Ion distribution and velocity profiles for electro-osmotic flow in a 3.49 nm wide slit channel with a surface charge density of -0.285 C/m(2) are studied using molecular dynamics simulations. Simulation results indicate that the concentration of the co-ion exceeds that of the counterion in the region 0.53 nm away from the channel wall, and the electro-osmotic flow is in the opposite direction t...

The development of secondary flow along a curved channel is fundamental phenomenon occurring in wide range engineering applications, including turbomachinery, aerospace, heating, ventilation, air conditioning, etc. underlying physics about end-wall flows has been well-documented the open literature, while interaction between and side-wall boundary layer, which critical to aerothermal performanc...

Instability of a viscous incompressible flow in a channel with wavy walls is investigated theoretically, numerically and experimentally. Linear stability analysis shows that appropriately chosen wall waviness leads to flow destabilization at surprisingly low Reynolds numbers. The unstable mode of disturbances forms a vortex array, which travels downstream. The remarkable feature is that the mos...

We consider the possibility of adding a stage to a dilution refrigerator to provide additional cooling by "filtering out" hot atoms. Three methods are considered: (1) effusion, where holes having diameters larger than a mean-free path allow atoms to pass through easily; (2) particle waveguidelike motion using very narrow channels that greatly restrict the quantum states of the atoms in a channe...

A large number of molecules are usually required to model atomic walls in molecular dynamics simulations. A virtual-wall model is proposed in this study to describe fluid-wall molecular interactions, for reducing the computational time. The infinite repetition of unit cell structures within the atomic wall causes the periodicity of the force acting on a fluid molecule from the wall molecules. T...

Algebraic explicit wall models covering the entire inner region of turbulent boundary layer are proposed to reduce computational effort for large eddy simulation wall-bounded flows. The formulas given in closed forms with either logarithmic- or power-function-based laws wall, allowing straightforward evaluation friction velocity on near grids independent their locations layer. performance is de...

A numerical hybrid method for analyzing the wireless channel of Multiple-Input Multiple-Output (MIMO) communication system is proposed by combining of the method of moments (MoM) and the finite difference time domain (FDTD) method. The proposed method is capable of investigating a more practical MIMO wireless channel than the conventional methods, and CPU time is much less than that of the FDTD...

We generate and study electroosmotic shear flow in microchannels. By chemically or electrically modifying the surface potential of the channel walls a shear flow component with controllable velocity gradient can be added to the electroosmotic flow caused by double layer effects at the channel walls. Chemical modification is obtained by treating the channel wall with a cationic polymer. In case ...

We examined the formation of a multiply curved meniscus inside rectangular nanochannels, whose width ranges from 50 to 800 nm at a constant height of 200 nm. When the channel width is smaller than approximately 400 nm under partial wetting conditions, a distinct multi-curvature meniscus was observed at the advancing front with an edge disjoined from the wall. In contrast, a typical pre-wetting ...