Inverse determination of liquid viscosity by means of the Bleustein–Gulyaev wave

The Bleustein–Gulyaev (B–G) wave in piezoelectric materials of orthorhombic mm2 crystal class is reported to be a promising candidate for application to liquid sensing. In this work we present a rigorous quantitative investigation of the propagation of B–G wave in mm2 crystals in contact with a viscous liquid. An inversion algorithm is formulated to determine the liquid viscosity from the wave speed and attenuation data. Numerical results and discussions are given for potassium niobate (KNbO3). The inversion results demonstrate that the liquid viscosity can be successfully determined from wave propagation characteristics.