Local and Focusing of Sound Field Based on Double Layer Cylindrical Structure

The acoustic focusing effect and the singular local effect of the bilayer columnar structure immersed in water were studied, and the relationship between the acoustic focusing frequency and the cylindrical structure parameters was explored. The results show that when the ultrasonic source is incident on the surface of the double columnar structure, the acoustic focusing effect occurs in the center of the cylindrical structure. The high and low cycle distributions of single-stage, dipole and multi-stage local sound fields occur at different frequencies, and the sound pressure in the surrounding environment is almost zero. This acoustic focusing effect results from the interference diffraction and the displacement eigenmode in the metal cylindrical structure.