Acoustic Force Density Acting on Inhomogeneous Fluids in Acoustic Fields.
We present a theory for the acoustic force density acting on inhomogeneous fluids in acoustic fields on time scales that are slow compared to the acoustic oscillation period. The acoustic force density depends on gradients in the density and compressibility of the fluid. For microfluidic systems, the theory predicts a relocation of the inhomogeneities into stable field-dependent configurations, which are qualitatively different from the horizontally layered configurations due to gravity. Experimental validation is obtained by confocal imaging of aqueous solutions in a glass-silicon microchip.
Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark.
Jonas T
JT
Karlsen
Department of Biomedical Engineering, Lund University, Ole Römers väg 3, 22363 Lund, Sweden.
Per
P
Augustsson
Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark.
Henrik
H
Bruus