摘要: This study explores the physical interpretations of the instantaneous intensity, active intensity, and reactive intensity vectors in terms of energy transfer and wave properties in the nearfield of a general monochromatic sound fi... 展开 This study explores the physical interpretations of the instantaneous intensity, active intensity, and reactive intensity vectors in terms of energy transfer and wave properties in the nearfield of a general monochromatic sound field. The time dependent energy transfer is described by the instantaneous intensity, which contains contributions by the active intensity and the reactive intensity. The time independent intensity vectors are directly related to wave from properties. The active intensity vector is shown to be perpendicular to the resultant wave fronts and the reactive intensity is shown to point in the direction of decreasing pressure amplitude. Time dependent instantaneous intensity flux lines are drawn to show that in general the energy does not propagate with the resultant wave fronts. The speed of wave front propagation and the complex specific acoustic impedance are calculated from the nearfield measurements fo the time independent intensity vectors and energy densities. Five measured examples are presented which show that the location of energy sources, resonators, diffraction, and interference effects are clearly determined from analyses of the active intensity, reactive intensity, and potential energy, kinetic energy, phase speed, and complex specific acoustic impedance. Keywords: Acoustic intensity; Acoustic variables measurement; Acoustic waves; Acoustic wave effects; Acoustic wave intensity; Acoustic wave velocity; Nearfield acoustics. (JHD) 收起