Multi-directional Sound Reduction by Slitted Sonic Crystal

Abstract

Sonic crystals (SC) are the periodic arrangements of solid objects, i.e., cylinders, blocks, spheres, etc., in fluid media. SC are known for noise attenuation over a certain range of frequency. The direction of incident noise on the SC affects the sound transmission loss as well as the bandgap. In this work, SC are designed in such a way that changing the position of noise source will not affect the sound transmission loss and the bandgap as much as in the conventional SC. The effect of slitted scatterers is investigated on the bandgap and the sound transmission loss. The structure is subjected to a planar wave coming from the different directions and results are compared with each other. Finite element simulation is used to calculate the sound transmission loss and the bandgap in SC with and without rectangular slits. Results show that the slitted SC work more effectively with multi-directional noise source than the conventional SC.