Acoustic band gaps in three-dimensional CsCl-type periodic liquid composites

Acoustic band gaps (ABGs) in three-dimensional (3D) CsCl-type acoustic crystals consisting of water scatterers embedded in mercury hosts have been studied. By using the super cell method based on the plane-wave expansion, we present three configurations formed by inserting an additional water object (either a sphere or a cube) into the center of each unit cell of a simple cubic (SC) structure. Numerical results show that the CsCl-type acoustic crystals can obtain larger absolute ABGs than the original SC structure, even the body-centered-cubic (BCC) structure. We also compare our results with that of 3D solid composites and find that the ABGs in liquid composites are insensitive to the shapes of scatterers as those in the solid composites.