M. Mustafaa, T. Hayat and S. Obaidat
This paper aims to discuss the flow and heat transfer characteristics over an exponentially stretching sheet in a nanofluid with convective boundary conditions. The effects of…
Abstract
Purpose
This paper aims to discuss the flow and heat transfer characteristics over an exponentially stretching sheet in a nanofluid with convective boundary conditions. The effects of Brownian motion and thermophoresis are also accounted.
Design/methodology/approach
The flow is therefore governed by the Brownian motion parameter (Nb), the thermophoresis parameter (Nt), the Prandtl number (Pr), the Lewis number (Le) and the Biot number (Bi). The analytic solutions of the arising differential systems have been obtained by homotopy analysis method (HAM).
Findings
The temperature rises and the thermal boundary layer thickens with an increase in the Brownian motion and thermophoresis parameters. The surface heat and mass transfer appreciably increase with an increase in the Prandtl and Lewis numbers.
Originality/value
The presented results also include the analysis for constant wall temperature.
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Sivasankaran Sivanandam, Turki J. Alqurashi and Hashim M. Alshehri
This study aims to investigate numerically the impact of the three-dimensional convective nanoliquid flow on a rotating frame embedded in the non-Darcy porous medium in the…
Abstract
Purpose
This study aims to investigate numerically the impact of the three-dimensional convective nanoliquid flow on a rotating frame embedded in the non-Darcy porous medium in the presence of activation energy. The cross-diffusion effects, i.e. Soret and Dufour effects, and heat generation are included in the study. The convective heating condition is applied on the bounding surface.
Design/methodology/approach
The control model consisted of a system of partial differential equations (PDE) with boundary constraints. Using suitable similarity transformation, the PDE transformed into an ordinary differential equation and solved numerically by the Runge–Kutta–Fehlberg method. The obtained results of velocity, temperature and solute concentration characteristics plotted to show the impact of the pertinent parameters. The heat and mass transfer rate and skin friction are also calculated.
Findings
It is found that both Biot numbers enhance the heat and mass distribution inside the boundary layer region. The temperature increases by increasing the Dufour number, while concentration decreases by increasing the Dufour number. The heat transfer is increased up to 8.1% in the presence of activation energy parameter (E). But, mass transfer rate declines up to 16.6% in the presence of E.
Practical implications
The applications of combined Dufour and Soret effects are in separation of isotopes in mixture of gases, oil reservoirs and binary alloys solidification. The nanofluid with porous medium can be used in chemical engineering, heat exchangers and nuclear reactor.
Social implications
This study is mainly useful for thermal sciences and chemical engineering.
Originality/value
The uniqueness in this research is the study of the impact of activation energy and cross-diffusion on rotating nanoliquid flow with heat generation and convective heating condition. The obtained results are unique and valuable, and it can be used in various fields of science and technology.
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M. Sheikholeslami and D.D. Ganji
Nanofluid flow which is squeezed between parallel plates is studied using differential transformation method (DTM). The fluid in the enclosure is water containing different types…
Abstract
Purpose
Nanofluid flow which is squeezed between parallel plates is studied using differential transformation method (DTM). The fluid in the enclosure is water containing different types of nanoparticles: Al2O3 and CuO. The effective thermal conductivity and viscosity of nanofluid are calculated by Koo–Kleinstreuer–Li (KKL) correlation. The comparison between the results from DTM and numerical method are in well agreement which proofs the capability of this method for solving such problems. Effects of the squeeze number and nanofluid volume fraction on flow and heat transfer are examined. Results indicate that Nusselt number augment with increase of the nanoparticle volume fraction. Also, it can be found that heat transfer enhancement of CuO is higher than Al2O3.
Design/methodology/approach
The problem of nanofluid flow which is squeezed between parallel plates is investigated analytically using DTM. The fluid in the enclosure is water containing different types of nanoparticles: Al2O3 and CuO. The effective thermal conductivity and viscosity of nanofluid are calculated by KKL correlation. In this model, effect of Brownian motion on the effective thermal conductivity is considered. The comparison between the results from DTM and numerical method are in well agreement which proves the capability of this method for solving such problems. The effect of the squeeze number and the nanofluid volume fraction on flow and heat transfer is investigated. The results show that Nusselt number increase with increase of the nanoparticle volume fraction. Also, it can be found that heat transfer enhancement of CuO is higher than Al2O3.
Findings
The effect of the squeeze number and the nanofluid volume fraction on flow and heat transfer is investigated. The results show that Nusselt number increase with increase of the nanoparticle volume fraction. Also, it can be found that heat transfer enhancement of CuO is higher than Al2O3.
Originality/value
This paper is original.
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Ruhaila Md Kasmani, S. Sivasankaran, M. Bhuvaneswari and Ahmed Kadhim Hussein
The purpose of this study is to investigate the Soret and Dufour effects on the double-diffusive convective boundary layer flow of a nanofluid past a moving wedge in the presence…
Abstract
Purpose
The purpose of this study is to investigate the Soret and Dufour effects on the double-diffusive convective boundary layer flow of a nanofluid past a moving wedge in the presence of suction.
Design/methodology/approach
The similarity transformation is applied to convert the governing nonlinear partial differential equations into ordinary differential equations. Then, they are solved numerically by the fourth-order Runge–Kutta–Gill method along with the shooting technique and the Newton–Raphson method. In addition, the ordinary differential equations are also analytically solved by the homotopy analysis method.
Findings
The results for dimensionless velocity, temperature, solutal concentration and nanoparticle volume fraction profiles, as well as local skin friction coefficient and local Nusselt and local Sherwood numbers are presented through the plots for various combinations of pertinent parameters involved in the study. The heat transfer rate increases on increasing the Soret parameter and it decreases on increasing the Dufour parameter. The mass transfer behaves oppositely to heat transfer.
Practical implication
In engineering applications, a wedge is used to hold objects in place, such as engine parts in the gate valves. A gate valve is the valve that opens by lifting a wedge-shaped disc to control the timing and quantity of fluid flow into an engine.
Originality/value
No such investigation is available in literature, and therefore, the results obtained are novel.
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The purpose of this paper is to investigate a model for convection induced by the selective absorption of radiation in a fluid layer. The concentration based internal heat source…
Abstract
Purpose
The purpose of this paper is to investigate a model for convection induced by the selective absorption of radiation in a fluid layer. The concentration based internal heat source is modelled quadratically. Both linear instability and global nonlinear energy stability analyses are tested using three dimensional simulations. The results show that the linear threshold accurately predicts on the onset of instability in the basic steady state. However, the required time to arrive at the steady state increases significantly as the Rayleigh number tends to the linear threshold.
Design/methodology/approach
The author introduce the stability analysis of the problem of convection induced by absorption of radiation in fluid layer, then the author select a situations which have very big subcritical region. Then, the author develop a three dimensions simulation for the problem. To do this, first, the author transform the problem to velocity – vorticity formulation, then the author use a second order finite difference schemes. The author use implicit and explicit schemes to enforce the free divergence equation. The size of the Box is evaluated according to the normal modes representation. Moreover, the author adopt the periodic boundary conditions for velocity and temperature in the $x, y$ dimensions.
Findings
This paper explores a model for convection induced by the selective absorption of radiation in a fluid layer. The results demonstrate that the linear instability thresholds accurately predict the onset of instability. A three-dimensional numerical approach is adopted.
Originality/value
As the author believe, this paper is one of the first studies which deal with study of stability of convection using a three dimensional simulation. When the difference between the linear and nonlinear thresholds is very large, the comparison between these thresholds is very interesting and useful.
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Prabhugouda Mallanagouda Patil, Geeta Hadimani, Shashikant A., P.S. Kulkarni and Mukesh Kumar
This paper aims to provide a detailed study on the influence of slip flow and thermal jump over mixed convection flow along an exponentially stretching surface. Also, impacts of…
Abstract
Purpose
This paper aims to provide a detailed study on the influence of slip flow and thermal jump over mixed convection flow along an exponentially stretching surface. Also, impacts of suction/blowing, volumetric heat source/sink and velocity ratio parameter will be studied in this analysis.
Design/methodology/approach
The modeled governing equations for the assumed problem are dimensional nonlinear partial differential equations in nature. To reduce these equations, non-similar transformations are used to get the dimensionless nonlinear partial differential equations. Then, quasi-linearization technique is used to linearize these non-dimensional nonlinear partial differential equations. Finally, an implicit finite difference scheme is used to discretize the resulting equations.
Findings
The physical explanations are provided for the variations of various non-dimensional governing parameters over the velocity and temperature profiles. Also, the effects of these dimensionless parameters on skin friction coefficient and heat transfer rate are scrutinized in a manner which highlights their physical interpretation. The detailed discussion exhibits the fact that the streamwise co-ordinate velocity ratio parameter, partial slip parameter and the thermal jump parameter have significant influence over the flow and thermal fields.
Originality/value
This work has not been reported in the literature to the authors’ best of knowledge.
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Ankita Bisht and Rajesh Sharma
The purpose of this study is to provide a numerical investigation of Casson nanofluid along a vertical nonlinear stretching sheet with variable thermal conductivity and viscosity.
Abstract
Purpose
The purpose of this study is to provide a numerical investigation of Casson nanofluid along a vertical nonlinear stretching sheet with variable thermal conductivity and viscosity.
Design/methodology/approach
The boundary-layer equations are presented in the dimensionless form using proper non-similar transformations. The subsequent non-dimensional nonlinear partial differential equations are solved using the implicit finite difference technique. To linearize the nonlinear terms present in these equations, the quasilinearization technique is used.
Findings
The investigation showed graphically the temperature, velocity and nanoparticle volume fraction for particular included physical parameters. It is observed that the velocity profile decreases with an increase in the values of Casson fluid parameter while increases with an increase in the viscosity variation parameter. The temperature profile enhances for large values of velocity variation parameter and thermal conductivity parameter while it reduces for large values of thermal buoyancy parameter. Further, the Nusselt number and skin-friction coefficient are introduced which are helpful in determining the physical aspects of Casson nanofluid flow.
Practical implications
The immediate control of heat transfer in the industrial system is crucial because of increasing energy prices. Recently, nanotechnology is proposed to control the heat transfer phenomenon. Ongoing research in complex nanofluid has been fruitful in various applications such as solar thermal collectors, nuclear reactors, electronic equipment and diesel–electric conductor. A reasonable amount of nanoparticle when added to the base fluid in solar thermal collectors serves to deeper absorption of incident radiation, and hence it upgrades the efficiency of the solar thermal collectors.
Originality/value
The non-similar solution of Casson nanofluid due to a vertical nonlinear stretching sheet with variable viscosity and thermal conductivity is discussed in this work.
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Yazeed Alfakhri, Mohammad Nurunnabi and Demah Alfakhri
In response to the scarcity of research on Islamic corporate social responsibility (CSR), the purpose of this paper is to explore how young Saudi consumers perceive CSR from an…
Abstract
Purpose
In response to the scarcity of research on Islamic corporate social responsibility (CSR), the purpose of this paper is to explore how young Saudi consumers perceive CSR from an Islamic perspective. The study is focused on Saudi Arabia, a Muslim country, and the largest exporter of petroleum in the world.
Design/methodology/approach
The present study uses a qualitative methodology with 34 in-depth interviews undertaken in two major Saudi cities (Tabouk and Riyadh).
Findings
Utilising social contract theory, this study contributes to the literature by developing an Islamic “CSR Tree” model (which consists of three parts: “roots”, “trunk”, and “crown”) to increase the understanding of Islamic CSR (i-CSR) and consumer behaviour. The roots are hidden, while the trunk and crown are visible. In particular, private social responsibility (the roots of the CSR Tree) incorporating Sadaqa, or values and intention, is the fundamental component on which organisations should base their CSR strategy from an Islamic perspective. The study also reveals that internal, external, and private social responsibilities are connected, and all are dependent on each other. The higher the level of private social responsibility exhibited, the higher the level of external social responsibility.
Originality/value
According to the CSR Tree model presented in this study, an organisation should avoid Riya (showing off) as this would represent shirk or idolatry, which is the opposite of Tawhid. The findings are particularly relevant for advancing the concept of i-CSR and for considering complex perspectives less travelled in the CSR literature. The study suggests that the best strategy for an organisation wishing to pursue an i-CSR agenda would be to balance internal and external responsibilities, and to bear in mind that private responsibility should be the motivation for action, and that CSR should be applied for the benefit of society.
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Ademola Amida, Sameera Algarni and Robert Stupnisky
This study explored graduate students' academic success by testing a hypothesized model based on the self-determination theory (SDT), which posits that motivation, time management…
Abstract
Purpose
This study explored graduate students' academic success by testing a hypothesized model based on the self-determination theory (SDT), which posits that motivation, time management and career aspiration predicts perceived success.
Design/methodology/approach
A quantitative methodology was employed to garner data from a population of 324 graduate students, and then analyzed using structural equation modeling in R.
Findings
Intrinsic motivation was the strongest motivation type that predicted graduate students' perceived success. Time management was another important predictor of perceived success, while career aspiration did not impact students' perception of success. Doctoral students showed significantly higher relatedness when compared to master degree students. In addition, male students showed significantly higher career aspirations than females, while female students showed significantly higher time management than their male counterparts. The results of this study support the SDT as a framework to understand graduate students' academic success.
Originality/value
Implementing the research findings may increase graduate students' academic success. This study suggests direct ways of increasing graduate students' achievement through intrinsic motivation, time management and autonomy, as well as reducing amotivation (lack of motivation) to indirectly enhance academic success.