made of cylinders

Based on the multiple scattering theory, we have developed a highly efficient numerical method to calculate the acoustic transmission and reflection coefficients for complex grating structures made of cylinders. This method can provide the detailed information for each independent diffraction order, which is particularly useful in studying the exotic transmission behavior through spatially asymmetric gratings. Our numerical results manifest that, in general, such gratings produce asymmetric transmission if only the frequency is high enough to create the nonzero order diffraction. An intuitive and valid scheme is further proposed to suppress the transmission along one of the incident directions, producing an almost unidirectional acoustic transmission. Such kind of unidirectional transmission could be very useful in designing acoustic rectifying devices. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4709730]