The utilization of distributions to describe active absorption by means of the first-order equations of acoustics

First-order distribution equations for acoustic pressure and velocity are employed to explain forced and rapid modifications of acoustic fields, such as active sound absorption. The equations for the conservation of mass and energy in the presence of acoustic pressure and velocity discontinuities are differentiated with respect to the acoustic pressure and velocity distributions in order to obtain distributions proportional to the jumps of acoustic pressure and velocity. Secondary acoustic sources are shown to be equivalent to linear combinations of pressure and velocity discontinuities and are interpreted physically as monopole and dipole sources of flow and power, respectively.