NUMERICAL SIMULATION OF NONLINEAR SOUND PROPAGATION FROM A FINITE EXPONENTIAL HORN USING IMMERSED BOUNDARY METHOD

Nonlinear propagation of finite-amplitude sound waves both inside and outside a finite exponential horn with a circular cross section, which is driven by a vibrating piston, are investigated in this paper. The finite-amplitude vibration of the piston is simplified as a velocity boundary condition. Euler equations are numerically solved on a Cartesian grid in the cylindrical coordinates to study the nonlinear sound propagation. The high-order, low-dispersion, and low-dissipation finite difference schemes are employed. An immersed boundary method is applied to deal with the curved boundary of the exponential horn. Nonlinear perfectly matched layer method is applied to get rid of reflected waves from the opening boundary. Results show the sound radiation field of the exponential horn. Nonlinear distortion of the sound pressure at the horn mouth is observed in the numerical simulation. The proposed approach can also be applied to simulate nonlinear sound propagation in a horn of arbitrary profile.