Hydrodynamic interactions between air bubbles and particles have wide applications in multiphase separation and reaction processes. In the present work, we explore the fundamental mechanism of such complex processes by studying the collision of a single bubble with a fixed solid particle inside a Hele-Shaw cell. Physical experiments show that an air bubble either splits or slides around the par...

Compressible large-eddy simulations of turbulent flow over a wall-mounted hump with active flow control are performed and compared to previous experiments. We consider a range of Mach numbers from 0.1 to 0.6. Control is applied just before the natural separation point via steady suction and zero-net mass flux oscillatory forcing. Compared with the baseline flow, control shortens the separation ...

To be applicable to complex aerodynamic flows at realistic Reynolds numbers, large eddy simulation (LES) must be combined with a model for the inner part of the boundary layer. Aerodynamic flows are, in general, very sensitive to the location of boundary layer transition. While traditional LES can predict the transition location and process accurately, existing wall-modeled LES approaches can n...

A computational study is conducted to explore the effect of synthetic jet orientation on boundary layer separation control. A six-to-one aspect-ratio rectangular slot is chosen in the current study and streamwise and spanwise orientations of this slot are analyzed. In the first part of this study, the interaction of the jet with an attached laminar boundary layer for both slot configurations is...

A microfluidic system with a wide surface area per unit volume has the potential for use in highly efficient chemical synthesis, separation, and extraction. In the case of efficient water/oil separation and material extraction, it becomes important to form a stable two-layer laminar flow interface. Previously, we developed a silicon/glass microfluidic reactor, in which microchannel inner walls ...

Alexander Vilenkin Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155, USA Topological defects can naturally be formed soon after bubble nucleation in the open inflation scenario. The defects are not completely diluted away by the subsequent period of inflation in the bubble interior and can produce observable large-scale microwave background anisot...

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Here we present a continuous molecule separation/concentration system using flowing microbubbles as carriers. Microbubbles continuously generated at the microchannel confluence are able to capture target substances dissolved in the liquid phase, and these bubble carriers are concentrated by continuously removing liquid phase from the stream to achieve the continuous molecule separation. In the ...

Lin & Pauley [2] studied unsteady boundary-layer separation from an Eppler 387 airfoil at low Reynolds number numerically and compared their results with wind tunnel measurements. They found unsteady large-scale structure might control the lowReynolds-number separation bubble reattachment with smallscale turbulence playing a secondary role [4]. Drela [5], Drela & Giles[6] used a fully coupled n...