The present paper is concerned with the steady thin film flow of the Sisko fluid on a horizontal moving plate, where the surface tension gradient is a driving mechanism. The analytic solution for the resulting nonline...The present paper is concerned with the steady thin film flow of the Sisko fluid on a horizontal moving plate, where the surface tension gradient is a driving mechanism. The analytic solution for the resulting nonlinear ordinary differential equation is obtained by the Adomian decomposition method (ADM). The physical quantities are derived including the pressure profile, the velocity profile, the maximum residue time, the stationary points, the volume flow rate, the average film velocity, the uniform film thickness, the shear stress, the surface tension profile~ and the vorticity vector. It is found that the velocity of the Sisko fluid film decreases when the fluid behavior index and the Sisko fluid parameter increase, whereas it increases with an increase in the inverse capillary number. An increase in the inverse capillary number results in an increase in the surface tension which in turn results in an increase in the surface tension gradient on the Sisko fluid film. The locations of the stationary points are shifted towards the moving plate with the increase in the inverse capillary number, and vice versa locations for the stationary points are found with the increasing Sisko fluid parameter. Furthermore, shear thinning and shear thickening characteristics of the Sisko fluid are discussed. A comparison is made between the Sisko fluid film and the Newtonian fluid film.展开更多
In this paper, He’s variational iteration method is successfully employed to solve a nonlinear boundary value problem arising in the study of thin film flow of a third grade fluid down an inclined plane. For comparis...In this paper, He’s variational iteration method is successfully employed to solve a nonlinear boundary value problem arising in the study of thin film flow of a third grade fluid down an inclined plane. For comparison, the same problem is solved by the Adomian decomposition method. The results show that the difference between the two solutions is negligible. The conclusion is that this technique may be considered an alternative and efficient method for finding approximate solutions of both linear and nonlinear boundary value problems. Furthermore, the variational iteration method has an advantage over the decomposition method in that it solves the nonlinear problems without using the Adomian polynomials.展开更多
The physical problem of the thin film flow of a micropolar fluid over a dynamic and inclined substrate under the influence of gravitational and thermal forces in the presence of nanoparticles is formulated.Five differ...The physical problem of the thin film flow of a micropolar fluid over a dynamic and inclined substrate under the influence of gravitational and thermal forces in the presence of nanoparticles is formulated.Five different types of nanoparticle samples are accounted for in this current study,namely gold Au,silver Ag,molybdenum disulfide MoS2,aluminum oxide Al2O3,and silicon dioxide SiO2.Blood,a micropolar fluid,serves as the common base fluid.An exact closed-form solution for this problem is derived for the first time in the literature.The results are particularly validated against those for the Newtonian fluid and show excellent agreement.It was found that increasing values of the spin boundary condition and micropolarity lead to a reduction in both the thermal and momentum boundary layers.A quantitative decay in the Nusselt number for a micropolar fluid,as compared to a Newtonian one for all the tested nanoparticles,is anticipated.Gold and silver nanoparticles(i)intensify in the flow parameter as the concentration of nanoparticles increases(ii)yield a higher thermal transfer rate,whereas molybdenum disulfide,aluminum oxide,and silicon dioxide exhibit a converse attitude for both Newtonian and micropolar fluids.The reduction in film thickness for fluid comprising gold particles,as compared to the rest of the nanoparticles,is remarkable.展开更多
We investigate, in this paper, the effects of thermo-physical properties on the flow and heat transfer in a thin film of a power-law liquid over a horizontal stretching surface in the presence of a viscous dissipation...We investigate, in this paper, the effects of thermo-physical properties on the flow and heat transfer in a thin film of a power-law liquid over a horizontal stretching surface in the presence of a viscous dissipation. The fluid properties, namely the fluid viscosity and the fluid thermal conductivity, are assumed to vary with temperature. Using a similarity transformation, the governing partial differential equations with a time dependent boundary are converted into coupled non-linear Ordinary Differential Equations (ODEs) with variable coefficients. Numerical solutions of the coupled ODEs are obtained by a finite difference scheme known as the Keller-box method. Results for the velocity and temperature distributions are presented graphically for different values of the pertinent parameters. The effects of unsteady parameter on the skin friction, the wall temperature gradient and the film thickness are presented and analyzed for zero and non-zero values of the temperature-dependent thermo-physical properties. The results obtained reveal many interesting features that warrant further study on the non-Newtonian thin film fluid flow phenomena, especially the shear-thinning phenomena.展开更多
Centrifugal and shear forces are produced when solids or liquids rotate.Rotary systems and devices that use these forces,such as dynamic thin-film flow technology,are evolving continuously,improve material structure-p...Centrifugal and shear forces are produced when solids or liquids rotate.Rotary systems and devices that use these forces,such as dynamic thin-film flow technology,are evolving continuously,improve material structure-property relationships at the nanoscale,representing a rapidly thriving and expanding field of research high with green chemistry metrics,consolidated at the inception of science.The vortex fluidic device(VFD)provides many advantages over conventional batch processing,with fluidic waves causing high shear and producing large surface areas for micro-mixing as well as rapid mass and heat transfer,enabling reactions beyond diffusion control.Combining these abilities allows for a green and innovative approach to altering materials for various research and industry applications by controlling small-scale flows and regulating molecular and macromolecular chemical reactivity,self-organization phenomena,and the synthesis of novel materials.This review highlights the aptitude of the VFD as clean technology,with an increase in efficiency for a diversity of top-down,bottom-up,and novel material transformations which benefit from effective vortex-based processing to control material structure-property relationships.展开更多
Zinc oxide(ZnO) thin films were deposited onto different substrates — tin-doped indium oxide(ITO)/glass, ITO/polyethylene naphthalate(PEN), ITO/polyethylene terephthalate(PET) — by the radio-frequency(RF) magnetron ...Zinc oxide(ZnO) thin films were deposited onto different substrates — tin-doped indium oxide(ITO)/glass, ITO/polyethylene naphthalate(PEN), ITO/polyethylene terephthalate(PET) — by the radio-frequency(RF) magnetron sputtering method. The effect of various O2/(Ar+O2) gas flow ratios(0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6) was studied in detail. ZnO layers deposited onto ITO/PEN and ITO/PET substrates exhibited a stronger c-axis preferred orientation along the(0002) direction compared to ZnO deposited onto ITO/glass. The transmittance spectra of ZnO films showed that the maximum transmittances of ZnO films deposited onto ITO/glass, ITO/PEN, and ITO/PET substrates were 89.2%, 65.0%, and 77.8%, respectively. Scanning electron microscopy(SEM) images of the film surfaces indicated that the grain was uniform. The cross-sectional SEM images showed that the ZnO films were columnar structures whose c-axis was perpendicular to the film surface. The test results for a fabricated ZnO thin film based energy harvester showed that its output voltage increased with increasing acceleration of external vibration.展开更多
A new variational method is proposed to investigate the dynamics of the thin film in a coating flow where a liquid is delivered through a fixed slot gap onto a moving substrate. A simplified ODE system has also been d...A new variational method is proposed to investigate the dynamics of the thin film in a coating flow where a liquid is delivered through a fixed slot gap onto a moving substrate. A simplified ODE system has also been derived for the evolution of the thin film whose thickness hf is asymptotically constant behind the coating front. We calculate the phase diagram as well as the film profiles and approximate the film thickness theoretically, and agreement with the well-known scaling law as Ca2/3 is found.展开更多
In This paper, we deal with the study of the effect of magnetohydrodynamic on thin films of unsteady micropolar fluid through a porous medium. These Thin films are considered for three different geometries. The govern...In This paper, we deal with the study of the effect of magnetohydrodynamic on thin films of unsteady micropolar fluid through a porous medium. These Thin films are considered for three different geometries. The governing continuity, momentum and angular momentum equations are converted into a system of non-linear ordinary differential equations by means of similarity transformation. The resulting system of coupled non-linear ordinary differential equations is solved numerically by using shooting method. A representative set of numerical results in the three thin film flow problems for velocity and micro-rotation profiles are discussed and presented graphically. A comprehensive parametric study is carried out to show the effects of the micropolar fluid parameters, magnetic field parameter, permeability parameter and etc. on the obtained solutions.展开更多
Waves of finite amplitude on a thin layer of non-Newtonian fluid modelled as a power-law fluid are considered. In the long wave approximation, the system of equations taking into account the viscous and nonlinear effe...Waves of finite amplitude on a thin layer of non-Newtonian fluid modelled as a power-law fluid are considered. In the long wave approximation, the system of equations taking into account the viscous and nonlinear effects has the hyper- bolic type. For the two-parameter family of periodic waves in the film flow on a vertical wall the modulation equations for nonlinear wave trains are derived and investigated. The stability criterium for roll waves based on the hyperbolicity of the modulation equations is suggested. It is shown that the evolution of stable roll waves can be described by self-similar solutions of the modulation equations.展开更多
The impact of the Marangoni convection over the thin film flow on an expanding cylinder has been examined in this study. The diverse effect of the embedded constraints has been detected during the liquid film flow. It...The impact of the Marangoni convection over the thin film flow on an expanding cylinder has been examined in this study. The diverse effect of the embedded constraints has been detected during the liquid film flow. It has been examined that the behavior of the physical parameters altered after the small intervals and diverse from the traditional approach. The similarity variables have been utilized to alter the basic flow equations into the nonlinear ordinary differential equations. The result of the transformed equations is computed by BVPh 2.0 package. The performance of different constraints, for flow motion and temperature distributions are plotted and conferred. It has been observed that under the Marangoni convection the impact of the physical parameters varies after the point of inflection and the diverse impact of the embedding constraints provide space for the variation of the point of inflection for the desired spray analysis.展开更多
In this paper, polycrystalline silicon films were deposited by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR-PECVD) using SiH4/Ar and SiH4/H2 gaseous mixture. Effects of argon flow rate...In this paper, polycrystalline silicon films were deposited by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR-PECVD) using SiH4/Ar and SiH4/H2 gaseous mixture. Effects of argon flow rate on the deposition efficiency and the film property were investigated by comparing with H2. The results indicated that the deposition rate of using Ar as discharge gas was 1.5-2 times higher than that of using H2, while the preferred orientations and the grain sizes of the films were analogous. Film crystallinity increased with the increase of Ar flow rate. Optimized flow ratio of SiH4 to Ar was obtained as F(SiH4): F(Ar)=10:70 for the highest deposition rate.展开更多
文摘The present paper is concerned with the steady thin film flow of the Sisko fluid on a horizontal moving plate, where the surface tension gradient is a driving mechanism. The analytic solution for the resulting nonlinear ordinary differential equation is obtained by the Adomian decomposition method (ADM). The physical quantities are derived including the pressure profile, the velocity profile, the maximum residue time, the stationary points, the volume flow rate, the average film velocity, the uniform film thickness, the shear stress, the surface tension profile~ and the vorticity vector. It is found that the velocity of the Sisko fluid film decreases when the fluid behavior index and the Sisko fluid parameter increase, whereas it increases with an increase in the inverse capillary number. An increase in the inverse capillary number results in an increase in the surface tension which in turn results in an increase in the surface tension gradient on the Sisko fluid film. The locations of the stationary points are shifted towards the moving plate with the increase in the inverse capillary number, and vice versa locations for the stationary points are found with the increasing Sisko fluid parameter. Furthermore, shear thinning and shear thickening characteristics of the Sisko fluid are discussed. A comparison is made between the Sisko fluid film and the Newtonian fluid film.
文摘In this paper, He’s variational iteration method is successfully employed to solve a nonlinear boundary value problem arising in the study of thin film flow of a third grade fluid down an inclined plane. For comparison, the same problem is solved by the Adomian decomposition method. The results show that the difference between the two solutions is negligible. The conclusion is that this technique may be considered an alternative and efficient method for finding approximate solutions of both linear and nonlinear boundary value problems. Furthermore, the variational iteration method has an advantage over the decomposition method in that it solves the nonlinear problems without using the Adomian polynomials.
基金The authors did not receive any funding support from any source.It is self-financed solely.
文摘The physical problem of the thin film flow of a micropolar fluid over a dynamic and inclined substrate under the influence of gravitational and thermal forces in the presence of nanoparticles is formulated.Five different types of nanoparticle samples are accounted for in this current study,namely gold Au,silver Ag,molybdenum disulfide MoS2,aluminum oxide Al2O3,and silicon dioxide SiO2.Blood,a micropolar fluid,serves as the common base fluid.An exact closed-form solution for this problem is derived for the first time in the literature.The results are particularly validated against those for the Newtonian fluid and show excellent agreement.It was found that increasing values of the spin boundary condition and micropolarity lead to a reduction in both the thermal and momentum boundary layers.A quantitative decay in the Nusselt number for a micropolar fluid,as compared to a Newtonian one for all the tested nanoparticles,is anticipated.Gold and silver nanoparticles(i)intensify in the flow parameter as the concentration of nanoparticles increases(ii)yield a higher thermal transfer rate,whereas molybdenum disulfide,aluminum oxide,and silicon dioxide exhibit a converse attitude for both Newtonian and micropolar fluids.The reduction in film thickness for fluid comprising gold particles,as compared to the rest of the nanoparticles,is remarkable.
基金the University Grants Commission,New Delhi for supporting financially under Major Research Project(Grant No. 41-790/2012(SR))
文摘We investigate, in this paper, the effects of thermo-physical properties on the flow and heat transfer in a thin film of a power-law liquid over a horizontal stretching surface in the presence of a viscous dissipation. The fluid properties, namely the fluid viscosity and the fluid thermal conductivity, are assumed to vary with temperature. Using a similarity transformation, the governing partial differential equations with a time dependent boundary are converted into coupled non-linear Ordinary Differential Equations (ODEs) with variable coefficients. Numerical solutions of the coupled ODEs are obtained by a finite difference scheme known as the Keller-box method. Results for the velocity and temperature distributions are presented graphically for different values of the pertinent parameters. The effects of unsteady parameter on the skin friction, the wall temperature gradient and the film thickness are presented and analyzed for zero and non-zero values of the temperature-dependent thermo-physical properties. The results obtained reveal many interesting features that warrant further study on the non-Newtonian thin film fluid flow phenomena, especially the shear-thinning phenomena.
基金Postgraduate Research Scholarship and Flinders University Research Investment Fund 2022,and the Australian Research Council,Grant/Award Numbers:DP200101105,DP200101106。
文摘Centrifugal and shear forces are produced when solids or liquids rotate.Rotary systems and devices that use these forces,such as dynamic thin-film flow technology,are evolving continuously,improve material structure-property relationships at the nanoscale,representing a rapidly thriving and expanding field of research high with green chemistry metrics,consolidated at the inception of science.The vortex fluidic device(VFD)provides many advantages over conventional batch processing,with fluidic waves causing high shear and producing large surface areas for micro-mixing as well as rapid mass and heat transfer,enabling reactions beyond diffusion control.Combining these abilities allows for a green and innovative approach to altering materials for various research and industry applications by controlling small-scale flows and regulating molecular and macromolecular chemical reactivity,self-organization phenomena,and the synthesis of novel materials.This review highlights the aptitude of the VFD as clean technology,with an increase in efficiency for a diversity of top-down,bottom-up,and novel material transformations which benefit from effective vortex-based processing to control material structure-property relationships.
基金supported by the National Natural Science Foundation of China (61671017)Anhui Provincial Natural Science Foundation (1508085ME72)the Provincial Natural Science Foundation of Anhui Higher Education Institution (KJ2016A787)
文摘Zinc oxide(ZnO) thin films were deposited onto different substrates — tin-doped indium oxide(ITO)/glass, ITO/polyethylene naphthalate(PEN), ITO/polyethylene terephthalate(PET) — by the radio-frequency(RF) magnetron sputtering method. The effect of various O2/(Ar+O2) gas flow ratios(0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6) was studied in detail. ZnO layers deposited onto ITO/PEN and ITO/PET substrates exhibited a stronger c-axis preferred orientation along the(0002) direction compared to ZnO deposited onto ITO/glass. The transmittance spectra of ZnO films showed that the maximum transmittances of ZnO films deposited onto ITO/glass, ITO/PEN, and ITO/PET substrates were 89.2%, 65.0%, and 77.8%, respectively. Scanning electron microscopy(SEM) images of the film surfaces indicated that the grain was uniform. The cross-sectional SEM images showed that the ZnO films were columnar structures whose c-axis was perpendicular to the film surface. The test results for a fabricated ZnO thin film based energy harvester showed that its output voltage increased with increasing acceleration of external vibration.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.91630208,91641107,and 11771437)
文摘A new variational method is proposed to investigate the dynamics of the thin film in a coating flow where a liquid is delivered through a fixed slot gap onto a moving substrate. A simplified ODE system has also been derived for the evolution of the thin film whose thickness hf is asymptotically constant behind the coating front. We calculate the phase diagram as well as the film profiles and approximate the film thickness theoretically, and agreement with the well-known scaling law as Ca2/3 is found.
文摘In This paper, we deal with the study of the effect of magnetohydrodynamic on thin films of unsteady micropolar fluid through a porous medium. These Thin films are considered for three different geometries. The governing continuity, momentum and angular momentum equations are converted into a system of non-linear ordinary differential equations by means of similarity transformation. The resulting system of coupled non-linear ordinary differential equations is solved numerically by using shooting method. A representative set of numerical results in the three thin film flow problems for velocity and micro-rotation profiles are discussed and presented graphically. A comprehensive parametric study is carried out to show the effects of the micropolar fluid parameters, magnetic field parameter, permeability parameter and etc. on the obtained solutions.
文摘Waves of finite amplitude on a thin layer of non-Newtonian fluid modelled as a power-law fluid are considered. In the long wave approximation, the system of equations taking into account the viscous and nonlinear effects has the hyper- bolic type. For the two-parameter family of periodic waves in the film flow on a vertical wall the modulation equations for nonlinear wave trains are derived and investigated. The stability criterium for roll waves based on the hyperbolicity of the modulation equations is suggested. It is shown that the evolution of stable roll waves can be described by self-similar solutions of the modulation equations.
文摘The impact of the Marangoni convection over the thin film flow on an expanding cylinder has been examined in this study. The diverse effect of the embedded constraints has been detected during the liquid film flow. It has been examined that the behavior of the physical parameters altered after the small intervals and diverse from the traditional approach. The similarity variables have been utilized to alter the basic flow equations into the nonlinear ordinary differential equations. The result of the transformed equations is computed by BVPh 2.0 package. The performance of different constraints, for flow motion and temperature distributions are plotted and conferred. It has been observed that under the Marangoni convection the impact of the physical parameters varies after the point of inflection and the diverse impact of the embedding constraints provide space for the variation of the point of inflection for the desired spray analysis.
文摘In this paper, polycrystalline silicon films were deposited by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR-PECVD) using SiH4/Ar and SiH4/H2 gaseous mixture. Effects of argon flow rate on the deposition efficiency and the film property were investigated by comparing with H2. The results indicated that the deposition rate of using Ar as discharge gas was 1.5-2 times higher than that of using H2, while the preferred orientations and the grain sizes of the films were analogous. Film crystallinity increased with the increase of Ar flow rate. Optimized flow ratio of SiH4 to Ar was obtained as F(SiH4): F(Ar)=10:70 for the highest deposition rate.