Intensity streamlines and vorticity streamlines in three-dimensional sound fields

The properties of intensity streamlines and vorticity streamlines are discussed in this paper. It is found that the properties in three-dimensional sound fields are different from the properties in two-dimensional sound fields. The integral behavior of intensity streamlines is that the beginning and the end are attached to a sound source surface or that the beginning is on the sound source surface and the end extends into the infinite. For the vorticity streamlines, the integral behavior is that it is a closed curve or that the beginning and the end are attached to the sound source surface. Three examples are given for intensity and vorticity streamlines. (C) 2000 Acoustical Society of America. [S0001-4966(00)05801-X].