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1 – 10 of 605
Article
Publication date: 12 December 2018

Yu Bai, Bo Xie, Yan Zhang, Yingjian Cao and Yunpeng Shen

The purpose of this paper is to investigate the two-dimensional stagnation-point flow, heat and mass transfer of an incompressible upper-convected Oldroyd-B MHD nanofluid…

Abstract

Purpose

The purpose of this paper is to investigate the two-dimensional stagnation-point flow, heat and mass transfer of an incompressible upper-convected Oldroyd-B MHD nanofluid over a stretching surface with convective heat transfer boundary condition in the presence of thermal radiation, Brownian motion, thermophoresis and chemical reaction. The process of heat and mass transfer based on Cattaneo–Christov double-diffusion model is studied, which can characterize the features of thermal and concentration relaxations factors.

Design/methodology/approach

The governing equations are developed and similarly transformed into a set of ordinary differential equations, which are solved by a newly approximate analytical method combining the double-parameter transformation expansion method with the base function method (DPTEM-BF).

Findings

An interesting phenomenon can be found that all the velocity profiles first enhance up to a maximal value and then gradually drop to the value of the stagnation parameter, which indicates the viscoelastic memory characteristic of Oldroyd-B fluid. Moreover, it is revealed that the thickness of the thermal and mass boundary layer is increasing with larger values of thermal and concentration relaxation parameters, which indicates that Cattaneo–Christov double-diffusion model restricts the heat and mass transfer comparing with classical Fourier’s law and Fick’s law.

Originality/value

This paper focuses on stagnation-point flow, heat and mass transfer combining the constitutive relation of upper-convected Oldroyd-B fluid and Cattaneo–Christov double diffusion model.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 23 September 2020

H. Waqas, M. Imran, Taseer Muhammad, Sadiq M. Sait and R. Ellahi

The purpose of this study is to discuss the Darcy–Forchheimer nanoliquid bio-convection flow by stretching cylinder/plate with modified heat and mass fluxes, activation…

Abstract

Purpose

The purpose of this study is to discuss the Darcy–Forchheimer nanoliquid bio-convection flow by stretching cylinder/plate with modified heat and mass fluxes, activation energy and gyrotactic motile microorganism features.

Design/methodology/approach

The proposed flow model is based on flow rate, temperature of nanomaterials, volume fraction of nanoparticles and gyrotactic motile microorganisms. Heat and mass transport of nanoliquid is captured by the usage of popular Buongiorno relation, which allows us to evaluate novel characteristics of thermophoresis diffusion and Brownian movement. Additionally, Wu’s slip (second-order slip) mechanisms with double stratification are incorporated. For numerical and graphical results, the built-in bvp4c technique in computational software MATLAB along with shooting technique is used.

Findings

The influence of key elements is illustrated pictorially. Velocity decays for higher magnitude of first- and second-order velocity slips and bioconvection Rayleigh number. The velocity of fluid has an inverse relation with mixed convection parameter and local inertia coefficient. Temperature field enhances with the increase in estimation of thermal stratification Biot number and radiation parameter. A similar situation for concentration field is observed for mixed convection parameter and concentration relaxation parameter. Microorganism concentration profile decreases for higher values of bioconvection Lewis number and Peclet number. A detail discussion is given to see how the graphical aspects justify the physical ones.

Originality/value

To the best of the authors’ knowledge, original research work is not yet available in existing literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 3 January 2017

Junaid Ahmad Khan, M. Mustafa, T. Hayat, Mustafa Turkyilmazoglu and A. Alsaedi

The purpose of the present study is to explore a three-dimensional rotating flow of water-based nanofluids caused by an infinite rotating disk.

Abstract

Purpose

The purpose of the present study is to explore a three-dimensional rotating flow of water-based nanofluids caused by an infinite rotating disk.

Design/methodology/approach

Mathematical formulation is performed using the well-known Buongiorno model which accounts for the combined influence of Brownian motion and thermophoresis. The recently suggested condition of passively controlled wall nanoparticle volume fraction has been adopted.

Findings

The results reveal that temperature decreases with an increase in thermophoresis parameter, whereas it is negligibly affected with a variation in the Brownian motion parameter. Axial velocity is negative because of the downward flow in the vertical direction.

Originality/value

Two- and three-dimensional streamlines are also sketched and discussed. The computations are found to be in very good agreement with the those of existing studies in the literature for pure fluid.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 29 December 2017

O.K. Koriko, I.L. Animasaun, M. Gnaneswara Reddy and N. Sandeep

The purpose of this paper is to scrutinize the effects of nonlinear thermal radiation and thermal stratification effects on the flow of three-dimensional Eyring-Powell…

92

Abstract

Purpose

The purpose of this paper is to scrutinize the effects of nonlinear thermal radiation and thermal stratification effects on the flow of three-dimensional Eyring-Powell 36 nm alumina-water nanofluid within the thin boundary layer in the presence of quartic autocatalytic kind of chemical reaction effects, and to unravel the effects of a magnetic field parameter, random motion of the tiny nanoparticles and volume fraction on the flow.

Design/methodology/approach

The chemical reaction between homogeneous (Eyring-Powell 36 nm alumina-water) bulk fluid and heterogeneous (three molecules of the catalyst at the surface) in the flow of magnetohydrodynamic three-dimensional flow is modeled as a quartic autocatalytic kind of chemical reaction. The electromagnetic radiation which occurs within the boundary layer is treated as the nonlinear form due to the fact that Taylor series expansion may not give full details of such effects within the boundary layer. With the aid of appropriate similarity variables, the nonlinear coupled system of partial differential equation which models the flow was reduced to ordinary differential equation boundary value problem.

Findings

A favorable agreement of the present results is obtained by comparing it for a limiting case with the published results; hence, reliable results are presented. The concentration of homogeneous bulk fluid (Eyring-Powell nanofluid) increases and decreases with ϕ and Pr, respectively. The increase in the value of magnetic field parameter causes vertical and horizontal velocities of the flow within the boundary layer to decrease significantly. The decrease in the vertical and horizontal velocities of Eyring-Powell nanofluid flow within the boundary layer is guaranteed due to an increase in the value of M. Concentration of homogeneous fluid increases, while the concentration of the heterogeneous catalyst at the wall decreases with M.

Originality/value

Considering the industrial applications of thermal stratification in solar engineering and polymer processing where the behavior of the flow possesses attributes of Eyring-Powell 36 nm alumina-water, this paper presents the solution of the flow problem considering 36 nm alumina nanoparticles, thermophoresis, stratification of thermal energy, Brownian motion and nonlinear thermal radiation. In addition, the aim and objectives of this paper fill such vacuum in the industry.

Details

Multidiscipline Modeling in Materials and Structures, vol. 14 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 3 December 2018

Aurang Zaib, Rizwan Ul Haq, A.J. Chamkha and M.M. Rashidi

The study aims to numerically examine the impact of nanoparticles on an unsteady flow of a Williamson fluid past a permeable convectively heated shrinking sheet.

Abstract

Purpose

The study aims to numerically examine the impact of nanoparticles on an unsteady flow of a Williamson fluid past a permeable convectively heated shrinking sheet.

Design/methodology/approach

In sort of the solution of the governing differential equations, suitable transformation variables are used to get the system of ODEs. The converted equations are then numerically solved via the shooting technique.

Findings

The impacts of such parameters on the velocity profile, temperature distribution and the concentration of nanoparticles are examined through graphs and tables. The results point out that multiple solutions are achieved for certain values of the suction parameter and for decelerating flow, while for accelerating flow, the solution is unique. Further, the non-Newtonian parameter reduces the fluid velocity and boosts the temperature distribution and concentration of nanoparticles in the first solution, while the reverse drift is noticed in the second solution.

Practical implications

The current results may be used in many applications such as biomedicine, industrial, electronics and solar energy.

Originality/value

The authors think that the current results are new and significant, which are used in many applications such as biomedicine, industrial, electronics and solar energy. The results have not been considered elsewhere.

Details

World Journal of Engineering, vol. 15 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 10 July 2019

Muhammad Ijaz Khan, M.Z. Kiyani, Tasawar Hayat, Muhammad Faisal Javed and I. Ahmad

This paper aims to address double-stratified stagnation-point flow of Williamson nanomaterial with entropy generation. Flow through porous medium is discussed. Energy…

Abstract

Purpose

This paper aims to address double-stratified stagnation-point flow of Williamson nanomaterial with entropy generation. Flow through porous medium is discussed. Energy equation is modeled in existence of viscous dissipation, Brownian motion and thermophoresis. Furthermore, convective boundary conditions are considered. Total entropy rate is presented.

Design/methodology/approach

The non-linear flow expressions are converted to ordinary ones by implementation of suitable transformations. The obtained ordinary system is tackled for series solutions via homotopy analysis method.

Findings

Till date no one has considered the irreversibility analysis in stagnation-point flow of Williamson nanomaterial with double stratification, porous medium and convective conditions. The basic objective of present research is to investigate the convective stagnation point flow of Williamson liquid with entropy concept and porous medium.

Originality/value

As per the authors’ knowledge, no such work is yet present in the literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 6 August 2019

Muhammad Waqas, Muhammad Mudassar Gulzar, Zeeshan Asghar, Z. Ali, Waqar Azeem Khan and Abdul Sattar Dogonchi

The purpose of this study is to elaborate mixed convection impact in stratified nanofluid flow by convectively heated moving surface. Rheological relations of second-grade…

Abstract

Purpose

The purpose of this study is to elaborate mixed convection impact in stratified nanofluid flow by convectively heated moving surface. Rheological relations of second-grade fluid are used for formulation. Magnetic field, heat absorption/generation and convective conditions are considered for modeling.

Design/methodology/approach

Convergent solutions are achieved using homotopy procedure.

Findings

The authors found opposing behavior for radiation and thermal stratification variables against thermal field.

Originality/value

No such analysis has yet been reported.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 24 September 2019

Mangwiro Magodora, Hiranmoy Mondal and Precious Sibanda

The purpose of this paper is to focus on the application of Chebyshev spectral collocation methodology with Gauss Lobatto grid points to micropolar fluid over a stretching…

Abstract

Purpose

The purpose of this paper is to focus on the application of Chebyshev spectral collocation methodology with Gauss Lobatto grid points to micropolar fluid over a stretching or shrinking surface. Radiation, thermophoresis and nanoparticle Brownian motion are considered. The results have attainable scientific and technological applications in systems involving stretchable materials.

Design/methodology/approach

The model equations governing the flow are transformed into non-linear ordinary differential equations which are then reworked into linear form using the Newton-based quasilinearization method (SQLM). Spectral collocation is then used to solve the resulting linearised system of equations.

Findings

The validity of the model is established using error analysis. The velocity, temperature, micro-rotation, skin friction and couple stress parameters are conferred diagrammatically and analysed in detail.

Originality/value

The study obtains numerical explanations for rapidly convergent solutions using the spectral quasilinearization method. Convergence of the numerical solutions was monitored using the residual error analysis. The influence of radiation, heat and mass parameters on the flow are depicted graphically and analysed. The study is an extension on the work by Zheng et al. (2012) and therefore the novelty is that the authors tend to take into account nanoparticles, Brownian motion and thermophoresis in the flow of a micropolar fluid.

Details

Multidiscipline Modeling in Materials and Structures, vol. 16 no. 2
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 10 April 2009

Hongli Liu, Changxi Li and Li Li

The purpose of this paper is to establish mass balance model and predict the concentration and diameter distribution of indoor suspended particulate matters (SPM).

223

Abstract

Purpose

The purpose of this paper is to establish mass balance model and predict the concentration and diameter distribution of indoor suspended particulate matters (SPM).

Design/methodology/approach

Taking the small offices and residences for a research objective, this paper analyzes the major factors to affect the concentration and diameter distribution of indoor SPM, founds the deposition ratio model, the penetration factor model and the mass balance model to predict the concentration and diameter distribution of indoor SPM. According to the real‐time measuring data, the feature of building defence structure and the concentration and diameter distribution of outdoor SPM, the deposition model, the penetration model and indoor air capacity are used as input parameter of the mass balance model.

Findings

The size of defence in natural ventilation, the pressure difference of both sides and the friction velocity have less influence on the concentration and diameter distribution of indoor SPM, but the concentration and diameter distribution of outdoor SPM mainly affects that of indoor SPM. Indoor particle concentration change with outdoor particle concentration, and less than later because of indoor particle deposition. The prediction results are basically in agreement with the measuring data.

Research limitations/implications

Real‐time and accuracy of measuring data of outdoor SPM are the main limitations which the prediction model are simulated.

Practical implications

The prediction results can provide scientific theory basis for making environmental standards of particulate matter and the control of indoor air quality.

Originality/value

A new method to predict the concentration and diameter distribution of indoor SPM.

Details

Kybernetes, vol. 38 no. 3/4
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 9 August 2021

Jawad Raza, Sumera Dero, Liaquat Ali Lund and Zurni Omar

The purpose of study is to examine the dual nature of the branches for the problem of Darcy–Forchheimer porous medium flow of rotating nanofluid on a linearly…

Abstract

Purpose

The purpose of study is to examine the dual nature of the branches for the problem of Darcy–Forchheimer porous medium flow of rotating nanofluid on a linearly stretching/shrinking surface under the field of magnetic influence. The dual nature of the branches confronts the uniqueness and existence theorem, moreover, mathematically it is a great achievement. For engineering purposes, this study applied a linear stability test on the multiple branches to determine which solution is physically reliable (stable).

Design/methodology/approach

Nanofluid model has been developed with the help of Buongiorno model. The partial differential equations in space coordinates for the law of conservation of mass, momentum and energy have been transformed into ordinary differential equations by introducing the similarity variables. Two numerical techniques, namely, the shooting method in Maple software and the three-stage Lobatto IIIA method in Matlab software, have been used to find multiple branches and to accomplish stability analysis, respectively.

Findings

The parametric investigation has been executed to find the multiple branches and explore the effects on skin friction, Sherwood number, Nusselt number, concentration and temperature profiles. The findings exhibited the presence of dual branches only in the case of a shrinking sheet.

Originality/value

The originality of work is a determination of multiple branches and the performance of the stability analysis of the branches. It has also been confirmed that such a study has not yet been considered in the previous literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 32 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

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