An efficient strategy is developed for building suitable collision operators, to be used in a simplified version of the lattice gas Boltzmann equation. The resulting numerical scheme shown linearly stable. method applied computation flow channel containing periodic array obstacles.

An alternative simulation procedure is proposed for lattice hydrodynamics, based on the Boltzmann equation instead of microdynamical evolution. The averaging step, used by latter method to derive macroscopic quantities, suppressed, as well associated fluctuations. collision operator expressed in terms its linearized part, and condensed into a few parameters, which can be selected, independently particular rule, decrease viscosity much desired.

It is shown that the lattice Boltzmann equation (LBE) for a gas provides viable numerical method study of three-dimensional flows in complex geometries. Numerical results low Reynolds number random medium are reported. The Darcy's law recovered and preliminary estimation permeability presented.

Under certain conditions, the free surface of a conducting liquid subject to an electric field elongates into cone whose apex emits thin stationary jet that carries current. The structure flow in cone-to-jet transition region is investigated here, assuming size this small compared with any other length system where conical meniscus formed. local problem depends then on three non-dimensional parameters, two which are properties while third measures rate injected through meniscus. Numerical...

It is shown that the lattice Boltzmann equation deriving from Frisch-Hasslacher-Pomeau cellular automation, being free microscopic fluctuations, provides a new appealing tool to simulate realistic incompressible hydrodynamics. Numerical results pertaining two-dimensional flow past cylinder are reported and compared with numerical experimental data available in literature.

The penetration of a wetting liquid in the narrow gap between two vertical plates making small angle is analyzed framework lubrication approximation. At beginning process, rises independently at different distances from line intersection except region around this where effect gravity negligible. maximum height initially increases as cubic root time and attained point that reaches only after certain time. later times, motion confined to thin layer whose thickness decreases inverse evolution...

The β-assumed-p.d.f. approximation of Cook & Riley (1994) is tested as a subgrid model for the LES computation non-premixed turbulent reacting flows, in limit infinitely fast chemistry, two plane constant-density mixing layers with different degrees intermittency. Excellent results are obtained plane-averaged properties, such product mass fractions and relatively high powers temperature, even p.d.f. conserved scalar itself. In all these cases errors small enough to be useful practical...

The hydraulic jump appearing in the viscous laminar flow of a thin liquid layer over finite horizontal plate is studied using boundary-layer approximation for and around jump. position structure are determined by numerically solving resulting problem with boundary condition at edge that expresses matching shorter region where turns falls under action gravity. When Froude number ahead very large, much than extent layer, though still longer its depth. An asymptotic description inner such...

The generation of identical droplets controllable size in the micrometer range is a problem much interest owing to numerous technological applications such droplets. This work reports an investigation regime periodic emission from electrified oscillating meniscus liquid low viscosity and high electrical conductivity attached end capillary tube, which may be used produce more than ten times smaller diameter tube. To attain this microdripping regime, termed axial spray mode II by Juraschek...

An understanding of the processes enabling field-assisted evaporation ions from leaky dielectric liquids, i.e., liquids that are substantially less conductive than liquid metals, has historically been elusive in comparison to those conventional electrohydrodynamic emission modes such as cone-jet. While select ionic have shown yield nearly monodisperse beams molecular under certain conditions, dearth direct observation (visualization) and theoretical insight precluded a fundamental...

A combined experimental and numerical approach is used to extract information on the kinetics of ion evaporation from region high electric field around tip a Taylor cone neutral solvent propylene carbonate (PC) mixed with two ionic liquids. On side, surface liquid computed in absence by solving electrohydrodynamic problem this within framework leaky dielectric model. These computations justify approximate (2% max error) scaling E = β k for maximum surface, γ 1/2 ϵ 0 −2/3 ( K / Q ) 1/6 0.111...

A simple model of the transfer charge and ion evaporation in meniscus an ionic-liquid source working purely ionic regime is proposed on basis order-of-magnitude estimates which show that, this regime, (i) flow dominated by viscosity liquid affected very little mass flux accompanying evaporation, (ii) effect space around evaporating surface negligible current controlled finite electrical conductivity liquid. The predicts that a stationary polar undergoing nearly hydrostatic can exist only...

A numerical study is carried out of the injection a very viscous liquid small electrical conductivity at constant flow rate through an orifice in metallic plate under action electric field. The conditions which injected can form elongated meniscus with thin jet emanating from its tip are investigated by computing flow, field and transport charge leading region jet. stationary solution found only for values above certain minimum. At moderate applied field, this minimum decreases when or...

A relation between the electric current and flow rate of an electrospray operating in cone–jet mode is proposed for case a very small meniscus, long stationary jet, with important inertial effects. The finite size meniscus then affects bulk-to-surface transfer process, though still much larger than drops spray. result differs from square-root law which well-established large menisci or viscous flows.

The periodic generation of bubbles by injection a gas at constant flow rate through an orifice the bottom quiescent liquid high viscosity is investigated numerically. volume determined as function capillary number and Bond in absence inertial effects. Pairs coalesce vicinity when higher than critical value that depends on number, but final still follows well-known scaling law large numbers. Qualitative experimental visualizations are presented display sequences detachment coalescence computed

Electrostatic atomization of a liquid finite electrical conductivity in the so-called cone-jet regime relies on electric shear stresses that appear region surface when meniscus is subjected to an intense field. An order magnitude analysis used describe flow induced by these stresses, which drive into jet issues from tip and breaks droplets at some distance it. When dielectric constant large, extend cause depression sucks meniscus. The rate estimated shown represent approximately minimum can...

The growth of attached bubbles during the electrochemical evolution hydrogen at a horizontal cathode base quiescent, dilute aqueous solution is analysed using simple model process that includes Butler–Volmer reaction model, diffusion and migration electroactive species symmetry condition approximately accounts for presence periodically spaced on electrode surface. controlled bubble follows $t^{1/2}$ law when spacing large, departing slightly from it due to non-uniformity concentration...

Numerical computations and order-of-magnitude estimates are used to describe the stationary creeping flow of a jet Newtonian liquid with finite electrical conductivity that is injected into dielectric medium subject uniform electric field. The current carried by computed as function parameters problem, showing it increases rate intensity also depends on wetting conditions at injection orifice. Analysis transfer surface evolution under stresses act its leads scaling laws for other properties...