Fugacity coefficients of dilute aqueous solutions of six species belonging to normal fluids (CO2, C2H4, C2H6, C3H8, n-C4H10, i-C4H10) as well as functional groups CH3 and CH2 have been evaluated from ambient conditions (298 K, 0.1 MPa) to high temperatures (up to 2000 K) and water densities (up to 1500 kg m−3). The basis of the approach is a correlation developed for the function, A12∞=V2∞/κTRT, that

A novel method for the determination of chemical equilibrium for detonation products under extreme pressure and temperature conditions is presented. A stochastic algorithm based on Particle Swarm Optimization (PSO) technique is developed for calculating the minimum Gibbs free energy of the system and thereby estimating the equilibrium composition of the product species. The aforementioned PSO algorithm

In this paper, a two-dimensional lattice-gas model is applied to study the stability and lattice distortion of sI clathrate hydrates of ethylene. Two levels of approximation are considered for the lateral interactions between the adsorbed molecules. By using Monte Carlo simulations, adsorption isotherm (coverage of the cavities as a function of the chemical potential), degree of deformation of the

In the present paper, an improved multiphase weakly compressible smoothed particle hydrodynamics model for balancing the accuracy and stability of the long‐term simulations is proposed to model the forced liquid sloshing in a tank. The governing equations of the multiphase flow are discretized by considering the density discontinuity over the interface. To suppress the pressure oscillation, a previous

In the last decade, the interest towards fluids characterized by a complex rheology has increased in the scientific community. Physicochemical, rheological and fluid mechanical approaches are adopted to characterize the peculiarities of non-Newtonian fluids. These fluids show remarkable properties that can be exploited to improve remediation techniques or optimize industrial operations. While the existence

The paper describes the longitudinal dispersion of passive tracer materials released into an incompressible viscous fluid, flowing through a channel with walls having first-order reaction. Its model is based on a steady advection–diffusion equation with Dirichlet’s and mixed boundary conditions, and whose solution represents the concentration of the tracers in different downstream stations. For imposing

We observed green optical emission from an atmospheric‐pressure N2/O2 plasma jet. The green optical emission was composed of a line emission at λ  = 557.71 ± 0.03 nm and a broadband component at 530 ≤ λ  ≤ 560 nm. The line emission was assigned to the 1D −1S forbidden transition of atomic oxygen, whereas the broadband emission was due to the formation of O(1S )N2 excimer. We measured the absolute densities

We study the bifurcations of the large scale jets in the turbulent regime of a forced shear flow using direct numerical simulations of the Navier-Stokes equations. The bifurcations are seen in the probability density function (PDF) of the largest scale mode with the control parameter being the Reynolds number based on the friction coefficient denoted as Rh. As one increases Rh in the turbulent regime

Numerical simulations are carried out to study the spectra and statistics in chemically reacting compressible homogeneous isotropic turbulence at turbulent Mach number Mt from 0.1 to 1.0 and at Taylor Reynolds number Reλ from 54 to 103 with solenoidal forcing. A single-step irreversible Arrhenius type chemical reaction is implemented to evaluate the influence of chemical reaction on spectra and flow

We present an experimental study of resonant generation of superharmonic internal waves as a result of interaction between horizontally propagating vertical internal wave modes m and n at frequency ω0 in a uniformly stratified finite-depth fluid. Thorpe (J. Fluid Mech. 24 , 737, 1966) has shown theoretically that modes m and n at frequency ω0 and mode-p=|m−n| at frequency 2ω0 are in triadic resonance

In this work, we investigate flow topology modifications produced by a swarm of large surfactant-laden droplets released in a turbulent channel flow. Droplets have same density and viscosity of the carrier fluid, so that only surface tension effects are considered. We run one single-phase flow simulation at Reτ=ρuτh/μ=300, and ten droplet-laden simulations at the same Reτ with a constant volume fraction

Ring-shaped deposits can be often found after a droplet evaporates on a substrate. If the fluid in the droplet is a pure liquid and its contact line remains pinned during the process, the mechanism behind such ring-shaped deposition is the well-known coffee-stain effect. However, adding small amounts of salt to such a droplet can change the internal flow dramatically and {consequently} change the deposition

The diffuse-interface model (DIM) is a widely used tool for modeling fluid phenomena involving interfaces – such as, for example, sessile drops (liquid drops on a solid substrate, surrounded by saturated vapor) and liquid ridges (two-dimensional sessile drops). In this work, it is proved that, surprisingly, the DIM does not admit solutions describing static liquid ridges. If, however, the vapor-to-liquid

The success of direct laser-driven inertial confinement fusion (ICF) relies critically on the efficient coupling of laser light to plasma. At ignition scale, the absolute stimulated Raman scattering (SRS) instability can severely inhibit this coupling by redirecting and strongly depleting laser light. This article describes a new dynamic saturation regime of the absolute SRS instability near one quarter

We focus on the self-propelled motion of an oil/aqueous droplet within an aqueous/oil phase, which originates from an interfacial chemical reaction of surfactant. Droplet motion has been explained by mathematical models; however, these models require the assumption that the chemical reaction increases the interfacial tension. On the other hand, several experimental reports have demonstrated self-propelled

The homogenization approach to wave propagation through saturated porous media is extended in order to include compressibility of the interstitial fluid and the existence of several connected pore components which may or not percolate. The necessary theoretical developments are summarized and the Christoffel equation whose solutions provide the wave velocities is presented. Some analytical developments

In a 2D liquid crystal, each topological defect has a topological charge and a characteristic orientation, and hence can be regarded as an oriented particle. Theories predict that the trajectories of annihilating defects depend on their relative orientation. Recently, these predictions have been tested in experiments on smectic-C films. Those experiments find curved trajectories that are similar to

We study the large deviations of time-integrated observables of Markov diffusions that have perfectly reflecting boundaries. We discuss how the standard spectral approach to dynamical large deviations must be modified to account for such boundaries by imposing zero-current conditions, leading to Neumann or Robin boundary conditions, and how these conditions affect the driven process, which describes

We study periodic arrays of impurities that , embedded in 2D crystalline membranes. These arrays provide a simple elastic model of shape memory. As the size of each dilational impurity increases (or the relative cost of bending to stretching decreases), it becomes energetically favorable for each of the M impurities to buckle up or down into the third dimension, thus allowing for of order 2M metastable

Formation of consensus, in binary yes/no type of voting, is a well defined process. However, even in presence of clear incentives, the dynamics involved can be incredibly complex. Specifically, formations of large groups of similarly opinionated individuals could create a condition of `support-bubbles’ or spontaneous polarization that renders consensus virtually unattainable (e.g., the question of

We present a to provide an alternative to the Langevin equation by identifying the (no stochastic component) microforce 𝐅k,BP acting on a nonequilibrium Brownian particle (BP) in its kth microstate 𝔪k. (The prefix micro refers to microstate quantities and carry a suffix k.) The deterministic new equation is easier to solve using basic calculus. Being oblivious to the second law, 𝐅k,BP does always

Wall-bounded turbulent channel flows up to Reτ=640 are simulated with multi-relaxation-time (MRT) lattice Boltzmann models. In order to perform direct numerical simulations and to resolve the wall boundary layer, a successive refinement procedure is developed to capture the rapid variation of the flow properties in the near-wall region. In the present implementation, three levels of grids are adopted

We present a detailed numerical investigation on the salient features of flow over an SAE reference body with several backlight angles representing a standard notchback geometry using Scale Resolving Simulations (SRS) such as the SBES and the SDES. A grid evaluation study is performed for the SAE Notchback geometry with 20° backlight angle with a Reynolds number (Re) of 6.57 × 105 based on the height

We present a method for speeding up equilibrium simulations of liquid crystals for two related models that are degenerate with respect to defects: the Ericksen model and the uniaxially constrained Landau-de Gennes model. The degeneracy induces a non-linear/non-smooth coupling between the two order parameters in both models that makes the discrete problems very stiff to solve. The technique described

An algorithm for automated fitting of the effective electron temperature from a planar Langmuir probe I – V trace taken in a plasma with multiple Maxwellian electron populations is developed through MATLAB coding. The code automatically finds a fitting range suitable for analyzing the temperatures of each of the electron populations. The algorithm is used to analyze I – V traces from both the Institute

In the present work, creepage discharge characteristics, i.e. amplitudes, phases, and repetitiveness, and surface charge dynamic behaviors under a 20 kHz high-frequency sinusoidal waveform high-voltage electrical stress were captured in a discharge chamber with temperature and humidity control. The results showed that the creepage discharges mostly occurred in the positive half phase, whose maximum

Volume translation (VT) has been widely utilized to improve the liquid density (or volume) prediction by cubic equation of state (CEOS). Previous VT-models do not fully exploit the potential of distance function and there is still a room for improving the prediction accuracy of saturated and single-phase liquid densities by CEOS. In this study, we propose an improved volume translated Soave-Redlich-Kwong

Salts of the basic amino acid l-arginine are potential co-promoters and blending components for the conventional solvents used in carbon dioxide-based separations. This study defines the contribution of arginine salts to equilibrium carbon dioxide absorption at co-promoter concentrations (less than 1 M) and high pressure. Experimentally determined carbon dioxide loadings in aqueous potassium and sodium

Simultaneous description of critical point, vapor pressure and liquid density with an equation of state has been a hot research topic. In this work, the possibilities and limitations of the Cubic Plus Association equation of state for describing these properties of associating fluids have been studied. First a procedure is developed to determine the energy and co-volume parameters by converting the

CO2 sequestration in saline aquifers is considered to be a promising method for climate mitigation. Studies of the subsurface flow mechanisms of CO2–brine are important for evaluation of sequestration potential and security. However, this process is complicated by the intrinsic heterogeneity of reservoir rocks. The main objective of this study was to identify CO2 distribution and saturation related

Droplet size distribution during ultrasonic atomization was investigated by laser diffraction based on two phenomena—capillary waves and cavitation. The former was visually illustrated using the photographic method, and the latter was examined by the potassium iodide decomposition rate test and Particle Image Velocimetry technique. This study also analyzed the effects of operating ultrasonic parameters

In order to understand the energy transfer mechanism and the coupling relationship between the interface evaporation and thermocapillary convection at low vapor pressures, a series of precise temperature measurements were conducted in a water-filled annular pool with radial temperature gradient. The initial depth of water in the annular pool is 10 mm and the temperature difference between the inner

Upon cavitation cloud collapse an omnidirectional shock wave is emitted. It then travels through the flow field, causing a cascade of events resulting in erosion, noise, vibration and the cavitation shedding process. Despite that the accumulated data points evidently to the presence of the shock waves, the direct measurements hardly exist - and even then, they are very expensive and time consuming

A model for the wave motion of an internal wave in the presence of current in the case of intermediate long wave approximation is studied. The lower layer is considerably deeper, with a higher density than the upper layer. The flat surface approximation is assumed. The fluids are incompressible and inviscid. The model equations are obtained from the Hamiltonian formulation of the dynamics in the presence

Abstract Particle image velocimetry is an established technique for optical flow measurement, in which the local fluid velocity is derived from the motion of passive tracer particles. This motion is typically computed by a cross-correlation of small interrogation windows from subsequent image frames. Masking of objects within a velocimetry image is required to avoid correlation bias from interrogation

Abstract A novel moving frame-of-reference brightness-based laser-induced fluorescence (MFoR-BBLIF) method was developed and demonstrated in downwards co-current air–water annular flows. The method was applied to study the downstream development of individual disturbance waves in flows over a range of conditions (ReL = 276–1321, ReG = 39,500–79,000). In this method, the optical measurement system,

Foam has shown promising characteristics for soil remediation, especially as a blocking agent. In very permeable porous media, high groundwater velocity reduces the efficiency of in situ remediation by decreasing the contact time with contaminants. To use foam to reduce water velocity, this paper investigates its properties in very permeable porous media (> 4.10−10 m2). Alpha olefin sulfonate foam

To study the droplet entrainment mechanisms in liquid nitrogen (LN2) and vaporous nitrogen (VN2) countercurrent flow, simulation on three fields comprised of the liquid, the vapor, and the droplet phase was implemented for the horizontal segregated flow based on the Eulerian-Eulerian mathematical framework in ANSYS Fluent®. The droplet entrainment model was adopted to determine the droplet entrainment

Current mathematical models and numerical codes used for thermal–hydraulic analyses of forced-flow superconducting cables used in the fusion technology, such as, e.g. Cable-in-Conduit Conductors (CICCs), are typically 1D. They demand reliable constitutive expressions for the transverse momentum, energy and optionally also mass transport processes occurring between different parallel conductor components

The potential application of electrical capacitance volume tomography (ECVT) to the liquid nitrogen-vaporous nitrogen two-phase flow measurement is evaluated by numerical experiment. The Landweber iteration is taken as the inversion algorithm which derives the reconstructed images. Eight types of ECVT sensor structures are tested and the accuracy of the reconstructed images is compared to evaluate

Superconducting DC energy pipeline is an energy channel that simultaneously transmits electrical energy as well as the liquid fuel. It improves the efficiency of energy transmission and reduces the overall cost by cooling high-temperature superconducting DC cables with the low-temperature liquid fuel, such as liquid hydrogen, liquefied shale gas, and liquified natural gas (LNG). In order to properly

The one-dimensional implementation of the Delayed Equilibrium Model (DEM) is known as a relatively simple yet accurate approach for prediction of critical mass flow rate, pressure and void fraction distributions for two-phase water transonic flows in ducts of variable geometry. However, the direct application of DEM equipped with original saturation index evolution law and Lockhart-Martinelli approach