The Experts below are selected from a list of 52437 Experts worldwide ranked by ideXlab platform

Mercier Matthieu - One of the best experts on this subject based on the ideXlab platform.

  • Particles, Drops, and Bubbles Moving Across Sharp Interfaces and Stratified Layers
    'Annual Reviews', 2020
    Co-Authors: Magnaudet Jacques, Mercier Matthieu
    Abstract:

    International audienceRigid or deformable bodies moving through continuously stratified layers or across sharp interfaces are involved in a wide variety of geophysical and engineering applications, with both miscible and immiscible Fluids. In most cases, the body moves while pulling a column of Fluid, in which density and possibly viscosity differ from those of the neighboring Fluid. The presence of this column usually increases the Fluid Resistance to the relative body motion, frequently slowing down its settling or rise in a dramatic manner. This column also exhibits specific dynamics that depend on the nature of the Fluids and on the various physical parameters of the system, especially the strength of the density/viscosity stratification and the relative magnitude of inertia and viscous effects. In the miscible case, as stratification increases, the wake becomes dominated by the presence of a downstream jet, which may undergo a specific instability. In immiscible Fluids, the viscosity contrast combined with capillary effects may lead to strikingly different evolutions of the column , including pinch-off followed by the formation of a drop that remains attached to the body, or a massive fragmentation phenomenon. This review discusses the flow organization and its consequences on the body motion under a wide range of conditions, as well as potentialities and limitations of available models aimed at predicting the body and column dynamics

  • Particles, Drops, and Bubbles Moving Across Sharp Interfaces and Stratified Layers
    'Annual Reviews', 2020
    Co-Authors: Magnaudet Jacques, Mercier Matthieu
    Abstract:

    Rigid or deformable bodies moving through continuously stratified layers or across sharp interfaces are involved in a wide variety of geophysical and engineering applications, with both miscible and immiscible Fluids. In most cases, the body moves while pulling a column of Fluid, in which density and possibly viscosity differ from those of the neighboring Fluid. The presence of this column usually increases the Fluid Resistance to the relative body motion, frequently slowing down its settling or rise in a dramatic manner. This column also exhibits specific dynamics that depend on the nature of the Fluids and on the various physical parameters of the system, especially the strength of the density/viscosity stratification and the relative magnitude of inertia and viscous effects. In the miscible case, as stratification increases, the wake becomes dominated by the presence of a downstream jet, which may undergo a specific instability. In immiscible Fluids, the viscosity contrast combined with capillary effects may lead to strikingly different evolutions of the column, including pinch-off followed by the formation of a drop that remains attached to the body, or a massive fragmentation phenomenon. This review discusses the flow organization and its consequences on the body motion under a wide range of conditions, as well as potentialities and limitations of available models aimed at predicting the body and column dynamics

Magnaudet Jacques - One of the best experts on this subject based on the ideXlab platform.

  • Particles, Drops, and Bubbles Moving Across Sharp Interfaces and Stratified Layers
    'Annual Reviews', 2020
    Co-Authors: Magnaudet Jacques, Mercier Matthieu
    Abstract:

    International audienceRigid or deformable bodies moving through continuously stratified layers or across sharp interfaces are involved in a wide variety of geophysical and engineering applications, with both miscible and immiscible Fluids. In most cases, the body moves while pulling a column of Fluid, in which density and possibly viscosity differ from those of the neighboring Fluid. The presence of this column usually increases the Fluid Resistance to the relative body motion, frequently slowing down its settling or rise in a dramatic manner. This column also exhibits specific dynamics that depend on the nature of the Fluids and on the various physical parameters of the system, especially the strength of the density/viscosity stratification and the relative magnitude of inertia and viscous effects. In the miscible case, as stratification increases, the wake becomes dominated by the presence of a downstream jet, which may undergo a specific instability. In immiscible Fluids, the viscosity contrast combined with capillary effects may lead to strikingly different evolutions of the column , including pinch-off followed by the formation of a drop that remains attached to the body, or a massive fragmentation phenomenon. This review discusses the flow organization and its consequences on the body motion under a wide range of conditions, as well as potentialities and limitations of available models aimed at predicting the body and column dynamics

  • Particles, Drops, and Bubbles Moving Across Sharp Interfaces and Stratified Layers
    'Annual Reviews', 2020
    Co-Authors: Magnaudet Jacques, Mercier Matthieu
    Abstract:

    Rigid or deformable bodies moving through continuously stratified layers or across sharp interfaces are involved in a wide variety of geophysical and engineering applications, with both miscible and immiscible Fluids. In most cases, the body moves while pulling a column of Fluid, in which density and possibly viscosity differ from those of the neighboring Fluid. The presence of this column usually increases the Fluid Resistance to the relative body motion, frequently slowing down its settling or rise in a dramatic manner. This column also exhibits specific dynamics that depend on the nature of the Fluids and on the various physical parameters of the system, especially the strength of the density/viscosity stratification and the relative magnitude of inertia and viscous effects. In the miscible case, as stratification increases, the wake becomes dominated by the presence of a downstream jet, which may undergo a specific instability. In immiscible Fluids, the viscosity contrast combined with capillary effects may lead to strikingly different evolutions of the column, including pinch-off followed by the formation of a drop that remains attached to the body, or a massive fragmentation phenomenon. This review discusses the flow organization and its consequences on the body motion under a wide range of conditions, as well as potentialities and limitations of available models aimed at predicting the body and column dynamics

B. C. Khoo - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of Stokes flow in microchannels with superhydrophobic surfaces containing a periodic array of micro-grooves
    Microfluidics and Nanofluidics, 2008
    Co-Authors: B. C. Khoo
    Abstract:

    Superhydrophobic surfaces have been demonstrated to be capable of reducing Fluid Resistance in micro- and nanoFluidic applications. The objective of this paper is to present analytical solutions for the Stokes flow through microchannels employing superhydrophobic surfaces with alternating micro-grooves and ribs. Results are presented for both cases where the micro-grooves are aligned parallel and perpendicular to the flow direction. The effects of patterning the grooves on one or both channel walls are also analyzed. The reduction in Fluid Resistance has been quantified in terms of a dimensionless effective slip length, which is found to increase monotonically with the shear-free fraction and the periodic extent of each groove–rib combination normalized by the channel half-height. Asymptotic relationships have been derived for the normalized effective slip length corresponding to large and small limiting values of the shear-free fraction and the normalized groove–rib period. A detailed comparison has been made between transverse and longitudinal grooves, patterned on one or both channel walls, to assess their effectiveness in terms of enhancing the effective slip length. These comparisons have been carried out for small and large limiting values, as well as finite values of the shear-free fraction and normalized groove–rib period. Results for the normalized effective slip length corresponding to transverse and longitudinal grooves are further applied to model the Stokes flow through microchannels employing superhydrophobic surfaces containing a periodic array of micro-grooves inclined at an angle to the direction of the applied pressure gradient. Results are presented for the normalized effective slip lengths parallel to the direction of the applied pressure gradient and the normalized cross flow rate perpendicular to the direction of the applied pressure gradient.

Lei Wang - One of the best experts on this subject based on the ideXlab platform.

  • directional droplet actuation and Fluid Resistance reduction performance on the bio inspired shark fin like superhydrophobic surface
    Journal of The Taiwan Institute of Chemical Engineers, 2019
    Co-Authors: Qier An, Bo Zhang, Woochul Yang, Hongbin Zhao, Jinshu Wang, Lei Wang
    Abstract:

    Abstract The tunable of Fluid transport on solid surface plays a significant role for self-cleaning and drug-saving fields. It effectively prevents the corrosion and declines the Fluid Resistance induced by the rushing water and accumulated microorganisms on the hull surface. To more effectively combat these problems, herein, we provide a new strategy, a superhydrophobic shark-fin-like bionic surface. Anisotropic characteristic of this novel structure lead to the different de-pinning force in the opposite direction for the water droplet. The superhydrophobicity of the shark-fin-like embossment is from the "air layer" formed by the ZnO nano-structure. This novel composited surface can effectively realize the directional droplet-actuation and Fluid-Resistance reduction performance. Droplets and Fluid will move more easily along the special direction on the shark-fin-like surface. Moreover, the substrate material is flexible and easy to mass production. We believe that this work will give a significant scientific insight to self-cleaning surface and hull design.

Xingzhong Zhao - One of the best experts on this subject based on the ideXlab platform.

  • a valve based microFluidic device for on chip single cell treatments
    Electrophoresis, 2019
    Co-Authors: Zixiang Wang, Qianfang Meng, Qingquan Liao, Xingzhong Zhao
    Abstract:

    : Assays toward single-cell analysis have attracted the attention in biological and biomedical researches to reveal cellular mechanisms as well as heterogeneity. Yet nowadays microFluidic devices for single-cell analysis have several drawbacks: some would cause cell damage due to the hydraulic forces directly acting on cells, while others could not implement biological assays since they could not immobilize cells while manipulating the reagents at the same time. In this work, we presented a two-layer pneumatic valve-based platform to implement cell immobilization and treatment on-chip simultaneously, and cells after treatment could be collected non-destructively for further analysis. Target cells could be encapsulated in sodium alginate droplets which solidified into hydrogel when reacted with Ca2+ . The size of hydrogel beads could be precisely controlled by modulating flow rates of continuous/disperse phases. While regulating Fluid Resistance between the main channel and passages by the integrated pneumatic valves, on-chip capture and release of hydrogel beads was implemented. As a proof of concept for on-chip single-cell treatments, we showed cellular live/dead staining based on our devices. This method would have potential in single cell manipulation for biochemical cellular assays.