Development of a shear ultrasonic spectroscopy technique for the evaluation of viscoelastic fluid properties: Theory and experimental validation.

•New algorithm to convert the experimental shear reflection coefficient in viscosity.•New ultrasonic method to measure the viscosity-frequency spectrum of liquid samples.•Three reference samples were tested. The experimental results agree with the model proposed.•The results for the Non-Newtonian sample tested are in agreement with Carreau rheological model.•A resonant quarter wavelength-layer enhanced measurement sensitivity.