Relaxation and propagation of pulses in fluids (Q1096497)

Mathematical bases for the diagnostics of relaxing fluids in probing by sound pulses based on recording these pulse shapes are developed. Analysis of the change in the pulse shape makes it possible to establish the type of relaxation and to determine its parameters: the relaxation time, the dispersion jump in the velocity, and others. To calculate the pulse shape, the creep kernels for the three main types of relaxation in fluids are found: Kneser relaxation, resonance relaxation, and relaxation associated with diffusive transfer. The shape of the pulse (initially square) near the front is calculated for these types of relaxation.