Edge Transport and Self-Assembly of Passive Objects in a Chiral Active Fluid*

Topological edge flow and dissipationless odd viscosity are two remarkable features of chiral active fluids composed of active spinners. These features can significantly influence the dynamics of suspended passive particles and the interactions between the particles. By computer simulations, we investigate the transport phenomenon of anisotropic passive objects and the self-assembly behavior of passive spherical particles in the active spinner fluid. It is found that in confined systems, nonspherical passive objects can stably cling to boundary walls and are unidirectionally and robustly transported by edge flow of spinners. Furthermore, in an unconfined system, passive spherical particles are able to form stable clusters that spontaneously and unidirectionally rotate as a whole. In these phenomena, strong particle-wall and interparticle effective attractions play a vital role, which originate from spinner-mediated depletion-like interactions and can be largely enhanced by odd viscosity of spinner fluids. Our results thus provide new insight into the robust transport of cargoes and the nonequilibrium self-assembly of passive intruders.

A Brief Technical Note on the Onset of Convection in a Horizontal Nanofluid Layer of Finite Depth via Wakif-Galerkin Weighted Residuals Technique (WGWRT)

The onset of convection in a horizontal nanofluid layer of finite depth is a subject that can never be over-emphasized as it plays a significant role in controlling the transport phenomenon within a nanofluidic medium. This body of knowledge led to a doubtful report in 2014 by Nield and Kuznetsov concerning some obtained equations and established results. However, the accuracy of the thermal stability characteristics is strongly dependent on the used model as well as the employed methodological procedure. In this report, countable models are suggested as a better improvement of the aforementioned analysis. Either mathematical or technical point of view, it is worth concluding that the approximate analytical results elaborated by Nield and Kuznetsov can be improved properly by using the models presented herein.

Numerical modelling of sediment transport in a channel bend with floating units

<p>Floating units/booms are used to trap or guide floating debris in watercourses. In a relatively shallow depth, these floats could affect the velocity distribution, sediment transport and channel bed deformation.  A three-dimensional non-hydrostatic numerical modelling was performed in a 180 degree channel bend with floats to see the effects in flow distribution and bed deformation as a conceptual study. Different configurations of the floats were simulated. The results showed that the flow velocity increased and deposition decreased at the inner bank of the bend. Use of floating units could be studied to alter sediment deposition pattern and sediment transport phenomenon in watercourses.</p>

Relationship between the formation of flow paths and elution behavior with water flow through the soil column

<p>The transport phenomenon of pollutants in soil is complicated because of the formation of the flow path in soil. In this study, the relationship between the flow path in the soil and the elution behavior of various components was evaluated by the column tests with different filling methods to change the flow path in the column. The flow path in the column was visualized by using potassium iodide aqueous solution and X-ray CT. Our result shows that the elution behavior of the easily eluted components was not significantly affected by the flow path in the column. In addition, the cation more eluted when the flow path spread throughout the column than when the flow path was intensive. This suggests that eluted components may be affected by anions in soil. From these results, it was found that the elution behavior of components is influenced by the flow path in the column and some were not, and when it was influenced, the degree of influence is different depending on the components.</p>