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Tasawar Hayat - One of the best experts on this subject based on the ideXlab platform.
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darcy forchheimer characteristics of viscoelastic stratified nanoliquid by convectively heated permeable surface
Thermal Science, 2019Co-Authors: Sadiq Adil Muhammad, M Waqas, Tasawar HayatAbstract:A nonlinear mathematical analysis for non-Darcian magneto-viscoelastic nanoliquid is elaborated in this research. Flow is caused by stratified surface having permeable nature. The Robin's type boundary conditions are imposed at moving surface. Brownian Diffusion, heat source and thermophoretic aspects are accounted. Complex systems are simplified through the well-known boundary-layer concept which is subsequently transfigured to ordinary ones via transformation technique. Furthermore the meaningful physical variables arising in non-dimensional problems are elucidated via graphs.
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an optimal analysis for darcy forchheimer 3d flow of nanofluid with convective condition and homogeneous heterogeneous reactions
Physics Letters A, 2018Co-Authors: Tasawar Hayat, Arsalan Aziz, Taseer Muhammad, Ahmed AlsaediAbstract:Abstract Here Darcy–Forchheimer 3D stretching flow of nanoliquid in the presence of convective condition and homogeneous–heterogeneous reactions is analyzed. Impacts of thermophoresis, Brownian Diffusion and zero nanoparticles mass flux condition are considered. Adequate transformation procedure give rise to system in terms of ordinary differential equations. The governing mathematical system has been tackled by optimal homotopic technique. Graphical results have been presented for temperature and concentration dsitributions. Numerical benchmark is provided to study the values of skin friction coefficients and local Nusselt number. Skin friction coefficients are declared increasing functions of porosity and Forchheimer parameters. Furthermore the local Nusselt number is reduced for larger values of porosity and Forchheimer parameters.
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an optimal analysis for darcy forchheimer 3d flow of carreau nanofluid with convectively heated surface
Results in physics, 2018Co-Authors: Tasawar Hayat, Arsalan Aziz, Taseer Muhammad, Ahmed AlsaediAbstract:Abstract Darcy-Forchheimer three dimensional flow of Carreau nanoliquid induced by a linearly stretchable surface with convective boundary condition has been analyzed. Buongiorno model has been employed to elaborate thermophoresis and Brownian Diffusion effects. Zero nanoparticles mass flux and convective surface conditions are implemented at the boundary. The governing problems are nonlinear. Optimal homotopic procedure has been used to tackle the governing mathematical system. Graphical results clearly depict the outcome of temperature and concentration fields. Surface drag coefficients and local Nusselt number are also plotted and discussed.
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nonlinear thermal radiation in flow induced by a slendering surface accounting thermophoresis and Brownian Diffusion
European Physical Journal Plus, 2017Co-Authors: Muhammad Waqas, Tasawar Hayat, Ijaz M Khan, A Alsaedi, Imran M KhanAbstract:Our attention here in this research is on scrutinizing the nonlinear convection characteristics in a flow induced by a slendering surface. Flow expression is developed through electrically conducting Williamson nanomaterial. Nonlinear forms of stretching and free stream velocities are imposed. Consideration of nonlinear thermal radiation, non-uniform heat generation/absorption, Joule and convective heating aspects describe the phenomenon of heat transfer. The zero-mass condition for concentration is also considered. The compatible transformations produce strong nonlinear differential systems. The problems are computed analytically utilizing the bvp4c procedure. Heat transfer rate and drag force are also explained for various physical variables. Our analysis reveals that the heat transfer rate augments via larger radiation parameter and Biot number. Moreover, larger Brownian motion and thermophoresis parameters have opposite characteristics on concentration field. For the verification of the present findings, the results of the presented analysis have been compared with the available works in particular situations and reasonable agreement is noted.
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an optimal study for three dimensional flow of maxwell nanofluid subject to rotating frame
Journal of Molecular Liquids, 2017Co-Authors: Tasawar Hayat, Taseer Muhammad, M Mustafa, A AlsaediAbstract:Abstract Here we are concerned with optimal homotopy solutions for three-dimensional flow of Maxwell nanofluid in rotating frame. Flow is induced by uniform stretching of the boundary surface in one direction. Buongiorno model is adopted which features the novel aspects of Brownian Diffusion and thermophoresis. Boundary layer approximations are invoked to simplify the governing system of partial differential equations. Appropriate relations are introduced to nondimensionalize the relevant boundary layer expressions. Newly suggested condition associated with zero nanoparticles mass flux at the boundary is imposed. Uniformly valid convergent solution expressions are developed by means of optimal homotopy analysis method (OHAM). Plots have been portrayed in order to explain the role of embedded flow parameters on the solutions. Heat transfer rate at the surface has been computed and analyzed. Our findings show that the temperature and concentration fields are smaller for Newtonian fluid when compared with the upper-convected Maxwell (UCM). Moreover Brownian Diffusion has mild influence of heat flux at the boundary. Viscoelastic effect has tendency to reduce heat transfer rate from the stretching boundary.
Ioan Pop - One of the best experts on this subject based on the ideXlab platform.
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effect of local heater size and position on natural convection in a tilted nanofluid porous cavity using ltne and buongiorno s models
Journal of Molecular Liquids, 2018Co-Authors: Mikhail A Sheremet, Ioan PopAbstract:Abstract Natural convection heat transfer within nanofluid porous cavities with local heaters occurs in different engineering applications. Therefore, analysis of nanofluid flow and heat transfer patterns in such systems has a significant value for development of industry. In the present study, free convection of nanofluid in a tilted porous cavity with a local isothermal heater has been investigated numerically. Governing equations with corresponding initial and boundary conditions formulated using the Darcy–Boussinesq model and local thermal non-equilibrium approach have been solved by the finite difference method under the effects of Brownian Diffusion and thermophoresis. Effects of heater location (δ = 0.1–0.3) and dimensionless length (D = 0.2–0.8) as well as cavity inclination angle (γ = 0–π/2) and interphase heat transfer coefficient (H = 10–1000) on nanofluid flow and heat transfer have been studied for the following values of other governing parameters: Rayleigh number (Ra = 105), Prandtl number (Pr = 6.82), Darcy number (Da = 10−3), porosity of porous medium (e = 0.5), buoyancy ratio parameter (Nr = 1), Brownian Diffusion parameter (Nb = 10−6), thermophoresis parameter (Nt = 10−6), Lewis number (Le = 1000), thermal diffusivity ratio (Γ = 649.7) and heat capacitance ratio (ξ = 3.4). It has been found the heat transfer enhancement and convective flow attenuation when the distance between the heater and the cold vertical wall reduces.
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free convection in a partially heated wavy porous cavity filled with a nanofluid under the effects of Brownian Diffusion and thermophoresis
Applied Thermal Engineering, 2017Co-Authors: Mikhail A Sheremet, Dalia Sabina Cimpean, Ioan PopAbstract:Abstract Numerical analysis of natural convective heat transfer and fluid flow inside a porous wavy cavity filled with a nanofluid has been carried out. The domain of interest is a square cavity with a left isothermal wavy wall, while other walls are flat. A heat source of constant temperature is located on the right vertical wall. Governing equations formulated in terms of the dimensionless variables using the Darcy–Boussinesq approximation have been solved on the basis of finite difference method of the second order accuracy. The two-phase nanofluid model including the Brownian Diffusion and thermophoresis effects has been used for simulation of nanofluid transport inside the cavity. Analysis has been conducted in a wide range of the Rayleigh number, undulation number and heat source size. It has been found that the local heat source has an efficient influence of the nanofluid flow and heat transfer rate.
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Free Convection in Shallow and Slender Porous Cavities Filled by a Nanofluid Using Buongiorno's Model
Journal of Heat Transfer, 2014Co-Authors: Mikhail A Sheremet, Teodor Grosan, Ioan PopAbstract:A numerical study of the steady free convection flow in shallow and slender porous cavities filled by a nanofluid is presented. The nanofluid model takes into account the Brownian Diffusion and the thermophoresis effects. The governing dimensional partial differential equations are transformed into a dimensionless form before being solved numerically using a finite difference method. Effort has been focused on the effects of four types of influential factors such as the aspect ratio, the Rayleigh and Lewis numbers, and the buoyancy-ratio parameter on the fluid flow and heat transfer characteristics.
Mikhail A Sheremet - One of the best experts on this subject based on the ideXlab platform.
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effect of local heater size and position on natural convection in a tilted nanofluid porous cavity using ltne and buongiorno s models
Journal of Molecular Liquids, 2018Co-Authors: Mikhail A Sheremet, Ioan PopAbstract:Abstract Natural convection heat transfer within nanofluid porous cavities with local heaters occurs in different engineering applications. Therefore, analysis of nanofluid flow and heat transfer patterns in such systems has a significant value for development of industry. In the present study, free convection of nanofluid in a tilted porous cavity with a local isothermal heater has been investigated numerically. Governing equations with corresponding initial and boundary conditions formulated using the Darcy–Boussinesq model and local thermal non-equilibrium approach have been solved by the finite difference method under the effects of Brownian Diffusion and thermophoresis. Effects of heater location (δ = 0.1–0.3) and dimensionless length (D = 0.2–0.8) as well as cavity inclination angle (γ = 0–π/2) and interphase heat transfer coefficient (H = 10–1000) on nanofluid flow and heat transfer have been studied for the following values of other governing parameters: Rayleigh number (Ra = 105), Prandtl number (Pr = 6.82), Darcy number (Da = 10−3), porosity of porous medium (e = 0.5), buoyancy ratio parameter (Nr = 1), Brownian Diffusion parameter (Nb = 10−6), thermophoresis parameter (Nt = 10−6), Lewis number (Le = 1000), thermal diffusivity ratio (Γ = 649.7) and heat capacitance ratio (ξ = 3.4). It has been found the heat transfer enhancement and convective flow attenuation when the distance between the heater and the cold vertical wall reduces.
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transient natural convection in a partially open trapezoidal cavity filled with a water based nanofluid under the effects of Brownian Diffusion and thermophoresis
International Journal of Numerical Methods for Heat & Fluid Flow, 2018Co-Authors: Nadezhda S Bondareva, Hakan F Oztop, Mikhail A Sheremet, Nidal AbuhamdehAbstract:Purpose The purpose of this paper is to study about the natural convection of water-based nanofluid in a partially open trapezoidal cavity under the influence of Brownian Diffusion and thermophoresis. Design/methodology/approach Governing equations formulated in dimensionless stream function – vorticity variables – have been solved by finite difference method with a homemade code C++. Effects of Rayleigh number (Ra = 50-1,000), Lewis number (Le = 10-1,000), buoyancy-ratio parameter (Nr = 0.1-5.0), Brownian motion parameter (Nb = 0.1, 1.0) and thermophoresis parameter (Nt = 0.1, 1.0) on nanofluid flow and heat transfer have been studied. Findings It is found that high values of Rayleigh and Lewis numbers lead to the homogenization of nanoparticles distributions. For high values of Nt and Nb, heating is more essential and the cavity average temperature rises. Originality/value The originality of this work is to analyze natural convection in an open-sided trapezoidal cavity with Brownian Diffusion and thermophoresis.
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free convection in a partially heated wavy porous cavity filled with a nanofluid under the effects of Brownian Diffusion and thermophoresis
Applied Thermal Engineering, 2017Co-Authors: Mikhail A Sheremet, Dalia Sabina Cimpean, Ioan PopAbstract:Abstract Numerical analysis of natural convective heat transfer and fluid flow inside a porous wavy cavity filled with a nanofluid has been carried out. The domain of interest is a square cavity with a left isothermal wavy wall, while other walls are flat. A heat source of constant temperature is located on the right vertical wall. Governing equations formulated in terms of the dimensionless variables using the Darcy–Boussinesq approximation have been solved on the basis of finite difference method of the second order accuracy. The two-phase nanofluid model including the Brownian Diffusion and thermophoresis effects has been used for simulation of nanofluid transport inside the cavity. Analysis has been conducted in a wide range of the Rayleigh number, undulation number and heat source size. It has been found that the local heat source has an efficient influence of the nanofluid flow and heat transfer rate.
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Free Convection in Shallow and Slender Porous Cavities Filled by a Nanofluid Using Buongiorno's Model
Journal of Heat Transfer, 2014Co-Authors: Mikhail A Sheremet, Teodor Grosan, Ioan PopAbstract:A numerical study of the steady free convection flow in shallow and slender porous cavities filled by a nanofluid is presented. The nanofluid model takes into account the Brownian Diffusion and the thermophoresis effects. The governing dimensional partial differential equations are transformed into a dimensionless form before being solved numerically using a finite difference method. Effort has been focused on the effects of four types of influential factors such as the aspect ratio, the Rayleigh and Lewis numbers, and the buoyancy-ratio parameter on the fluid flow and heat transfer characteristics.
Taseer Muhammad - One of the best experts on this subject based on the ideXlab platform.
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effects of binary chemical reaction and arrhenius activation energy in darcy forchheimer three dimensional flow of nanofluid subject to rotating frame
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Arsalan Aziz, Taseer MuhammadAbstract:Darcy–Forchheimer three-dimensional rotating flow of nanoliquid in the presence of activation energy and heat generation/absorption is examined. Heat and mass transport via convective process is considered. Buongiorno model has been employed to illustrate thermophoresis and Brownian Diffusion effects. Adequate transformation procedure gives rise to system in terms of nonlinear ODE’s. An efficient numerical technique namely NDsolve is used to tackle the governing nonlinear system. The graphical illustrations examine the outcomes of various sundry variables. Heat and mass transfer rates are also computed and examined. Our results indicate that the temperature and concentration distributions are enhanced for larger values of porosity parameter and Forchheimer number.
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an optimal analysis for darcy forchheimer 3d flow of nanofluid with convective condition and homogeneous heterogeneous reactions
Physics Letters A, 2018Co-Authors: Tasawar Hayat, Arsalan Aziz, Taseer Muhammad, Ahmed AlsaediAbstract:Abstract Here Darcy–Forchheimer 3D stretching flow of nanoliquid in the presence of convective condition and homogeneous–heterogeneous reactions is analyzed. Impacts of thermophoresis, Brownian Diffusion and zero nanoparticles mass flux condition are considered. Adequate transformation procedure give rise to system in terms of ordinary differential equations. The governing mathematical system has been tackled by optimal homotopic technique. Graphical results have been presented for temperature and concentration dsitributions. Numerical benchmark is provided to study the values of skin friction coefficients and local Nusselt number. Skin friction coefficients are declared increasing functions of porosity and Forchheimer parameters. Furthermore the local Nusselt number is reduced for larger values of porosity and Forchheimer parameters.
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an optimal analysis for darcy forchheimer 3d flow of carreau nanofluid with convectively heated surface
Results in physics, 2018Co-Authors: Tasawar Hayat, Arsalan Aziz, Taseer Muhammad, Ahmed AlsaediAbstract:Abstract Darcy-Forchheimer three dimensional flow of Carreau nanoliquid induced by a linearly stretchable surface with convective boundary condition has been analyzed. Buongiorno model has been employed to elaborate thermophoresis and Brownian Diffusion effects. Zero nanoparticles mass flux and convective surface conditions are implemented at the boundary. The governing problems are nonlinear. Optimal homotopic procedure has been used to tackle the governing mathematical system. Graphical results clearly depict the outcome of temperature and concentration fields. Surface drag coefficients and local Nusselt number are also plotted and discussed.
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an optimal study for three dimensional flow of maxwell nanofluid subject to rotating frame
Journal of Molecular Liquids, 2017Co-Authors: Tasawar Hayat, Taseer Muhammad, M Mustafa, A AlsaediAbstract:Abstract Here we are concerned with optimal homotopy solutions for three-dimensional flow of Maxwell nanofluid in rotating frame. Flow is induced by uniform stretching of the boundary surface in one direction. Buongiorno model is adopted which features the novel aspects of Brownian Diffusion and thermophoresis. Boundary layer approximations are invoked to simplify the governing system of partial differential equations. Appropriate relations are introduced to nondimensionalize the relevant boundary layer expressions. Newly suggested condition associated with zero nanoparticles mass flux at the boundary is imposed. Uniformly valid convergent solution expressions are developed by means of optimal homotopy analysis method (OHAM). Plots have been portrayed in order to explain the role of embedded flow parameters on the solutions. Heat transfer rate at the surface has been computed and analyzed. Our findings show that the temperature and concentration fields are smaller for Newtonian fluid when compared with the upper-convected Maxwell (UCM). Moreover Brownian Diffusion has mild influence of heat flux at the boundary. Viscoelastic effect has tendency to reduce heat transfer rate from the stretching boundary.
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a revised model for stretched flow of third grade fluid subject to magneto nanoparticles and convective condition
Journal of Molecular Liquids, 2017Co-Authors: Tasawar Hayat, Taseer Muhammad, Ikram Ullah, Ahmed AlsaediAbstract:Abstract Magnetohydrodynamic (MHD) stretched flow of third-grade nanofluid with convective surface condition is examined. Third-grade fluid is electrically conducting subject to uniform magnetic field. Aspects of Brownian Diffusion and thermophoresis have been accounted. Newly suggested condition for zero nanoparticles mass flux is employed. Proper transformations are utilized to convert the partial differential system (PDE) into the non-linear ordinary differential system (ODE). The resulting nonlinear system is solved for the series solutions of velocity, temperature and concentration distributions. Convergence of the developed solutions is verified explicitly through tables and plots. Consequences of various influential variables on the non-dimensional temperature and concentration distributions are interpreted graphically. Skin friction coefficient and local Nusselt number are analyzed through plots and numerical data.
Alexander Wittemann - One of the best experts on this subject based on the ideXlab platform.
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3d Brownian Diffusion of submicron sized particle clusters
arXiv: Soft Condensed Matter, 2009Co-Authors: Martin Hoffmann, Claudia Simone Wagner, Ludger Harnau, Alexander WittemannAbstract:We report on the translation and rotation of particle clusters made through the combination of spherical building blocks. These clusters present ideal model systems to study the motion of objects with complex shape. Because they could be separated into fractions of well-defined configurations on a sufficient scale and their overall dimensions were below 300 nm, the translational and rotational Diffusion coefficients of particle duplets, triplets and tetrahedrons could be determined by a combination of polarized dynamic light scattering (DLS) and depolarized dynamic light scattering (DDLS). The use of colloidal clusters for DDLS experiments overcomes the limitation of earlier experiments on the Diffusion of complex objects near surfaces because the true 3D Diffusion can be studied. When the exact geometry of the complex assemblies is known, different hydrodynamic models for calculating the Diffusion coefficient for objects with complex shapes could be applied. Because hydrodynamic friction must be restricted to the cluster surface the so-called shell model, in which the surface is represented as a shell of small friction elements, was most suitable to describe the dynamics. A quantitative comparison of the predictions from theoretical modeling with the results obtained by DDLS showed an excellent agreement between experiment and theory.
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3d Brownian Diffusion of submicron sized particle clusters
ACS Nano, 2009Co-Authors: Martin Hoffmann, Claudia Simone Wagner, Ludger Harnau, Alexander WittemannAbstract:We report on the translation and rotation of particle clusters made through the combination of spherical building blocks. These clusters present ideal model systems to study the motion of objects with complex shape. Since they could be separated into fractions of well-defined configurations on a sufficient scale and because their overall dimensions were below 300 nm, the translational and rotational Diffusion coefficients of particle doublets, triplets, and tetrahedrons could be determined by a combination of polarized dynamic light scattering (DLS) and depolarized dynamic light scattering (DDLS). The use of colloidal clusters for DDLS experiments overcomes the limitation of earlier experiments on the Diffusion of complex objects near surfaces because the true 3D Diffusion can be studied. When the exact geometry of the complex assemblies is known, different hydrodynamic models for calculating the Diffusion coefficients for objects with complex shapes could be applied. Because hydrodynamic friction must be restricted to the cluster surface, the so-called shell model, in which the surface is represented as a shell of small friction elements, was most suitable to describe the dynamics. A quantitative comparison of the predictions from theoretical modeling with the results obtained by DDLS showed an excellent agreement between experiment and theory.
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3d Brownian Diffusion of submicron sized particle clusters
ACS Nano, 2009Co-Authors: Martin Hoffmann, Claudia Simone Wagner, Ludger Harnau, Alexander WittemannAbstract:We report on the translation and rotation of particle clusters made through the combination of spherical building blocks. These clusters present ideal model systems to study the motion of objects with complex shape. Since they could be separated into fractions of well-defined configurations on a sufficient scale and because their overall dimensions were below 300 nm, the translational and rotational Diffusion coefficients of particle doublets, triplets, and tetrahedrons could be determined by a combination of polarized dynamic light scattering (DLS) and depolarized dynamic light scattering (DDLS). The use of colloidal clusters for DDLS experiments overcomes the limitation of earlier experiments on the Diffusion of complex objects near surfaces because the true 3D Diffusion can be studied. When the exact geometry of the complex assemblies is known, different hydrodynamic models for calculating the Diffusion coefficients for objects with complex shapes could be applied. Because hydrodynamic friction must be...
