Modeling Approach of Acoustic Streaming in Upper-Convected Maxwell Materials
Sprache des Vortragstitels:
Microelectronic Systems Symposium 2018
Sprache des Tagungstitel:
The term acoustic streaming describes the generation of a net flow due to the viscous attenuation of acoustic oscillations. It is a promising way to perform various tasks in microfluidics and gained increasing research interest in recent years. Solutions to such problems are often found using a perturbation approach, segregating the problem into a harmonic and a stationary subproblem; also numerical simulations are frequently performed in such a manner. Usually acoustic streaming problems are considered in Newtonian fluids, which solely show linear viscous flow behavior. This contribution expands the basic theory by introducing viscoelastic fluid behavior into the governing equations by considering so-called upper-convected Maxwell (UCM) materials; these fluids exhibit both viscous and elastic properties. The derivation of the modified equations using a perturbation approach is presented and numerical results obtained by finite element analysis are shown and compared to the Newtonian case. As a test problem a previously reported microfluidic pump design based on boundary-driven acoustic streaming is utilized. The presented theory can be further expanded by considering more refined material models like the Oldroyd-B or Giesekus model, which are more suitable for e.g. biological fluids.