Low frequency vibration induced streaming in a Hele-Shaw cell

M Costalonga (1) , Philippe Brunet (1) , H Peerhossaini (2)

1 MSC (UMR_7057) - Matière et Systèmes Complexes
2 LIED (UMR_8236) - Laboratoire Interdisciplinaire des Energies de Demain

When an acoustic wave propagates in a fluid, it can generate a second order flow whose characteristic time is much longer than the period of thewave.Within a range of frequency between ten and several hundred Hz, a relatively simple and versatile way to generate streaming flow is to put a vibrating object in the fluid. The flow develops vortices in the viscous boundary layer located in the vicinity of the source of vibrations, leading in turn to an outer irrotational streaming called Rayleigh streaming. Because the flow originates from non-linear time-irreversible terms of the Navier-Stokes equation, this phenomenon can be used to generate efficient mixing at low Reynolds number, for instance in confined geometries. Here, we report on an experimental study of such streaming flow induced by a vibrating beam in a Hele-Shaw cell of 2 mm span using long exposure flowvisualization and particle-image velocimetry measurements. Our study focuses especially on the effects of forcing frequency and amplitude on flow dynamics. It is shown that some features of this flow can be predicted by simple scaling arguments and that this vibration-induced streaming facilitates the generation of vortices.

Domains: Physics [physics]; Mechanics [physics]; Fluid mechanics [physics.class-ph]; Physics [physics]; Physics [physics]; Fluid Dynamics [physics.flu-dyn]; Nonlinear Sciences [physics]; Pattern Formation and Solitons [nlin.PS]; Physics [physics]; Condensed Matter [cond-mat]; Soft Condensed Matter [cond-mat.soft]

M Costalonga, Philippe Brunet, H Peerhossaini. Low frequency vibration induced streaming in a Hele-Shaw cell. Physics of Fluids, 2015, ⟨10.1063/1.4905031⟩. ⟨hal-01297164⟩