Analyzing the transition pressure and viscosity limit of a hydroelastic microfluidic oscillator

We analyze the transition of a hydroelastic microfluidic oscillator from steady laminar flow to oscillatory flow. Results show that the transition pressure is influenced by both the fluid viscosity and the device geometry, which can be explained through the negative differential resistance effects. Due to the deflection of the elastic diaphragm, the flow resistance increases with the driving pressure (P-0), and this increase is more significant at higher viscosities. At the critical transition point, further increase of P-0 will cause a reduction in the flow rate and trigger the oscillation. This provides an alternative point of view to the occurrence of flow induced vibrations. We also demonstrate that through optimization of the design, the current device is capable of working in high-viscosity environments of up to 89 cP. (C) 2014 AIP Publishing LLC.