Investigation of acoustic streaming patterns around oscillating sharp edges

Abstract

Oscillating sharp edges have been employed to achieve rapid and homogeneous mixing in microchannels using acoustic streaming. Here we use a perturbation approach to study the flow around oscillating sharp edges in a microchannel. This work extends prior experimental studies to numerically characterize the effect of various parameters on the acoustically induced flow. Our numerical results match well with the experimental results. We investigated multiple device parameters such as the tip angle, oscillation amplitude, and channel dimensions. Our results indicate that, due to the inherent nonlinearity of acoustic streaming, the channel dimensions could significantly impact the flow patterns and device performance.

A reliable and programmable acoustofluidic pump powered by oscillating sharp-edge structures

“…These simulation results indicate pumping behavior and are also in good agreement with the experimental results we acquired. It should also be noted that in the simulations a flow singularity was observed at the sharp-edges, similar to that observed in our previous study, 45 which is indicated by the maximum velocity at the sharp edge tips. This velocity increases with the mesh refinement and our solution is strictly valid only outside the boundary layer.…”

Numerical study of acoustophoretic motion of particles in a PDMS microchannel driven by surface acoustic waves

“…It is this second component which is generally referred to as the streaming motion . 2 Following our recent model, 19 we employ Nyborg’s perturbation technique 20 in which fluid velocity, density, and pressure are assumed to have the following form…”

Comparing methods for the modelling of boundary-driven streaming in acoustofluidic devices

“…It is the different rotationality of the RSF inside and immediately outside the boundary layer that forms the inner and outer streaming vortices and forces the former in the thin acoustic boundary layer with a size of approximately δ v in devices where h ≫ δ v . This understanding of the mechanism could also be extended to better understand (and hence design) boundary-driven streaming flows in diverse types of acoustofluidic channels, including those with non-flat fluid channel surfaces (Lei et al 2014a, b;Nama et al 2014;Ovchinnikov et al 2014). However, although the RSM has shown high precision for modelling both acoustic streaming patterns and magnitudes of streaming velocities, the tiny mesh element required to resolve the acoustic and streaming fields in the near-boundary region suggests it may be a very computationally demanding method and thus not suitable for 3D modelling of most practical acoustofluidic manipulating devices.…”