The present paper focuses on finding an analytical solution for fully developed third-grade non-Newtonian fluids flows inside rough circular pipes at low Reynolds numbers(Stokes flows).The wall roughness is modeled by...The present paper focuses on finding an analytical solution for fully developed third-grade non-Newtonian fluids flows inside rough circular pipes at low Reynolds numbers(Stokes flows).The wall roughness is modeled by two different periodic morphologies based on sinusoidal and triangular geometries.In this study,the relative roughness(ratio of the roughness amplitude to the pipe hydraulic diameter)is selected to be a small value,which is appropriate for the perturbation analysis.The governing parameters including the axial and radial velocity profiles,stream function,wall shear stress,pressure gradient,and friction factor are expressed in analytical formulas and they are compared to the smooth pipe.The effect of the relative roughness,the wall wave number,and the non-Newtonian parameter on the governing parameters are investigated.The results show that modeling the roughness by triangular geometry has a better prediction of pressure drop regarding the basic solution of the smooth pipe.展开更多
In this paper, a non-Newtonian third-grade blood in coronary and femoral arteries is simulated analytically and numerically. The blood is considered as the third- grade non-Newtonian fluid under the periodic body acce...In this paper, a non-Newtonian third-grade blood in coronary and femoral arteries is simulated analytically and numerically. The blood is considered as the third- grade non-Newtonian fluid under the periodic body acceleration motion and the pulsatile pressure gradient. The hybrid multi-step differential transformation method （Hybrid-Ms- DTM） and the Crank-Nicholson method （CNM） are used to solve the partial differential equation （PDE）, and a good agreement between them is observed in the results. The effects of the some physical parameters such as the amplitude, the lead angle, and the body acceleration frequency on the velocity and shear stress profiles are considered. The results show that increasing the amplitude, Ag, and reducing the lead angle of body acceleration, 9, make higher velocity profiles on the center line of both arteries. Also, the maximum wall shear stress increases when Ag increases.展开更多
The Cattaneo-Christov heat flux in the two-dimensional （2D） flow of a third- grade fluid towards an exponentially stretching sheet is investigated. The energy equation is considered through thermal relaxation. Simil...The Cattaneo-Christov heat flux in the two-dimensional （2D） flow of a third- grade fluid towards an exponentially stretching sheet is investigated. The energy equation is considered through thermal relaxation. Similarity transformations are accounted to obtain the ordinary differential systems. The converted non-dimensional equations are solved for the series solutions. The convergence analysis of the computed solutions is reported. The graphical results of the velocity and temperature profiles are plotted and elaborated in detail. The results show that the thermal relaxation enhances the temper- ature gradient while reduces the temperature profile.展开更多
This study is devoted to the investigation of thermal criticality for a reactive gravity driven thin film flow of a third-grade fluid with adiabatic free surface down an inclined isothermal plane. It is assumed that t...This study is devoted to the investigation of thermal criticality for a reactive gravity driven thin film flow of a third-grade fluid with adiabatic free surface down an inclined isothermal plane. It is assumed that the reaction is exothermic under Arrhenius kinetics, neglecting the consumption of the material. The governing non-linear equations for conservation of momentum and energy are obtained and solved by using a new computational approach based on a special type of Hermite-Padé approximation technique implemented in MAPLE. This semi-numerical scheme offers some advantages over solutions obtained with traditional methods such as finite differences, spectral method, and shooting method. It reveals the analytical structure of the solution function. Important properties of overall flow structure including velocity field, temperature field, thermal criticality, and bifurcations are discussed.展开更多
The well-known problem of unidirectional plane flow of a fluid in a non-porous half-space due to the impulsive motion of the rigid plane wall it rests upon is discussed in the context of an unsteady MHD third-grade fl...The well-known problem of unidirectional plane flow of a fluid in a non-porous half-space due to the impulsive motion of the rigid plane wall it rests upon is discussed in the context of an unsteady MHD third-grade fluid in presence of Hall currents. The governing non-linear partial differential equations describing the problem are converted to a system of non-linear ordinary differential equations by using the similarity transformations. The complex analytical solution is found by using the homotopy analysis method (HAM). The existing literature on the topic shows that it is the first study regarding the effects of Hall current on flow of an unsteady MHD third-grade fluid over an impulsively moving plane wall. The convergence of the obtained complex series solutions is carefully analyzed. The effects of dimensionless parameters on the velocity are illustrated through plots and the effects of the pertinent parameters on the local skin friction coefficient at the surface of the wall are presented numerically in tabular form.展开更多
Neglecting the consumption of the material, a steady incompressible flow of an exothermic reacting third-grade fluid with viscous heating in a circular cylindrical pipe is numerically studied for both cases of constan...Neglecting the consumption of the material, a steady incompressible flow of an exothermic reacting third-grade fluid with viscous heating in a circular cylindrical pipe is numerically studied for both cases of constant viscosity and Reynolds＇ viscosity model. The coupled ordinary differential equations governing the flow in cylindrical coordinates, are transformed into dimensionless forms using appropriate transformations, and then solved numerically. Solutions using Maple are presented in tabular form and given in terms of dimensionless central fluid velocity and temperature, skin friction and heat transfer rate for three parametric values in the Reynolds＇ case. The numerical results for the velocity and temperature fields are also presented through graphs. Bifurcations are discussed using shooting method. Comparisons are also made between the present results and those of previous work, and thus verify the validity of the provided numerical solutions. Important properties of thermal criticality are provided for variable viscosity parameter and reaction order. Further numerical results are presented in the form of tables and graphs for transition of physical parameters, while varying certain flow and fluid material parameters. Also, the flow behaviour of the reactive fluid of third-grade is compared with those of the Newtonian reactive fluid.展开更多
建设区域医疗中心是国家“十四五”规划的重要内容,是协同推进公立医院医、教、研、防、管整体水平提升的重要途径。深入了解全国区域医疗中心申报和建设情况,探讨其申报和建设过程中面临的困境及解决方案,积极推动地级市三甲医院高质...建设区域医疗中心是国家“十四五”规划的重要内容,是协同推进公立医院医、教、研、防、管整体水平提升的重要途径。深入了解全国区域医疗中心申报和建设情况,探讨其申报和建设过程中面临的困境及解决方案,积极推动地级市三甲医院高质量发展。采用态势分析法(strengths,weaknesses,opportunities and threats analysis,SWTO),从4个维度分析案例医院的内部优势、劣势、外部机会、挑战,探索地级市公立医院成功申报国家区域医疗中心的路径策略。地级市三甲医院申报区域医疗中心面临诸多困难和挑战,医院申报积极性高,牵头医院在人才、技术等方面做了充分准备,但也存在申报和建设等诸多问题,层次和结构需进一步优化、运行机制有待进一步健全、医疗服务同质化水平有待进一步提高等问题。建议政府做好资源规划,引导医院重视申报工作,强化人才培养和专科诊疗能力水平,发挥信息化支撑作用,顺利实现国家区域医疗中心的成功申报。展开更多
文摘The present paper focuses on finding an analytical solution for fully developed third-grade non-Newtonian fluids flows inside rough circular pipes at low Reynolds numbers(Stokes flows).The wall roughness is modeled by two different periodic morphologies based on sinusoidal and triangular geometries.In this study,the relative roughness(ratio of the roughness amplitude to the pipe hydraulic diameter)is selected to be a small value,which is appropriate for the perturbation analysis.The governing parameters including the axial and radial velocity profiles,stream function,wall shear stress,pressure gradient,and friction factor are expressed in analytical formulas and they are compared to the smooth pipe.The effect of the relative roughness,the wall wave number,and the non-Newtonian parameter on the governing parameters are investigated.The results show that modeling the roughness by triangular geometry has a better prediction of pressure drop regarding the basic solution of the smooth pipe.
文摘In this paper, a non-Newtonian third-grade blood in coronary and femoral arteries is simulated analytically and numerically. The blood is considered as the third- grade non-Newtonian fluid under the periodic body acceleration motion and the pulsatile pressure gradient. The hybrid multi-step differential transformation method （Hybrid-Ms- DTM） and the Crank-Nicholson method （CNM） are used to solve the partial differential equation （PDE）, and a good agreement between them is observed in the results. The effects of the some physical parameters such as the amplitude, the lead angle, and the body acceleration frequency on the velocity and shear stress profiles are considered. The results show that increasing the amplitude, Ag, and reducing the lead angle of body acceleration, 9, make higher velocity profiles on the center line of both arteries. Also, the maximum wall shear stress increases when Ag increases.
文摘The Cattaneo-Christov heat flux in the two-dimensional （2D） flow of a third- grade fluid towards an exponentially stretching sheet is investigated. The energy equation is considered through thermal relaxation. Similarity transformations are accounted to obtain the ordinary differential systems. The converted non-dimensional equations are solved for the series solutions. The convergence analysis of the computed solutions is reported. The graphical results of the velocity and temperature profiles are plotted and elaborated in detail. The results show that the thermal relaxation enhances the temper- ature gradient while reduces the temperature profile.
基金supported by the National Research Foundation of South Africa Thuthuka Programme
文摘This study is devoted to the investigation of thermal criticality for a reactive gravity driven thin film flow of a third-grade fluid with adiabatic free surface down an inclined isothermal plane. It is assumed that the reaction is exothermic under Arrhenius kinetics, neglecting the consumption of the material. The governing non-linear equations for conservation of momentum and energy are obtained and solved by using a new computational approach based on a special type of Hermite-Padé approximation technique implemented in MAPLE. This semi-numerical scheme offers some advantages over solutions obtained with traditional methods such as finite differences, spectral method, and shooting method. It reveals the analytical structure of the solution function. Important properties of overall flow structure including velocity field, temperature field, thermal criticality, and bifurcations are discussed.
文摘The well-known problem of unidirectional plane flow of a fluid in a non-porous half-space due to the impulsive motion of the rigid plane wall it rests upon is discussed in the context of an unsteady MHD third-grade fluid in presence of Hall currents. The governing non-linear partial differential equations describing the problem are converted to a system of non-linear ordinary differential equations by using the similarity transformations. The complex analytical solution is found by using the homotopy analysis method (HAM). The existing literature on the topic shows that it is the first study regarding the effects of Hall current on flow of an unsteady MHD third-grade fluid over an impulsively moving plane wall. The convergence of the obtained complex series solutions is carefully analyzed. The effects of dimensionless parameters on the velocity are illustrated through plots and the effects of the pertinent parameters on the local skin friction coefficient at the surface of the wall are presented numerically in tabular form.
基金supported by Pastor E. A. Adeboye endowed Professorial Chair and conducted at the Department of Mathematics, University of Lagos, Lagos, Nigeria while on leave from
文摘Neglecting the consumption of the material, a steady incompressible flow of an exothermic reacting third-grade fluid with viscous heating in a circular cylindrical pipe is numerically studied for both cases of constant viscosity and Reynolds＇ viscosity model. The coupled ordinary differential equations governing the flow in cylindrical coordinates, are transformed into dimensionless forms using appropriate transformations, and then solved numerically. Solutions using Maple are presented in tabular form and given in terms of dimensionless central fluid velocity and temperature, skin friction and heat transfer rate for three parametric values in the Reynolds＇ case. The numerical results for the velocity and temperature fields are also presented through graphs. Bifurcations are discussed using shooting method. Comparisons are also made between the present results and those of previous work, and thus verify the validity of the provided numerical solutions. Important properties of thermal criticality are provided for variable viscosity parameter and reaction order. Further numerical results are presented in the form of tables and graphs for transition of physical parameters, while varying certain flow and fluid material parameters. Also, the flow behaviour of the reactive fluid of third-grade is compared with those of the Newtonian reactive fluid.
文摘建设区域医疗中心是国家“十四五”规划的重要内容,是协同推进公立医院医、教、研、防、管整体水平提升的重要途径。深入了解全国区域医疗中心申报和建设情况,探讨其申报和建设过程中面临的困境及解决方案,积极推动地级市三甲医院高质量发展。采用态势分析法(strengths,weaknesses,opportunities and threats analysis,SWTO),从4个维度分析案例医院的内部优势、劣势、外部机会、挑战,探索地级市公立医院成功申报国家区域医疗中心的路径策略。地级市三甲医院申报区域医疗中心面临诸多困难和挑战,医院申报积极性高,牵头医院在人才、技术等方面做了充分准备,但也存在申报和建设等诸多问题,层次和结构需进一步优化、运行机制有待进一步健全、医疗服务同质化水平有待进一步提高等问题。建议政府做好资源规划,引导医院重视申报工作,强化人才培养和专科诊疗能力水平,发挥信息化支撑作用,顺利实现国家区域医疗中心的成功申报。
