The present study inspects the non-aligned stagnation point nano fluid over a convective surface in the presence of partial slip. Two types of base fluids namely water and kerosene are selected with Cu nanoparticles. ...The present study inspects the non-aligned stagnation point nano fluid over a convective surface in the presence of partial slip. Two types of base fluids namely water and kerosene are selected with Cu nanoparticles. The governing physical problem is presented and transformed into a system of coupled nonlinear differential equations using suitable similarity transformations. These equations are then solved numerically using midpoint integration scheme along with Richardson extrapolation via Maple. Impact of relevant physical parameters on the dimensionless velocity and temperature profiles are portrayed through graphs. Physical quantities such as local skin frictions co-efficient and Nusselt numbers are tabularized.It is detected from numerical computations that kerosene-based nano fluids have better heat transfer capability compared with water-based nanofluids. Moreover it is found that water-based nanofluids offer less resistance in terms of skin friction than kerosene-based fluid. In order to authenticate our present study, the calculated results are compared with the prevailing literature and a considerable agreement is perceived for the limiting case.展开更多
The surface oxidation and subsurface microstructure evolution of Alloy 690 TT can occur during partial slip fretting corrosion in high-temperature pure water.Detailed characterization methods such as laser scanning co...The surface oxidation and subsurface microstructure evolution of Alloy 690 TT can occur during partial slip fretting corrosion in high-temperature pure water.Detailed characterization methods such as laser scanning confocal microscopy,scanning electron microscopy,electron probe micro-analyzer,and transmission electron microscopy were used to reveal the related mechanism.The results showed that Cr_(2)O_(3) oxides together with a small number of spinel oxides were formed in sticking region since a small quantity of high-temperature water could pass through the gaps between the asperities to oxidize the materials.Widespread distribution of oxides in microslip region consisted of(Ni,Fe)Cr_(2)O_(4),because Ni^(2+)and Fe^(2+) ions could react with Cr_(2)O_(3) to generate a small amount of non-stoichiometric spinel oxides.The oxides around micropitting in microslip region consisted of double-layer structure.The outermost layer contained(Fe,Cr)-rich oxides due to the effect of fretting leading to mechanical mixing between Cr_(2)O_(3) and(Ni,Fe)(Fe,Cr)_(2)O_(4).The inner layer consisted of(Fe,Ni)-rich oxides owing to the consumption of Cr_(2)O_(3) by the reaction with Ni^(2+)and Fe^(2+) ions.The reciprocating motion of oxide particles in microslip region resulted in the stress-strain supporting the recrystallization for the formation and development of a tribologically transformed structure in subsurface and plowing effect by fretting in surface.展开更多
A numerical study of partial slip boundary condition is investigated. The stagnation-point flow problem involving some physio-chemical parameters has been elucidated. The process involves developing a multivariate mat...A numerical study of partial slip boundary condition is investigated. The stagnation-point flow problem involving some physio-chemical parameters has been elucidated. The process involves developing a multivariate mathematical model for the flow and transforming it into a coupled univariate equation. Key parameters of interest in the study are the buoyancy force, the surface stretching, the unsteadiness, the radiation, the dissipation effects, the slip effects, the species reaction and the magnetic field parameters. It is concluded that the impact of physio-chemical factors significantly alters the kinematics of the flow in order to optimally achieve desired product characteristics.展开更多
This paper is an analytical study of the rotating flow of a third grade fluid past a porous plate with partial slip effects. It serves as a flow model for the study of polymers. The analytic solution has been determin...This paper is an analytical study of the rotating flow of a third grade fluid past a porous plate with partial slip effects. It serves as a flow model for the study of polymers. The analytic solution has been determined using homotopy analysis method （HAM）.展开更多
The study investigates the partial slip contact problem between thermoelectric material and periodic punches including flat and cylindrical punches under various loading conditions,including normal force,energy flux,a...The study investigates the partial slip contact problem between thermoelectric material and periodic punches including flat and cylindrical punches under various loading conditions,including normal force,energy flux,and electric current density.When developing and enhancing thermoelectric devices intended for energy harvesting and temperature regulation,the relationship between punch geometry and thermoelectric material plays a crucial role.The periodic contact problem leads to the formation of a singular integral equation with a Hilbert kernel,distinguishing it from the traditional Cauchy kernel.It delves into the impact of the thermo-electric-mechanical coupling effect on the evolution of stick-slip zone length and contact stress during partial slip.By formulating the current nonlinear problem into a set of singular integral equations,the study identifies primary variables,including normal and tangential contact stresses,as well as slip and stick zones.The partial contact problem is further simplified by applying the Goodman approximation,enabling an iterative approach to determine the stick-slip zone,contact zone size,and stress distribution.Notably,the research reveals that factors such as the shape of the punch,the coefficient of friction,and TE parameters significantly influence stress strength and the characteristics of the stick-slip zone.展开更多
In thermofluid systems,the lid-driven square chamber plays an imperative role in analyzing thermodynamics’first and second laws in limited volume cases executed by sheer effects with a prominent role in many industri...In thermofluid systems,the lid-driven square chamber plays an imperative role in analyzing thermodynamics’first and second laws in limited volume cases executed by sheer effects with a prominent role in many industrial applications including electronic cooling,heat exchangers,microfluidic components,solar collectors,and renewable energies.Furthermore,nanofluids as working fluids have demonstrated potential for heat transfer enhancement systems,however there are some concerns about irreversibility problems in the systems.Due to this problem and in line with the applications of partial slip on fluid flow modification and irreversibilities,the present study considers laminar mixed convection and entropy generation analysis of aluminum oxide nanofluid inside a lid-driven wavy cavity having an internal conductive solid body in the presence of a partial slip on the upper surface,which to the best of our knowledge,has not been investigated so far.The fundamental equations of the current work with the appropriate boundary conditions are first made dimensionless and then solved numerically using the Galerkin weighted residual FEM.The main parameters of the flow and heat transfer,entropy generation,and Bejan number are presented and explained in details.The outcomes indicate that the partial slip is more effective when friction irreversibilities govern the cavity.In the presence of slip condition,the flow circulation changes the trend in the middle of the cavity around the solid block leading to a decrease in the isentropic lines at the dense sections with almost 30%less than the case of no-slip condition.It is concluded that partial slip shows different trends on the local Nusselt number interface along the wavy wall improving the average Nusselt number where high friction irreversibilities dominate.展开更多
The flow and heat transfer of an electrically conducting non-Newtonian second grade fluid due to a radially stretching surface with partial slip is considered. The partial slip is controlled by a dimensionless slip fa...The flow and heat transfer of an electrically conducting non-Newtonian second grade fluid due to a radially stretching surface with partial slip is considered. The partial slip is controlled by a dimensionless slip factor, which varies between zero （total adhesion） and infinity （full slip）. Suitable similarity transformations are used to reduce the resulting highly nonlinear partial differential equations into ordinary differential equations. The issue of paucity of boundary conditions is addressed and an effective numerical scheme is adopted to solve the obtained differential equations even without augmenting any extra boundary conditions. The important findings in this communication are the combined effects of the partial slip, magnetic interaction parameter and the second grade fluid parameter on the velocity and temperature fields. It is interesting to find that the slip increases the momentum and thermal boundary layer thickness. As the slip increases in magnitude, permitting more fluid to slip past the sheet, the skin friction coefficient decreases in magnitude and approaches zero for higher values of the slip parameter, i.e., the fluid behaves as though it were inviscid. The presence of a magnetic field has also substantial effects on velocity and temperature fields.展开更多
This investigation deals with the effects of slip, magnetic field, and non- Newtonian flow parameters on the flow and heat transfer of an incompressible, electrically conducting fourth-grade fluid past an infinite por...This investigation deals with the effects of slip, magnetic field, and non- Newtonian flow parameters on the flow and heat transfer of an incompressible, electrically conducting fourth-grade fluid past an infinite porous plate. The heat transfer analysis is carried out for two heating processes. The system of highly non-linear differential equations is solved by the shooting method with the fourth-order Runge-Kutta method for moderate values of the parameters. The effective Broyden technique is adopted in order to improve the initial guesses and to satisfy the boundary conditions at infinity. An exceptional cross-over is obtained in the velocity profile in the presence of slip. The fourth-grade fluid parameter is found to increase the momentum boundary layer thickness, whereas the slip parameter substantially decreases it. Similarly, the non-Newtonian fluid parameters and the slip have opposite effects on the thermal boundary layer thickness.展开更多
In this paper, we examine the unsteady magneto hydrodynamic (MHD) flow generated by a disc that is making non-coaxial rotations with a third grade fluid at infinity and moving with a variable acceleration. The fluid i...In this paper, we examine the unsteady magneto hydrodynamic (MHD) flow generated by a disc that is making non-coaxial rotations with a third grade fluid at infinity and moving with a variable acceleration. The fluid is assumed to satisfy slip boundary condition on the disc. The governing equations are three dimensional and highly non-linear in nature. The assumed slip boundary condition is non-linear as well. The governing equations are transformed to a nonlinear boundary value problem which is solved numerically. Comparison of this generalized problem with uniformly accelerated disk satisfying no slip condition is made. Variations of the characterizing dimensionless parameters such as slip parameter λ, acceleration parameter c, unsteady parameter τ, third grade parameter β, suction parameter S, and magnetic parameter N on the flow field are discussed and analyzed graphically.展开更多
The strain difference of steel and concrete under vertical concentrated load was analyzed on the basis of elastic theory, and was compared with ideal solution of steel and concrete under vertical uniform load. The res...The strain difference of steel and concrete under vertical concentrated load was analyzed on the basis of elastic theory, and was compared with ideal solution of steel and concrete under vertical uniform load. The results indicate that the computing formula concluded from the paper is believable. The practical structure usually bears concentrated load, so it can be used in the practical engineering.展开更多
With co-seismic surface rupture slip displacements provided by the field observation for the 2001 MS8.1 West Kunlun Mountain Pass earthquake, this paper estimates the rupture speed on the main faulting segment with a ...With co-seismic surface rupture slip displacements provided by the field observation for the 2001 MS8.1 West Kunlun Mountain Pass earthquake, this paper estimates the rupture speed on the main faulting segment with a long straight fault trace on the surface based on a simple slip-weakening rupture model, in which the frictional overshoot or undershoot are involved in consideration of energy partition during the earthquake faulting. In contrast to the study of Bouchon and Vallée, in which the rupture propagation along the main fault could exceed the local shear-wave speed, perhaps reach the P-wave speed on a certain section of fault, our results show that, under a slip-weakening assumption combined with a frictional undershoot (partial stress drop model), average rupture speed should be equal to or less than the Rayleigh wave speed with a high seismic radiation efficiency, which is consistent with the result derived by waveform inversion and the result estimated from source stress field. Associated with the surface rupture mechanism, such as partial stress drop (frictional undershoot) associated with the apparent stress, an alternative rupture mechanism based on the slip-weakening model has also been discussed.展开更多
文摘The present study inspects the non-aligned stagnation point nano fluid over a convective surface in the presence of partial slip. Two types of base fluids namely water and kerosene are selected with Cu nanoparticles. The governing physical problem is presented and transformed into a system of coupled nonlinear differential equations using suitable similarity transformations. These equations are then solved numerically using midpoint integration scheme along with Richardson extrapolation via Maple. Impact of relevant physical parameters on the dimensionless velocity and temperature profiles are portrayed through graphs. Physical quantities such as local skin frictions co-efficient and Nusselt numbers are tabularized.It is detected from numerical computations that kerosene-based nano fluids have better heat transfer capability compared with water-based nanofluids. Moreover it is found that water-based nanofluids offer less resistance in terms of skin friction than kerosene-based fluid. In order to authenticate our present study, the calculated results are compared with the prevailing literature and a considerable agreement is perceived for the limiting case.
基金financial supports of the Beijing Natural Science Foundation(Grant No.2194081)the Project funded by China Postdoctoral Science Foundation(Grant No.2018M641187)the Fundamental Research Funds for the Central Universities(Grant No.FRF-TP-18-047A1)。
文摘The surface oxidation and subsurface microstructure evolution of Alloy 690 TT can occur during partial slip fretting corrosion in high-temperature pure water.Detailed characterization methods such as laser scanning confocal microscopy,scanning electron microscopy,electron probe micro-analyzer,and transmission electron microscopy were used to reveal the related mechanism.The results showed that Cr_(2)O_(3) oxides together with a small number of spinel oxides were formed in sticking region since a small quantity of high-temperature water could pass through the gaps between the asperities to oxidize the materials.Widespread distribution of oxides in microslip region consisted of(Ni,Fe)Cr_(2)O_(4),because Ni^(2+)and Fe^(2+) ions could react with Cr_(2)O_(3) to generate a small amount of non-stoichiometric spinel oxides.The oxides around micropitting in microslip region consisted of double-layer structure.The outermost layer contained(Fe,Cr)-rich oxides due to the effect of fretting leading to mechanical mixing between Cr_(2)O_(3) and(Ni,Fe)(Fe,Cr)_(2)O_(4).The inner layer consisted of(Fe,Ni)-rich oxides owing to the consumption of Cr_(2)O_(3) by the reaction with Ni^(2+)and Fe^(2+) ions.The reciprocating motion of oxide particles in microslip region resulted in the stress-strain supporting the recrystallization for the formation and development of a tribologically transformed structure in subsurface and plowing effect by fretting in surface.
文摘A numerical study of partial slip boundary condition is investigated. The stagnation-point flow problem involving some physio-chemical parameters has been elucidated. The process involves developing a multivariate mathematical model for the flow and transforming it into a coupled univariate equation. Key parameters of interest in the study are the buoyancy force, the surface stretching, the unsteadiness, the radiation, the dissipation effects, the slip effects, the species reaction and the magnetic field parameters. It is concluded that the impact of physio-chemical factors significantly alters the kinematics of the flow in order to optimally achieve desired product characteristics.
文摘This paper is an analytical study of the rotating flow of a third grade fluid past a porous plate with partial slip effects. It serves as a flow model for the study of polymers. The analytic solution has been determined using homotopy analysis method （HAM）.
基金supported by the National Natural Science Foundation of China(Grant Nos.12262033,12272269,12062021,and 12062022)the Ningxia Hui Autonomous Region Science and Technology Innovation Leading Talent Training Project of China(Grant Nos.2020GKLRLX01 and 2022GKLRLX04)+1 种基金the Natural Science Foundation of Ningxia(Grant No.2023AAC02003)the Shanghai Pilot Program for Basic Research,and Shanghai Gaofeng Project for University Academic Program Development.
文摘The study investigates the partial slip contact problem between thermoelectric material and periodic punches including flat and cylindrical punches under various loading conditions,including normal force,energy flux,and electric current density.When developing and enhancing thermoelectric devices intended for energy harvesting and temperature regulation,the relationship between punch geometry and thermoelectric material plays a crucial role.The periodic contact problem leads to the formation of a singular integral equation with a Hilbert kernel,distinguishing it from the traditional Cauchy kernel.It delves into the impact of the thermo-electric-mechanical coupling effect on the evolution of stick-slip zone length and contact stress during partial slip.By formulating the current nonlinear problem into a set of singular integral equations,the study identifies primary variables,including normal and tangential contact stresses,as well as slip and stick zones.The partial contact problem is further simplified by applying the Goodman approximation,enabling an iterative approach to determine the stick-slip zone,contact zone size,and stress distribution.Notably,the research reveals that factors such as the shape of the punch,the coefficient of friction,and TE parameters significantly influence stress strength and the characteristics of the stick-slip zone.
基金supported by the Universiti Kebangsaan Malaysia(UKM)research grant GP-2021-K006388.
文摘In thermofluid systems,the lid-driven square chamber plays an imperative role in analyzing thermodynamics’first and second laws in limited volume cases executed by sheer effects with a prominent role in many industrial applications including electronic cooling,heat exchangers,microfluidic components,solar collectors,and renewable energies.Furthermore,nanofluids as working fluids have demonstrated potential for heat transfer enhancement systems,however there are some concerns about irreversibility problems in the systems.Due to this problem and in line with the applications of partial slip on fluid flow modification and irreversibilities,the present study considers laminar mixed convection and entropy generation analysis of aluminum oxide nanofluid inside a lid-driven wavy cavity having an internal conductive solid body in the presence of a partial slip on the upper surface,which to the best of our knowledge,has not been investigated so far.The fundamental equations of the current work with the appropriate boundary conditions are first made dimensionless and then solved numerically using the Galerkin weighted residual FEM.The main parameters of the flow and heat transfer,entropy generation,and Bejan number are presented and explained in details.The outcomes indicate that the partial slip is more effective when friction irreversibilities govern the cavity.In the presence of slip condition,the flow circulation changes the trend in the middle of the cavity around the solid block leading to a decrease in the isentropic lines at the dense sections with almost 30%less than the case of no-slip condition.It is concluded that partial slip shows different trends on the local Nusselt number interface along the wavy wall improving the average Nusselt number where high friction irreversibilities dominate.
文摘The flow and heat transfer of an electrically conducting non-Newtonian second grade fluid due to a radially stretching surface with partial slip is considered. The partial slip is controlled by a dimensionless slip factor, which varies between zero （total adhesion） and infinity （full slip）. Suitable similarity transformations are used to reduce the resulting highly nonlinear partial differential equations into ordinary differential equations. The issue of paucity of boundary conditions is addressed and an effective numerical scheme is adopted to solve the obtained differential equations even without augmenting any extra boundary conditions. The important findings in this communication are the combined effects of the partial slip, magnetic interaction parameter and the second grade fluid parameter on the velocity and temperature fields. It is interesting to find that the slip increases the momentum and thermal boundary layer thickness. As the slip increases in magnitude, permitting more fluid to slip past the sheet, the skin friction coefficient decreases in magnitude and approaches zero for higher values of the slip parameter, i.e., the fluid behaves as though it were inviscid. The presence of a magnetic field has also substantial effects on velocity and temperature fields.
文摘This investigation deals with the effects of slip, magnetic field, and non- Newtonian flow parameters on the flow and heat transfer of an incompressible, electrically conducting fourth-grade fluid past an infinite porous plate. The heat transfer analysis is carried out for two heating processes. The system of highly non-linear differential equations is solved by the shooting method with the fourth-order Runge-Kutta method for moderate values of the parameters. The effective Broyden technique is adopted in order to improve the initial guesses and to satisfy the boundary conditions at infinity. An exceptional cross-over is obtained in the velocity profile in the presence of slip. The fourth-grade fluid parameter is found to increase the momentum boundary layer thickness, whereas the slip parameter substantially decreases it. Similarly, the non-Newtonian fluid parameters and the slip have opposite effects on the thermal boundary layer thickness.
文摘In this paper, we examine the unsteady magneto hydrodynamic (MHD) flow generated by a disc that is making non-coaxial rotations with a third grade fluid at infinity and moving with a variable acceleration. The fluid is assumed to satisfy slip boundary condition on the disc. The governing equations are three dimensional and highly non-linear in nature. The assumed slip boundary condition is non-linear as well. The governing equations are transformed to a nonlinear boundary value problem which is solved numerically. Comparison of this generalized problem with uniformly accelerated disk satisfying no slip condition is made. Variations of the characterizing dimensionless parameters such as slip parameter λ, acceleration parameter c, unsteady parameter τ, third grade parameter β, suction parameter S, and magnetic parameter N on the flow field are discussed and analyzed graphically.
基金Project supported by the Science and Technology Development Project of Jilin Province (No. 20020631)
文摘The strain difference of steel and concrete under vertical concentrated load was analyzed on the basis of elastic theory, and was compared with ideal solution of steel and concrete under vertical uniform load. The results indicate that the computing formula concluded from the paper is believable. The practical structure usually bears concentrated load, so it can be used in the practical engineering.
基金National Natural Science Foundation of China (40574022)the Central Public Affair Program Award for the Specific Academic Research (ZDJ2007-1)One-Hundred Individual Program of Chinese Academy of Sciences (99T3004WAZ)
文摘With co-seismic surface rupture slip displacements provided by the field observation for the 2001 MS8.1 West Kunlun Mountain Pass earthquake, this paper estimates the rupture speed on the main faulting segment with a long straight fault trace on the surface based on a simple slip-weakening rupture model, in which the frictional overshoot or undershoot are involved in consideration of energy partition during the earthquake faulting. In contrast to the study of Bouchon and Vallée, in which the rupture propagation along the main fault could exceed the local shear-wave speed, perhaps reach the P-wave speed on a certain section of fault, our results show that, under a slip-weakening assumption combined with a frictional undershoot (partial stress drop model), average rupture speed should be equal to or less than the Rayleigh wave speed with a high seismic radiation efficiency, which is consistent with the result derived by waveform inversion and the result estimated from source stress field. Associated with the surface rupture mechanism, such as partial stress drop (frictional undershoot) associated with the apparent stress, an alternative rupture mechanism based on the slip-weakening model has also been discussed.
