The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Snehasis Kundu - One of the best experts on this subject based on the ideXlab platform.
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modeling stratified Suspension Concentration distribution in turbulent flow using fractional advection diffusion equation
Environmental Fluid Mechanics, 2019Co-Authors: Snehasis KunduAbstract:The distribution of suspended sediment particles in a steady, uniform and stratified turbulent flow through open-channels is investigated in this study using fractional advection–diffusion equation (FADE). Unlike previous studies on FADE, the FADE is employed with the effects of stratification due to the presence of the sediment particles. Analogous to the approach of stratified flow, the effect of stratification is connected with the damping of the sediment diffusivity. A general model of sediment diffusion coefficient in stratified flow is proposed which changes along vertical direction as well as with the order of the fractional derivative. Finally the model of sediment distribution is derived incorporating the effects of non-local transport of particles, stratification, hindered settling velocity and damping of mixing length. The model is solved numerically using the fractional Adams–Bashforth–Moulton method and solutions are validated with the experimental data. The validation results are satisfactory. The variation of the depth average sediment diffusion coefficient and the proposed model of sediment diffusion coefficient with the fractional order $$\alpha$$ are investigated. The results show that with the decrease of fractional order $$\alpha$$, the value of depth average sediment diffusion coefficient increases and the depth variable sediment diffusion coefficient shows a overall increases throughout the flow depth. The rationality of the dependence of $$\alpha$$ on both types of sediment diffusion coefficients have been justified physically. It is also found that the effect of stratification results a decrease both for the Suspension distribution and the sediment diffusion coefficient which is consistent with the results using traditional ADE.
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Modeling stratified Suspension Concentration distribution in turbulent flow using fractional advection–diffusion equation
Environmental Fluid Mechanics, 2019Co-Authors: Snehasis KunduAbstract:The distribution of suspended sediment particles in a steady, uniform and stratified turbulent flow through open-channels is investigated in this study using fractional advection–diffusion equation (FADE). Unlike previous studies on FADE, the FADE is employed with the effects of stratification due to the presence of the sediment particles. Analogous to the approach of stratified flow, the effect of stratification is connected with the damping of the sediment diffusivity. A general model of sediment diffusion coefficient in stratified flow is proposed which changes along vertical direction as well as with the order of the fractional derivative. Finally the model of sediment distribution is derived incorporating the effects of non-local transport of particles, stratification, hindered settling velocity and damping of mixing length. The model is solved numerically using the fractional Adams–Bashforth–Moulton method and solutions are validated with the experimental data. The validation results are satisfactory. The variation of the depth average sediment diffusion coefficient and the proposed model of sediment diffusion coefficient with the fractional order $$\alpha$$ α are investigated. The results show that with the decrease of fractional order $$\alpha$$ α , the value of depth average sediment diffusion coefficient increases and the depth variable sediment diffusion coefficient shows a overall increases throughout the flow depth. The rationality of the dependence of $$\alpha$$ α on both types of sediment diffusion coefficients have been justified physically. It is also found that the effect of stratification results a decrease both for the Suspension distribution and the sediment diffusion coefficient which is consistent with the results using traditional ADE.
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Suspension Concentration distribution in turbulent flows an analytical study using fractional advection diffusion equation
Physica A-statistical Mechanics and Its Applications, 2018Co-Authors: Snehasis KunduAbstract:Abstract In this study vertical distribution of sediment particles in steady uniform turbulent open channel flow over erodible bed is investigated using fractional advection–diffusion equation (fADE). Unlike previous investigations on fADE to investigate the Suspension distribution, in this study the modified Atangana–Baleanu–Caputo fractional derivative with a non-singular and non-local kernel is employed. The proposed fADE is solved and an analytical model for finding vertical Suspension distribution is obtained. The model is validated against experimental as well as field measurements of Missouri River, Mississippi River and Rio Grande conveyance channel and is compared with the Rouse equation and other fractional model found in literature. A quantitative error analysis shows that the proposed model is able to predict the vertical distribution of particles more appropriately than previous models. The validation results shows that the fractional model can be equally applied to all size of particles with an appropriate choice of the order of the fractional derivative α . It is also found that besides particle diameter, parameter α depends on the mass density of particle and shear velocity of the flow. To predict this parameter, a multivariate regression is carried out and a relation is proposed for easy application of the model. From the results for sand and plastic particles, it is found that the parameter α is more sensitive to mass density than the particle diameter. The rationality of the dependence of α on particle and flow characteristics has been justified physically.
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derivation of hunt equation for Suspension distribution using shannon entropy theory
Physica A-statistical Mechanics and Its Applications, 2017Co-Authors: Snehasis KunduAbstract:In this study, the Hunt equation for computing Suspension Concentration in sediment-laden flows is derived using Shannon entropy theory. Considering the inverse of the void ratio as a random variable and using principle of maximum entropy, probability density function and cumulative distribution function of Suspension Concentration is derived. A new and more general cumulative distribution function for the flow domain is proposed which includes several specific other models of CDF reported in literature. This general form of cumulative distribution function also helps to derive the Rouse equation. The entropy based approach helps to estimate model parameters using Suspension data of sediment Concentration which shows the advantage of using entropy theory. Finally model parameters in the entropy based model are also expressed as functions of the Rouse number to establish a link between the parameters of the deterministic and probabilistic approaches.
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Effect of lateral bed roughness variation on particle Suspension in open channels
Environmental Earth Sciences, 2016Co-Authors: Snehasis KunduAbstract:In this paper the effect of variation of bed roughness along lateral direction on Suspension Concentration distribution in open channel turbulent flows was investigated. Starting from the mass and momentum conservation equations, this study demonstrates that both the Reynolds shear stress $$(-\overline{u'v'})$$ ( - u ′ v ′ ¯ ) and sediment diffusivity depends on bed roughness. From the theoretical analysis, it is found that both the Reynolds shear stress and the sediment diffusivity increase over smooth bed surfaces and decrease over rough bed surfaces. At the junction of smooth and rough bed surface, the effect of bed roughness on the Reynolds shear stress and sediment diffusion is almost negligible. Including this effect, Suspension Concentration distribution is also studied and from the Hunt’s diffusion equation, an analytical model for predicting Suspension Concentration is proposed. Apart from this effect, the effects of moveable bed roughness and stratification are also considered in the model. It is observed that the Rouse equation is obtained from the proposed model as a special case when the flow is considered as single phase and there is no effect of secondary current, stratification and bed roughness variation. On the basis of experimental data available in literature, the proposed model is validated and also compared with the Rouse equation. To get a quantitative idea about the goodness of fit, weighted relative error is calculated. The comparison results and calculated errors indicate that the present model is capable of describing the Suspension Concentration distribution more accurately than Rouse model throughout the flow depth in open channel flow.
Jaime C Grunlan - One of the best experts on this subject based on the ideXlab platform.
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influence of clay Concentration on the gas barrier of clay polymer nanobrick wall thin film assemblies
Langmuir, 2011Co-Authors: Morgan A. Priolo, Kevin M. Holder, Daniel Gamboa, Jaime C GrunlanAbstract:The influence of the clay deposition Suspension Concentration on gas barrier thin films of sodium montmorillonite (MMT) clay and branched polyethylenimine (PEI), created via layer-by-layer assembly, was investigated. Films grown with MMT Suspension Concentrations ranging from 0.05 to 2.0 wt % were analyzed for their growth as a function of deposited polymer–clay bilayers (BL) and their thickness, clay Concentration, transparency, nanostructure, and oxygen barrier as a function of the Suspension Concentration. The film thickness doubles and the visible light transmission decreases less than 5% as a function of MMT Concentration for 20-BL films. Atomic force and transmission electron microscope images reveal a highly aligned nanobrick wall structure, with quartz crystal microbalance measurements revealing a slight increase in the film clay Concentration as the MMT Suspension Concentration increases. The oxygen transmission rate (OTR) through these 20-BL composites, deposited on a 179 μm poly(ethylene tereph...
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Influence of clay Concentration on the gas barrier of clay-polymer nanobrick wall thin film assemblies.
Langmuir : the ACS journal of surfaces and colloids, 2011Co-Authors: Morgan A. Priolo, Kevin M. Holder, Daniel Gamboa, Jaime C GrunlanAbstract:The influence of the clay deposition Suspension Concentration on gas barrier thin films of sodium montmorillonite (MMT) clay and branched polyethylenimine (PEI), created via layer-by-layer assembly, was investigated. Films grown with MMT Suspension Concentrations ranging from 0.05 to 2.0 wt % were analyzed for their growth as a function of deposited polymer-clay bilayers (BL) and their thickness, clay Concentration, transparency, nanostructure, and oxygen barrier as a function of the Suspension Concentration. The film thickness doubles and the visible light transmission decreases less than 5% as a function of MMT Concentration for 20-BL films. Atomic force and transmission electron microscope images reveal a highly aligned nanobrick wall structure, with quartz crystal microbalance measurements revealing a slight increase in the film clay Concentration as the MMT Suspension Concentration increases. The oxygen transmission rate (OTR) through these 20-BL composites, deposited on a 179 μm poly(ethylene terephthalate) film, decreases exponentially as a function of the MMT clay Concentration. A 24-BL film created with 2.0 wt % MMT has an OTR below the detection limit of commercial instrumentation (
Weishen Yang - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and properties of A-type zeolite membranes by secondary growth method with vacuum seeding
Journal of Membrane Science, 2004Co-Authors: Aisheng Huang, Yuehe Lin, Weishen YangAbstract:A-type zeolite membranes were successfully synthesized on tubular -Al2O3 supports by secondary growth method with vacuum seeding. In the seeding process, a thin, uniform and continuous seeding layer was closely attached to the support surface by the pressure difference between the two sides of the support wall. The effects of seed particle size, Suspension Concentration, coating pressure difference and coating time on the membrane and its pervaporation properties were investigated. The as-synthesized membranes were characterized by XRD and SEM. The quality of the membranes was evaluated by the pervaporation dehydration of 95 wt.% isopropanol/water mixture at 343 K. High quality A-type zeolite membranes can be reproducibly prepared by the secondary growth method with vacuum seeding under the conditions: seed particle size of 500–1200 nm, Suspension Concentration of 4–8 g/l, coating pressure difference of 0.0100–0.0250 MPa and coating time of 45–180 s. © 2004 Elsevier B.V. All rights reserved.
Caroline S.b. Fitzpatrick - One of the best experts on this subject based on the ideXlab platform.
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Suspension Concentration profiles during rapid gravity filter backwashing
Chemical Engineering Journal, 2000Co-Authors: David J. Hall, Caroline S.b. FitzpatrickAbstract:Rapid gravity, granular media filters are widely used in the water and wastewater treatment industries. Regular backwashing to clean the filters is a vital part of their efficient operation. Experimental data on the development of Suspension Concentration profiles through laboratory scale filter beds during the backwash process were obtained. Previous attempts to obtain and record backwash profiles of this type have been unsuccessful due to the limited range of existing turbidimeters. The results have been used to validate a new model developed by the authors.
Yih-chi Tan - One of the best experts on this subject based on the ideXlab platform.
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Measurement of solid Suspension Concentration and flow velocity with temperature compensation using a portable ultrasonic device
Hydrological Sciences Journal, 2013Co-Authors: Y. J. Huang, C. C. Sung, Jihn-sung Lai, Fong-zuo Lee, G. W. Hwang, Yih-chi TanAbstract:Abstract Ultrasonic spectroscopy is highly suitable for real-time measurement, in particular for dense particle systems. In the present study, a novel measurement device, namely a portable ultrasonic device (PUD), is designed and manufactured for measuring solid Suspension Concentration and flow velocity simultaneously with respect to the propagation of ultrasound waves in a solid–liquid mixture at different temperatures. A series of experiments were conducted in the laboratory to obtain the ultrasonic attenuation of kaolin and reservoir sediment solutions within a wide range of Concentrations (1000–300 000 mg/L) at various temperatures (15–27°C). The resulting data were regressed to establish linear functions of attenuation and temperature for Concentration. The experimental data were compared with theoretical simulated results to show the effect of particle size distribution on Concentration measurement. The flow meter part of the PUD was verified by a standard-speed carriage in the towing tank. Accordi...
