摘要
Conception of normal modes of vibrations is generalized to finite-amplitude sound fields in enclosures, by taking into account of the nonlinear effects. This includes the solution of the wave equation in the form of nonlinear partial differential equations for the sound fields.This is made possible with a deep insight of the standing wav character of the normal modes.The nonlinarity does not change in any way the standing wav character, and ouly modifies the motions at different points of the standing wave. Thus only the time-derivatives of the modifications should be preserved in the wav equations, which become, then, soluble. In this way, the trite-amplitude normal functions are derived for the first thoe, containing basic terms, the same normal functions as in linear acoustics, and their modilications. Besides, timeindepent terms echt in the normal functions of noalinear acoustics, representing the radiation pressure in the finilte-amplitude sound fields.
Conception of normal modes of vibrations is generalized to finite-amplitude sound fields in enclosures, by taking into account of the nonlinear effects. This includes the solution of the wave equation in the form of nonlinear partial differential equations for the sound fields.This is made possible with a deep insight of the standing wav character of the normal modes.The nonlinarity does not change in any way the standing wav character, and ouly modifies the motions at different points of the standing wave. Thus only the time-derivatives of the modifications should be preserved in the wav equations, which become, then, soluble. In this way, the trite-amplitude normal functions are derived for the first thoe, containing basic terms, the same normal functions as in linear acoustics, and their modilications. Besides, timeindepent terms echt in the normal functions of noalinear acoustics, representing the radiation pressure in the finilte-amplitude sound fields.
