Fluid Dynamics of an Electrowetting-on-dielectrics Tube Oscillator

We study the fluid dynamics of polar high-k fluids immersed in non-polar insulating fluids, excited by electrowetting-on-dielectric (EWOD) forces inside a tube with pressure compensation channels. The fluids are set in motion using the electrowetting effect resulting in a pressure difference inside the tube. A model of the pressure field for various viscosities of the surrounding fluid is obtained by finite element analysis of the Navier-Stokes equation. From the time dependent pressure response and the associated viscous damping, a correlation with the fluid's dynamic viscosity is obtained. In the next step, we study the pressure evolution after driving the polar fluid in one direction and stopping it rapidly at the edge of the driving electrode. The decay time of the pressure induced height difference inside the compensation channels can also be related to the surrounding non-polar fluid's viscosity. Subsequently, a cheap alternative fabrication process of an EWOD stack will be shown and used to build a tube oscillator simulated in the steps before.