The two-dimensional non-Newtonian steady flow on a power-law stretched surface with suction or injection is studied. Thermal conductivity is assumed to vary as a linear function of temperature. The transformed governi...The two-dimensional non-Newtonian steady flow on a power-law stretched surface with suction or injection is studied. Thermal conductivity is assumed to vary as a linear function of temperature. The transformed governing equations in the present study are solved numerically using the Runge-Kutta method. Through a comparison, results for a special case of the problem show excellent agreement with those in a previous work. Two cases are considered, one corresponding to a cooled surface temperature and the other to a uniform surface temperature. Numerical results show that the thermal conductivity variation parameter, the injection parameter, and the power-law index have significant influences on the temperature profiles and the Nusselt number.展开更多
This article concentrates on the properties of three-dimensional magneto-hydrodynamic flow of a viscous fluid saturated with Darcy porous medium deformed by a nonlinear variable thickened surface.Analysis of flow is d...This article concentrates on the properties of three-dimensional magneto-hydrodynamic flow of a viscous fluid saturated with Darcy porous medium deformed by a nonlinear variable thickened surface.Analysis of flow is disclosed in the neighborhood of stagnation point.Features of heat transport are characterized with Newtonian heating and variable thermal conductivity.Mass transport is carried out with first order chemical reaction and variable mass diffusivity.Resulting governing equations are transformed by implementation of appropriate transformations.Analytical convergent series solutions are computed via homotopic technique.Physical aspects of numerous parameters are discussed through graphical data.Drag force coefficient,Sherwood and Nusselt numbers are illustrated through graphs corresponding to various pertinent parameters.Graphical discussion reveals that conjugate and constructive chemical reaction parameters enhance the temperature and concentration distributions,respectively.展开更多
A novel numerical method to lubricate a conventional finite diameterconical-cylindrical bearing with a non-Newtonian lubricant, while adhering to the power-law model,is presented. The elastic deformation of bearing an...A novel numerical method to lubricate a conventional finite diameterconical-cylindrical bearing with a non-Newtonian lubricant, while adhering to the power-law model,is presented. The elastic deformation of bearing and varied viscosity of lubrication due to thepressure distribution of film thickness are also considered. Simulation results indicate that thenormal load carrying capacity is more pronounced for higher values of flow behavior index n, highereccentricity ratios and larger misalignment factors. It is found that the viscosity-pressure to theeffect of lubricant viscosity is significant.展开更多
For a generalized quasi-Newtonian flow, a new stabilized method focused on the low-order velocity-pressure pairs, （bi）linear/（bi）linear and （bi）linear/constant element, is presented. The pressure projection stab...For a generalized quasi-Newtonian flow, a new stabilized method focused on the low-order velocity-pressure pairs, （bi）linear/（bi）linear and （bi）linear/constant element, is presented. The pressure projection stabilized method is extended from Stokes problems to quasi-Newtonian flow problems. The theoretical framework developed here yields an estimate bound, which measures error in the approximate velocity in the W 1,r（Ω） norm and that of the pressure in the L r＇ （Ω） （1/r ＋ 1/r＇ = 1）. The power law model and the Carreau model are special ones of the quasi-Newtonian flow problem discussed in this paper. Moreover, a residual-based posterior bound is given. Numerical experiments are presented to confirm the theoretical results.展开更多
This article aims to numerically investigate the flow pattern for Newtonian and power law non-Newtonian fluid in a semi-half circular channel with corrugated walls under the influence of a magnetic field. The results ...This article aims to numerically investigate the flow pattern for Newtonian and power law non-Newtonian fluid in a semi-half circular channel with corrugated walls under the influence of a magnetic field. The results indicate that, presence of a magnetic field affects the flow field in several aspects, especially in the vortex creation and dissipation. In addition, the analysis is carried out for different Reynolds numbers to ascertain the influence of magnetic field on each flow regime. Eventually, the analysis is carried out for a range of power indices including pseudo plastic (shear-thinning) to dilatants (shear-thickening) fluids. The results show that by increasing the power-index, the vortices begin to form and grow gradually so that in the shear-thickening fluid an extra vortex is formed and created nearby the corrugated part of the channel.展开更多
In this paper, the power-law model for a non-Newtonian (pseudo-plastic) flow is investigated numerically. The D2Q9 model of Lattice Boltzmann method is used to simulate the micro-channel flow with expansion geometries...In this paper, the power-law model for a non-Newtonian (pseudo-plastic) flow is investigated numerically. The D2Q9 model of Lattice Boltzmann method is used to simulate the micro-channel flow with expansion geometries. This geometry is made by two squared or trapezoid cavities at the bottom and top of the channel which can simulate an artery with local expansion. The cavities are displaced along the channel and the effects of the displacements are investigated for inline structures and staggered ones (anti-symmetric expansion). The method is validated by a Poiseuille flow of the power-law fluid in a duct. Validation is performed for two cases: The Newtonian fluid and the shear thinning fluid (pseudo-plastic) with n = 0.5. The results are discussed in four parts: 1) Pressure drop;It is shown that the pressure drop along the channel for inline cavities is much more than the pressure drop along the staggered structures. 2) Velocity profiles;the velocity profiles are sketched at the centerline of the cavities. The effects of pseudo-plasticity are discussed. 3) Shear stress distribution;the shear stress is computed and shown in the domain. The Newtonian and non-Newto- nian fluids are discussed and the effect of the power n on shear stress is argued. 4) Generated vortices in the cavities are also presented. The shape of the vortices is depicted for various cases. The results for these cases are talked over and it is found that the vortices will be removed for flows with n smaller than 0.5.展开更多
This paper .Studies power law no-Newtonian fluid rotative flow. in an annularpipe. The governing equation is nonlinear one, we linearized the governing equationby assuming that partial factor is at state. With Lapla...This paper .Studies power law no-Newtonian fluid rotative flow. in an annularpipe. The governing equation is nonlinear one, we linearized the governing equationby assuming that partial factor is at state. With Laplace transform we obtain ananalytical solution of the problem In the paper several groups of curves are given.these curves reflect the temporal change law and. spatial distribution of fluid velocity.In addition.we study the effection of power law index on the flow field the resultindicates that when the power law index n < l. the flow velocity is highly sensitive tothe index. and this fact is importanl in related engineering decisions.展开更多
文摘The two-dimensional non-Newtonian steady flow on a power-law stretched surface with suction or injection is studied. Thermal conductivity is assumed to vary as a linear function of temperature. The transformed governing equations in the present study are solved numerically using the Runge-Kutta method. Through a comparison, results for a special case of the problem show excellent agreement with those in a previous work. Two cases are considered, one corresponding to a cooled surface temperature and the other to a uniform surface temperature. Numerical results show that the thermal conductivity variation parameter, the injection parameter, and the power-law index have significant influences on the temperature profiles and the Nusselt number.
文摘This article concentrates on the properties of three-dimensional magneto-hydrodynamic flow of a viscous fluid saturated with Darcy porous medium deformed by a nonlinear variable thickened surface.Analysis of flow is disclosed in the neighborhood of stagnation point.Features of heat transport are characterized with Newtonian heating and variable thermal conductivity.Mass transport is carried out with first order chemical reaction and variable mass diffusivity.Resulting governing equations are transformed by implementation of appropriate transformations.Analytical convergent series solutions are computed via homotopic technique.Physical aspects of numerous parameters are discussed through graphical data.Drag force coefficient,Sherwood and Nusselt numbers are illustrated through graphs corresponding to various pertinent parameters.Graphical discussion reveals that conjugate and constructive chemical reaction parameters enhance the temperature and concentration distributions,respectively.
文摘A novel numerical method to lubricate a conventional finite diameterconical-cylindrical bearing with a non-Newtonian lubricant, while adhering to the power-law model,is presented. The elastic deformation of bearing and varied viscosity of lubrication due to thepressure distribution of film thickness are also considered. Simulation results indicate that thenormal load carrying capacity is more pronounced for higher values of flow behavior index n, highereccentricity ratios and larger misalignment factors. It is found that the viscosity-pressure to theeffect of lubricant viscosity is significant.
基金Project supported by the Key Technology Research and Development Program of Sichuan Province of China(No.05GG006-006-2)
文摘For a generalized quasi-Newtonian flow, a new stabilized method focused on the low-order velocity-pressure pairs, （bi）linear/（bi）linear and （bi）linear/constant element, is presented. The pressure projection stabilized method is extended from Stokes problems to quasi-Newtonian flow problems. The theoretical framework developed here yields an estimate bound, which measures error in the approximate velocity in the W 1,r（Ω） norm and that of the pressure in the L r＇ （Ω） （1/r ＋ 1/r＇ = 1）. The power law model and the Carreau model are special ones of the quasi-Newtonian flow problem discussed in this paper. Moreover, a residual-based posterior bound is given. Numerical experiments are presented to confirm the theoretical results.
文摘This article aims to numerically investigate the flow pattern for Newtonian and power law non-Newtonian fluid in a semi-half circular channel with corrugated walls under the influence of a magnetic field. The results indicate that, presence of a magnetic field affects the flow field in several aspects, especially in the vortex creation and dissipation. In addition, the analysis is carried out for different Reynolds numbers to ascertain the influence of magnetic field on each flow regime. Eventually, the analysis is carried out for a range of power indices including pseudo plastic (shear-thinning) to dilatants (shear-thickening) fluids. The results show that by increasing the power-index, the vortices begin to form and grow gradually so that in the shear-thickening fluid an extra vortex is formed and created nearby the corrugated part of the channel.
文摘In this paper, the power-law model for a non-Newtonian (pseudo-plastic) flow is investigated numerically. The D2Q9 model of Lattice Boltzmann method is used to simulate the micro-channel flow with expansion geometries. This geometry is made by two squared or trapezoid cavities at the bottom and top of the channel which can simulate an artery with local expansion. The cavities are displaced along the channel and the effects of the displacements are investigated for inline structures and staggered ones (anti-symmetric expansion). The method is validated by a Poiseuille flow of the power-law fluid in a duct. Validation is performed for two cases: The Newtonian fluid and the shear thinning fluid (pseudo-plastic) with n = 0.5. The results are discussed in four parts: 1) Pressure drop;It is shown that the pressure drop along the channel for inline cavities is much more than the pressure drop along the staggered structures. 2) Velocity profiles;the velocity profiles are sketched at the centerline of the cavities. The effects of pseudo-plasticity are discussed. 3) Shear stress distribution;the shear stress is computed and shown in the domain. The Newtonian and non-Newto- nian fluids are discussed and the effect of the power n on shear stress is argued. 4) Generated vortices in the cavities are also presented. The shape of the vortices is depicted for various cases. The results for these cases are talked over and it is found that the vortices will be removed for flows with n smaller than 0.5.
文摘This paper .Studies power law no-Newtonian fluid rotative flow. in an annularpipe. The governing equation is nonlinear one, we linearized the governing equationby assuming that partial factor is at state. With Laplace transform we obtain ananalytical solution of the problem In the paper several groups of curves are given.these curves reflect the temporal change law and. spatial distribution of fluid velocity.In addition.we study the effection of power law index on the flow field the resultindicates that when the power law index n < l. the flow velocity is highly sensitive tothe index. and this fact is importanl in related engineering decisions.
