The compact acoustic liquid sensor based on the circumferential modes of a cylindrical shell

Abstract Liquid sensing is achieved by using a resonant cylindrical shell. The sensing mechanism is based on the fact that the localized circumferential waves confined around the cylindrical shell interact intensively with the liquid sample inside the shell, with the resonant transmission of the cylindrical shell being strongly dependent on the acoustic properties of the liquid in the shell, especially the density of the liquid. Numerical simulations and experimental measurements show that the transmission dip varies with the concentration of a sodium iodide (NaI) and water mixture in the shell. The advantages of a liquid sensor based on the circumferential modes of a cylindrical shell are numerous. For example, a minimal liquid sample is required, the cylindrical shell is disposable, and the sensor is compatible with other microfluidic components, thereby allowing the liquid sensor to be integrated with lab-on-a-chip devices for various microfluidic sensing applications.