Acoustic Streaming in a Microchannel Cross Section
Application ID: 17087
Recent advances in the fabrication of microfluidic systems require handling of live cells and other micro particles as well as mixing. All this can, for example, be achieved using acoustic radiation forces and the viscous drag from the streaming flow.
Streaming: Due to the nonlinear terms in the Navier-Stokes equations, harmonic perturbation of the flow will lead to a net time-averaged flow called acoustic streaming. Acoustic streaming is a second order (nonlinear) acoustic effect. The effect can be simulated in two ways: either by direct simulation solving the nonlinear Navier-Stokes equations, or as shown here by separation of time scales.
Radiation Force: Due to nonlinear terms in the governing equations momentum can be transferred from an acoustic field to particles. This results in a net force acting on the particles – the acoustic radiation force.
The trajectory of particles in devices will be governed by the balance between the viscous drag force (from the streaming flow) and the acoustic radiation force. This model shows how to include and model both using COMSOL Multiphysics.
The model presented here is based on the papers:
P. B. Muller and H. Bruus, "Numerical study of thermoviscous effects in ultrasound-induced acoustic streaming in microchannels," Phys. Rev. E 90, 043016 (2014).
J. T. Karlsen and H. Bruus, “Forces acting on a small particle in an acoustical field in a thermoviscous fluid,” Phys. Rev. E 92, 043010 (2015).
This model example illustrates applications of this type that would nominally be built using the following products:
however, additional products may be required to completely define and model it. Furthermore, this example may also be defined and modeled using components from the following product combinations:
- COMSOL Multiphysics® and
- Acoustics Module and
- Particle Tracing Module and
- either the Battery Design Module, CFD Module, Chemical Reaction Engineering Module, Corrosion Module, Electrochemistry Module, Electrodeposition Module, Fuel Cell & Electrolyzer Module, Microfluidics Module, Polymer Flow Module, Porous Media Flow Module, or Subsurface Flow Module
The combination of COMSOL® products required to model your application depends on several factors and may include boundary conditions, material properties, physics interfaces, and part libraries. Particular functionality may be common to several products. To determine the right combination of products for your modeling needs, review the Specification Chart and make use of a free evaluation license. The COMSOL Sales and Support teams are available for answering any questions you may have regarding this.