Parallel plates shear-wave transducers for the characterization of viscous and viscoelastic fluids

We present a novel sensor design for viscosity measurements using shear-waves, which opens up opportunities for rheological applications in the low kHz range. Two electrodynamic in-plane plate resonators are aligned in parallel and separated by a defined gap filled with the fluid sample. The lower plate is actuated, generating a shear-wave in the viscous or viscoelastic fluid. The response on the upper plate, which is coupled to the lower plate with the viscous fluid in between, is recorded in a frequency range where resonances are observed. The coupling of both resonators increases with viscosity, allowing a, for resonator sensors unprecedented, high viscosity measurement range measured up to 17.1 Pa.s. In this contribution we will introduce the sensor concept, present an analytical model and discuss the results of measurements made with various fluids.