A U-shaped wire for viscosity and mass density sensing

• A resonant viscosity and mass density sensor based on an oscillating U-shaped tungsten wire is presented.
• The device was designed to feature low cross-sensitivity to temperature.
• A comprehensive closed form model considering the fundamental structural and fluid mechanics is derived.
• The model relates input-signals to output-signals in dependence of the sample fluid's mass density and viscosity.
• Measurements showing the sensor's performance and the validity of the presented model are discussed in detail.

A resonant sensor for a fluid's viscosity and mass density, employing an out-of-plane vibrating U-shaped tungsten wire is presented. The motivation for such a design is based on four major aspects, which are: operation in the low kilohertz range, circular cross-section of the resonator, electrodynamic actuation and read-out by means of Lorentz forces and low cross-sensitivity of the device's resonance frequency to temperature. The setup is described in detail, an analytical model is presented and results from experiments using acetone–isopropanol and DI-water–glycerol solutions are discussed to show the sensor's performance.