Multilayer Water Research Articles

Hyperbolic decomposition for hydrostatic approximation of free surface flow problems

The article is devoted to the description of a new method of numerical solution for hydrostatic approximation of incompressible hydrodynamic problems with free surfaces and variable density. This technique develops a model of multilayer shallow water, taking into account the mass and momentum exchange between the layers.

Quantitative determination of the bound water in Bazhenov shales

The article presents the first results of determining the content of different types of bound water by hygrometric method — adsorption isotherm method — for non-extracted air-dry samples of Bazhenov formation rocks. The obtained water sorption isotherms for the studied samples have a well-expressed s-shape, which allows to determine the maximum possible amount of bound water of different types in them — mono-, poly — and capillary condensation and to draw an important conclusion about the hydrophilicity of the Bazhenov formation deposits. According to the form of sorption isotherms, the amount of bound water and the proximity of mineral compositions, nine samples were combined into 4 different groups, the remaining samples were considered individually. A correlation between the pore water content and the content of mono- and multilayer water was found.

Utilization of legume flours in wafer sheets

AbstractIn this study, it was aimed to analyze the impacts of replacement of 20% of wheat flour by lentil, chickpea, or bean flours on batter rheology as well as hardness, weight loss, sorption characteristics, and color of the wafer sheets. All formulations showed shear thinning behavior obeying power law. Lentil flour‐containing formula gave the highest flow behavior index and the lowest consistency coefficient value. Hardness of wafer sheets increased when legume flours were used. Increase in hardness value was less when chickpea flour was used as compared with the other legume flours. It was observed that upon baking, legume flour‐added samples had lower weight loss values. Usage of chickpea flour resulted in the lowest weight loss. Sorption results implied localized sorption indicating multilayer water molecules showing similar properties to liquid water. Wafers containing legume flours were not significantly different than the control wafer in terms of monolayer moisture content, K and C values of Gugenheim, Anderson and de Boer (GAB) model. The color of chickpea flour‐containing wafer was the closest to that of control sample. Overall, wafer sheets prepared by replacement of 20% wheat flour by chickpea flour was agreed to be the best in terms of the analyzed parameters.

MRT-Lattice Boltzmann Model for Multilayer Shallow Water Flow

The objectives of this study are to introduce a multiple-relaxation-time (MRT) lattice Boltzmann model (LBM) to simulate multilayer shallow water flows and to introduce graphics processing unit (GPU) computing to accelerate the lattice Boltzmann model. Using multiple relaxation times in the lattice Boltzmann model has an advantage of handling very low kinematic viscosity without causing a stability problem in the shallow water equations. This study develops a multilayer MRT-LBM to solve the multilayer Saint-Venant equations to obtain horizontal flow velocities in various depths. In the multilayer MRT-LBM, vertical kinematic viscosity forcing is the key term to couple adjacent layers. We implemented the multilayer MRT-LBM to a GPU-based high-performance computing (HPC) architecture. The multilayer MRT-LBM was verified by analytical solutions for cases of wind-driven, density-driven, and combined circulations with non-uniform bathymetry. The results show good speedup and scalability for large problems. Numerical solutions compared well to the analytical solutions. The multilayer MRT-LBM is promising for simulating lateral and vertical distributions of the horizontal velocities in shallow water flow.

A dynamic multilayer shallow water model for polydisperse sedimentation

A multilayer shallow water approach for the approximate description of polydisperse sedimentation in a viscous fluid is presented. The fluid is assumed to carry finely dispersed solid particles that belong to a finite number of species that differ in density and size. These species segregate and form areas of different composition. In addition, the settling of particles influences the motion of the ambient fluid. A distinct feature of the new approach is the particular definition of the average velocity of the mixture. It takes into account the densities of the solid particles and the fluid and allows us to recover the global mass conservation and linear momentum balance laws of the mixture. This definition motivates a modification of the Masliyah–Lockett–Bassoon (MLB) settling velocities of each species. The multilayer shallow water model allows one to determine the spatial distribution of the solid particles, the velocity field, and the evolution of the free surface of the mixture. The final model can be written as a multilayer model with variable density where the unknowns are the average velocities and concentrations in each layer, the transfer terms across each interface, and the total mass. An explicit formula of the transfer terms leads to a reduced form of the system. Finally, an explicit bound of the minimum and maximum eigenvalues of the transport matrix of the system is utilized to design a Harten–Lax–van Leer (HLL)-type path-conservative numerical method. Numerical simulations illustrate the coupled polydisperse sedimentation and flow fields in various scenarios, including sedimentation in a type of basin that is used in practice in mining industry and in a basin whose bottom topography gives rise to recirculations of the fluid and high solids concentrations.

A New Multilayer Nonhydrostatic Formulation for Surface Water Waves

Wang, G.; Liang, Q.; Zheng, J., and Wan, P., 2019. A new multilayer nonhydrostatic formulation for surface water waves. Journal of Coastal Research, 35(3), 693–710. Coconut Creek (Florida), ISSN 0749-0208.This work presents a new multilayer nonhydrostatic formulation for surface water waves. The new governing equations define velocities and pressure at an arbitrary location of a vertical layer and only contain spatial derivatives of maximum second order. Stoke-type Fourier and shoaling analyses are carried out to scrutinize the mathematical properties of the new formulation, subsequently optimizing the representative interface and the location to define variables in each layer to improve model accuracy. Following the analysis, the one-layer model exhibits accurate linear and nonlinear characteristics up to kd = π, demonstrating similar solution accuracy to the existing second-order Boussinesq-type models. The two-layer model with optimized coefficients can maintain its linear and nonlinear accuracy up to kd = 4π, which boasts of better solution accuracy a larger application range than most existing fourth-order Boussinesq model and two-layer Boussinesq models. The three-layer model presents accurate linear and nonlinear characteristics up to kd = 10π, effectively removing any shallow water limitation. The current multilayer nonhydrostatic water wave model does not predefine the vertical flow structures, and more accurate vertical velocity distributions can be obtained by considering the velocity profiles in coefficient optimization.

Simulation and performance analysis of concentrating photovoltaic/thermal collector (CPV/T) with three-sided thermal insulation based on coupled optothermal model

The present paper is focused on drawing a high performance modeling and computation of a low concentrating collector combined into a Photovoltaic/Thermal system. A 3-D computational model based on 3D-4Rays technique and volume finite method is developed. The collector consists of a trough parabolic concentrator of a 20× concentration rate and two axis tracking system. The absorber is composed of a square duct in which Triple-junction PV cells are connected in series into its lower surface and a three-sided insulated multi-layer water channel, which acts as a cooling system introducing heat recovery capability.A steady pressure-driven laminar flow of a Newtonian fluid is assumed with constant properties inside water microchannel. This coupled model is initially used to simulate and analyze the temperature distributions within the PV cells, and then the thermal and electrical behavior of the proposed system. The results of the coupled model are compared with the analytical model in terms of thermal and electrical performances, such as PV cell temperature, electrical efficiency, and outlet water temperature. In addition, the impact of non-uniform illumination on the PV solar cells is also investigated. The results of the analysis indicated that a discontinuity of the thermal conductivity along the absorber tube duct, post shading and non-uniformities of PV cells temperature distributions causes a reduction in thermal efficiency of slightly more than 6% while significantly effecting the overall electrical performance.

DFT Simulation on Interaction of H2O Molecules with ZnS and Cu-Activated Surfaces

The adsorption of isolated, monolayer, and multilayer water molecules on ZnS and Cu-activated surfaces was studied by density functional theory (DFT) calculations. Adsorption energy calculation and adsorption configuration analysis of water molecules suggest that the ZnS surface is more hydrophilic than the Cu-activated surface. It is found that both metal–O interaction and OH···S hydrogen-bond interaction on the ZnS surface are greater than those on the Cu-activated surface. In addition, the difference in the adsorption of water molecules is related to the difference in the surface structure of ZnS and Cu-activated surfaces. Density-of-state (DOS) calculation suggests that Cu-activated surface has stronger π-bond and covalency than ZnS surface. The DOS calculation also suggests that the electronic interaction of H and S atoms on the ZnS surface is stronger than that on the Cu-activated surface. Dynamics simulations using density functional based tight binding method suggest that the water molecules close...

Analysis of the Magnetic Field in the Cavity of Multi-Layer Winding Electromagnetic Water Processor

Based on the online electromagnetic scale suppression dynamic simulation table designed by our team, the magnetic induction intensity in the cavity of single- and multi-layer winding electromagnetic water processor is simulated and analyzed by using numerical simulation. The relationship between the magnetic induction intensity of the inner cavity and the number of turns of the coil, wire diameter, and inner diameter and the effect of the segment on the intensity of the magnetic induction in the inner cavity are analyzed. According to the Bio–Savarts law, the formula for calculating the magnetic induction intensity in the cavity of multi-layer winding electromagnetic water processor is derived. Moreover, the structural parameters of the processor are determined based on the simulation results of the Maxwell equations. According to the simulation results, we make a new multi-layer winding electromagnetic water processor, which will be used on the online electromagnetic scale suppression dynamic simulation table in the future.

Manufacture of Multi-Layered High Efficiency Water Treatment Filter

Manufacture of Multi-Layered High Efficiency Water Treatment Filter

Enhanced thermal conductance at the graphene-water interface based on functionalized alkane chains.

Highly efficient thermal transport between graphene and water is crucial in applications such as microscopic heat dissipation, solar steam generation, sea-water desalination, and thermally conductive composites. However, a practical approach for enhancing thermal transport across graphene–water interfaces is lacking. We propose an effective and universal method to improve thermal-transport properties at the interface between multilayer graphene and water by a factor of ∼4 by grafting functionalized groups onto graphene. The most improved interfacial thermal conductance was 121.0 ± 11.4 MW m−2 K−1. This design is compatible with industrial processes. We also undertook molecular-level analyses to unveil the underlying mechanism for heat-transport enhancement. This study could provide new approaches for engineering heat transport across two-dimensional materials and water interfaces.

Resistance-based analysis of limiting interfaces in multilayer water splitting photocathodes by impedance spectroscopy

Electrochemical impedance spectroscopy is used to determine the potential-dependent resistances in multilayer photocathodes for water splitting. Limitations in the devices can thereby be identified and improvements proposed and investigated.

Dynamic Water Nanotube Cluster Stabilized in Molecule-Based Hydrophilic Nanoporous Crystal with New Organic Spacers

Abstract This study investigated the structure and phase transition behaviour of a dynamic water nanotube cluster (WNT) confined within hydrophilic 1D nanochannels. We demonstrated that the WNT has a three-layered hydrate structure stabilized by hydrogen bonds with carboxylate groups in the outer channel walls. Moreover, it exhibits a pre-melting state that was attributed to the presence of metastable structures. Interestingly, the dynamic WNT structure was maintained even in the melting state because the multi-layered water cluster was stabilized in the hydrophilic nanoporous channel. To our knowledge, such a dynamic three-layered WNT structure is unique and rare because most WNTs are regarded as disordered water clusters. Therefore, we constructed another dynamic WNT using [RuIII(H2bim)3]3+ (H2bim = 2,2′-biimidazole) and a new organic spacer, 1,3,5-triazine-2,4,6-tricarboxylate (TATC3−). The dynamic WNT cluster has been identified for the crystal structure and heat properties.

Energy–water and GHG nexus: A South African water industry case

Abstract Water and energy are resources that are dependent on each other. Water is needed for the production of energy for fuel extraction, cooling power plants, and processing of fossil fuels. In water cycles, energy is needed for pumping, treatment and distribution of water and wastewater to and from customers. In South Africa (SA), the energy used in the water industry is generated mostly from fossil fuels, which has a significant negative impact on the environment. This research reviews a representative subset of the SA water industry to evaluate energy efficiency and harmful gas emissions optimisation potential. The first component of this study involves a review of the current energy efficiency potential in water distribution systems in SA. On the basis of a literature review, three technologies/practices were identified as being imperative in optimising water utilities in SA. The second part of this study involves the implementation of some performance indicators that illustrate the interdependence of water loss, energy consumption and CO2, NOX and SOX emissions. These indicators are used to compare a few possible mitigation scenarios involving water loss reduction and increasing the system's energy efficiency. The third component of research is developing a novel multi-layered structural water distribution system model by incorporating 29 metrics extracted from the literature reviewed. Analysis of this model is then conducted using a MULTI-MOORA (Multi-Objective Optimization by Ratio Analysis) technique accompanied by a Triangular Fuzzy Number set. The aim of this was to assist water utility managers to identify the most influential performance indicators for attaining the nexus objectives.

Nanoscale Structure and Dynamics of Water on Pt and Cu Surfaces from MD Simulations.

The interaction of liquid water with Pt(111) is investigated with classical molecular dynamics (MD) simulations, where the forces are determined using the third-generation charge optimized many-body (COMB3) interatomic potential. In cases of sub-monolayer water coverage, the parameterized empirical potential predicts experimentally observed and energetically favorable √37 and √39 reconstructed water structures with "575757" di-interstitial defects. At both sub-monolayer and multilayer water coverages, the structure of the first wetting layer of liquid water on Pt(111) exhibits a characteristic distribution where the molecules form two distinct buckled layers as a result of the interplay between water-metal adsorption and water-water hydrogen bonds. The dynamic spreading rate of water nanodroplets on large Pt surfaces (>200 nm2) characterized by molecular kinetic spreading theory is an order of magnitude slower than the molecular kinetic rate of the same droplet on close-packed Cu surfaces due to variation in molecular distributions at the water-metal interface. These nanoscale MD simulation predictions using the COMB3 interatomic potential demonstrate the capability of capturing both many-body interactions between H2O and Pt or Cu and hydrogen bonding in liquid water.

Available Potential Energy in Density Coordinates

AbstractThe vertically integrated potential energy of an incompressible stratified fluid formulated in density coordinates can be simply written as a weighted vertical sum of the squares of the vertical displacements of density surfaces, a general expression valid for arbitrary displacements. The sum of this form of potential energy and kinetic energy is then a conserved quantity for the multilayer shallow water model. The formulation in density coordinates is a natural one to find the Lorenz reference state of available potential energy (APE). We describe the method to compute the APE of an ocean state and provide two applications. The first is the classical double-gyre, wind-driven circulation simulated by a shallow water model at high resolution. We show that the eddy kinetic and eddy potential energies are localized in regions of large gradients of mean APE. These large gradients surround an APE minimum found between the two gyres. The second is the time-mean World Ocean Circulation reconstructed from hydrography (World Ocean Atlas) and reference velocities at 1000 db from the Argo float program to obtain an absolute circulation. The total available potential energy exceeds the total mean kinetic energy of the World Ocean by three orders of magnitude, pointing out the very small Burger number of the circulation. The Gulf Stream, the Kuroshio, the Agulhas retroflection, and the confluence regions are four examples that confirm the shallow water model results that large gradients of mean available potential energy can be used as predictors for the presence of high eddy kinetic energy (obtained here from satellite altimetry).

A Multilayer Surface Temperature, Surface Albedo and Water Vapor Product of Greenland from MODIS.

A multilayer, daily ice-surface temperature (IST)-albedo-water vapor product of Greenland, extending from March 2000 through December 2016, has been developed using standard MODerate-resolution Imaging Spectroradiometer (MODIS) data products from the Terra satellite. To meet the needs of the ice sheet modeling community, this new Earth Science Data Record (ESDR) is provided in a polar stereographic projection in NetCDF format, and includes the existing standard MODIS Collection-6.1 IST and derived melt maps, and Collection 6 snow albedo and water vapor maps, along with ancillary data, and is provided at a spatial resolution of ~0.78 km. This ESDR enables relationships between IST, surface melt, albedo and water vapor to be evaluated easily. We show examples of the components of the ESDR and describe some uses of the ESDR such as for comparison with skin temperature, albedo and water vapor output from Modern Era Retrospective-analysis for Research and Applications, Version 2 (MERRA-2). Additionally we show validation of the MODIS IST using in situ and aircraft data, and validation of MERRA-2 skin temperature maps using MODIS IST and in situ data. The ESDR has been assigned a DOI and will be available through the National Snow and Ice Data Center by the summer of 2018.

Multilayer shallow water models with locally variable number of layers and semi-implicit time discretization

We propose an extension of the discretization approaches for multilayer shallow water models, aimed at making them more flexible and efficient for realistic applications to coastal flows. A novel discretization approach is proposed, in which the number of vertical layers and their distribution are allowed to change in different regions of the computational domain. Furthermore, semi-implicit schemes are employed for the time discretization, leading to a significant efficiency improvement for subcritical regimes. We show that, in the typical regimes in which the application of multilayer shallow water models is justified, the resulting discretization does not introduce any major spurious feature and allows again to reduce substantially the computational cost in areas with complex bathymetry. As an example of the potential of the proposed technique, an application to a sediment transport problem is presented, showing a remarkable improvement with respect to standard discretization approaches.

A Fractal Model for Gas–Water Relative Permeability in Inorganic Shale with Nanoscale Pores

A reliable gas–water relative permeability model in shale is extremely important for the accurate numerical simulation of gas–water two-phase flow (e.g., fracturing fluid flowback) in gas-shale reservoirs, which has important implication for the economic development of gas-shale reservoir. A gas–water relative permeability model in inorganic shale with nanoscale pores at laboratory condition and reservoir condition was proposed based on the fractal scaling theory and modified non-slip boundary of continuity equation in the nanotube. The model not only considers the gas slippage in the entire Knudsen regime, multilayer sticking (near-wall high-viscosity water) and the quantified thickness of water film, but also combines the real gas effect and stress dependence effect. The presented model has been validated by various experiments data of sandstone with microscale pores and bulk shale with nanoscale pores. The results show that: (1) The Knudsen diffusion and slippage effects enhance the gas relative permeability dramatically; however, it is not obviously affected at high pressure. (2) The multilayer sticking effect and water film should not be neglected: the multilayer sticking would reduce the water relative permeability as well as slightly decrease gas relative permeability, and the film flow has a negative impact on both of the gas and water relative permeability. (3) The increased fractal dimension for pore size distribution or tortuosity would increase gas relative permeability but decrease the water relative permeability for a given saturation; however, the effect on relative permeability is not that notable. (4) The real gas effect is beneficial for the gas relative permeability, and the influence is considerable when the pressure is high enough and when the nanopores of bulk shale are mostly with smaller size. For the stress dependence, not like the intrinsic permeability, none of the gas or water relative permeability is sensitive to the net pressure and it can be ignored completely.

Enhanced thermal transport across multilayer graphene and water by interlayer functionalization

Graphene has attracted enormous attention due to its extraordinary physical properties, which have potential for increasing the thermal conductivity of nanocomposites or nanofluids, and the thermal resistance between graphene and the surrounding matrices arises as an important issue. In this paper, the thermal transport at the graphene-water interface is investigated by molecular dynamics simulations. The interfacial thermal resistance decreases with the graphene layer number. Interlayer functionalization by oxygen atoms is applied to tune the interfacial thermal resistance. A peak thermal resistance reduction of nearly 50% is generated with the oxygen ratio of only 0.5% for two-layer graphene. Based on the analyses of vibrational density of states, it is found that lower thermal resistance is consistent with more vibrational density of states overlaps at the interface. Our results are instructive for improving the interfacial thermal transport in graphene-based nanocomposites and nanofluids.