Session 5pPA: Physical Acoustics 5pPA10. Experimental investigation of a characteristic shock formation distance in finite-amplitude noise propagation

Unlike initially sinusoidal waveforms, the definition of the "shock formation distance" for noise is complicated by the fact that not all shocks form at the same rate. Examination of the concept of a "characteristic" shock formation distance for noise raises some questions: Is there some generalization of the shock formation distance for sinusoidal signals that can be applied to noise? If so, is it inversely proportional to amplitude and frequency, as the pure tone distance is? In this study, initially sinusoidal, narrowband, and broadband noise data have been acquired using 3.18 mm microphones flush mounted along the walls of an anechoically terminated plane-wave tube. The behavior of the time derivative statistics for the sine-wave tests has been used to guide formulation of a statistical definition of a characteristic shock formation distance for initially Gaussian noise.