Direct simulations are used to study turbulence and mixing in Holmboe waves. Previous results showing that mixing in Holmboe waves is comparable to that found in the better-known Kelvin–Helmholtz (KH) billows are extended to cover a range of stratification levels. Mixing efficiency is discussed in detail, as are effective diffusivities of buoyancy and momentum. Entrainment rates are compared wi...

Secondary flow plays a critical function in a microchannel, such as a micromixer, because it can enhance heat and mass transfer. However, there is no experimental method to visualize the secondary flow and the associated mixing pattern in a microchannel because of difficulties in high-resolution, non-invasive, cross-sectional imaging. Here, we simultaneously imaged and quantified the secondary ...

We exploited the viscoelasticity of biocompatible dilute polymeric solutions, namely, dilute poly(ethylene oxide) solutions, to significantly enhance mixing in microfluidic devices at a very small Reynolds number, i.e., Re approximately 0.023, but large Peclet and elasticity numbers. With an abrupt contraction microgeometry (8:1 contraction ratio), two different dilute poly(ethylene oxide) solu...

A finite element model has been used in order to study the mixing process of species in a 100-microm-wide zigzag microchannel integrating a "Y" inlet junction. The distribution of the concentration was obtained by solving successively the Navier-Stokes equation and the diffusion-convection equation in the steady state form. Because of the large range of Reynolds numbers studied (1 < Re < 800), ...

Mixing efficiency at low Reynolds numbers can be enhanced by exploiting hydrodynamic instabilities that induce heterogeneity and disorder in the flow. The unstable displacement of fluids with different viscosities, or viscous fingering, provides a powerful mechanism to increase fluid-fluid interfacial area and enhance mixing. Here we describe the dissipative structure of miscible viscous finger...

The paper focuses on the data collected from the mixing of shear thinning non-Newtonian fluids in a cylindrical tank by a Rushton turbine. The data presented are obtained by using Computational Fluid Dynamics (CFD) simulation of fluid flow field in the entire tank volume. The CFD validation data for this study is reported in the research article 'Numerical investigation of hydrodynamic behavior...

The development and application of a new simultaneous injectioneffective mixing flow analysis (SIEMA) is described. The manifold is based on one syringe pump with a two-way solenoid valve, a set of holding coils and three-way solenoid valves, two multiport connectors, a mixing coil and a detector. The system is compact and is controlled by a laptop computer. Some analytical features of SIEMA ar...

The process of mixing by tides interacting with topography involves several stages. First some fraction of the energy contained in the barotropic tide must be converted into baroclinic energy, through the generation of internal tides and turbulent boundary layers. Secondly, the energy in the internal tides must be transmitted into smaller vertical wavelengths, thereby increasing the vertical sh...