  Most measurement methods based on ultrasound, such as sound velocity,
absorption or flow measurement systems, require that the acoustic wave
propagation is linear. In many cases, linear wave propagation is assumed due to
small signal amplitudes or verified, for example, by analysing the received
signal spectra for the generation of harmonic frequency components. In this
contribution, we present an approach to quantify occurrence of non-linear
effects of acoustic wave propagation in ultrasonic measurement systems based on
the evaluation of the acoustic Reynolds number. One parameter required for the
determination of the acoustic Reynolds number is the particle velocity of the
acoustic wave, which is not trivially obtained in most measurement systems. We
thus present a model-based approach to estimate the particle velocity of an
acoustic wave by identifying a Mason model from electrical impedance
measurements of a given transducer. The Mason model is then used to determine
the transducer's velocity output for a given electrical signal, allowing for an
evaluation of the acoustic Reynolds number for different target media.
