Numerical and analytical studies on viscous air damping in laterally oscillating microcomb structures are discussed in this work. Previous investigators modeled this type of flow field using Couette and Stokes flow models. The numerical simulation results demonstrate that the flow is much more complex and quite different from the Couette or Stokes flow. The pumping and sucking motions at the edges of the oscillating electrode create a fluid brake. This fluid brake retards the horizontal movement of the flow and generates a strong vortex in the region between the oscillating electrode and the base material, which has not been reported before. The deceleration of the fluid also increases the velocity gradient on the surfaces of the oscillating electrode, which gives rise to a higher damping. The numerically predicted damping is about 2.8 times larger than that predicted by the Stokes flow model.
International Journal of Heat and Mass Transfer 46(4), pp.695-704