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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 energy and…

179

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

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Article
Publication date: 18 August 2021

Manoj Kumar Nayak, Sachin Shaw, H. Waqas and Taseer Muhammad

The purpose of this study is to investigate the Cattaneo-Christov double diffusion, multiple slips and Darcy-Forchheimer’s effects on entropy optimized and thermally radiative…

102

Abstract

Purpose

The purpose of this study is to investigate the Cattaneo-Christov double diffusion, multiple slips and Darcy-Forchheimer’s effects on entropy optimized and thermally radiative flow, thermal and mass transport of hybrid nanoliquids past stretched cylinder subject to viscous dissipation and Arrhenius activation energy.

Design/methodology/approach

The presented flow problem consists of the flow, heat and mass transportation of hybrid nanofluids. This model is featured with Casson fluid model and Darcy-Forchheimer model. Heat and mass transportations are represented with Cattaneo-Christov double diffusion and viscous dissipation models. Multiple slip (velocity, thermal and solutal) mechanisms are adopted. Arrhenius activation energy is considered. For graphical and numerical data, the bvp4c scheme in MATLAB computational tool along with the shooting method is used.

Findings

Amplifying curvature parameter upgrades the fluid velocity while that of porosity parameter and velocity slip parameter whittles down it. Growing mixed convection parameter, curvature parameter, Forchheimer number, thermally stratified parameter intensifies fluid temperature. The rise in curvature parameter and porosity parameter enhances the solutal field distribution. Surface viscous drag gets controlled with the rising of the Casson parameter which justifies the consideration of the Casson model. Entropy generation number and Bejan number upgrades due to growth in diffusion parameter while that enfeeble with a hike in temperature difference parameter.

Originality/value

To the best of the authors’ knowledge, this research study is yet to be available in the existing literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 32 no. 6
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 6 August 2020

Iqra Shahzadi and Nabeela Kausar

The formulation of nonlinear convective non-Newtonian material is reported in this communication. Aspects of thermal radiation and heat source are taken into account for heat…

71

Abstract

Purpose

The formulation of nonlinear convective non-Newtonian material is reported in this communication. Aspects of thermal radiation and heat source are taken into account for heat transport analysis. The novel stratifications (thermal and solutal) and convective conditions are considered simultaneously. The boundary-layer concept is implemented to simplify the complex mathematical expressions.

Design/methodology/approach

The well-known optimal homotopy scheme develops the computations. Optimal values regarding nonzero auxiliary variables are calculated and examined.

Findings

Nonlinear convective flow; Thixotropic non-Newtonian material; Thermal radiation; Heat source; Stratifications and convective conditions; Buongiorno model.

Originality/value

To the best of authors’ knowledge, no such analysis has yet been reported.

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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 fluid…

75

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

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Article
Publication date: 7 January 2025

Ali Raza, Umair Khan, Aurang Zaib, Anuar Ishak and Syed Modassir Hussain

This article identifies hybrid nanofluids and industrial thermal engineering devices as significant sources of solar energy. In this study, various nanoparticles suspended in base…

18

Abstract

Purpose

This article identifies hybrid nanofluids and industrial thermal engineering devices as significant sources of solar energy. In this study, various nanoparticles suspended in base fluids such as water (H2O) and carboxymethyl cellulose (CMC), along with nanoparticles like graphene oxide (GO) and molybdenum disulfide (MoS2), are examined. The model also incorporates permeability and the effects of angled magnetic fields to provide a comprehensive analysis.

Design/methodology/approach

We have utilized the fractal fractional operator definition, the quickest and most advanced fractional approach, to address the problems with the hybrid nanofluid suspension. The integral transform scheme, i.e. the Laplace transform, converts the governing equations into a fractional form before various numerical methods are applied to solve the problem. Further, some numerical schemes to address the Laplace inverse are also utilized.

Findings

The fractional effects on flow rate and heat transfer are evident at varying time intervals. Consequently, we conclude that as the fractal constraints increase, the momentum and heat profiles decelerate. Furthermore, all necessary conditions are satisfied, resulting in the momentum and temperature fields decreasing near the plate and increasing over time. Additionally, the water-based (H2O + Go + MoS2) solution exhibits a more pronounced impact compared to the CMC-based (CMC + Go + MoS2) hybrid suspension.

Practical implications

The findings could be very useful in enhancing the efficiency of thermal systems. These findings align more accurately with conventional solutions and can be used to build and optimize various heat management strategies.

Originality/value

The primary goals of this research are to examine the thermal and flow properties of hybrid nanofluids for manufacturing purposes of thermal engineering equipment utilizing fractal fractional definition. Further, to improve thermal system productivity by applying sophisticated fractional techniques to better and maximize heat and momentum transmission in these hybrid nanofluid solutions

Details

Multidiscipline Modeling in Materials and Structures, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 28 June 2019

Muhammad Waqas, M. Mudassar Gulzar, Waqar Azeem Khan, Muhammad Ijaz Khan and Niaz B. Khan

This paper aims to elaborate the characteristics of magneto-Maxwell nanoliquid toward moving radiated surface. Flow analysis subject to Darcy–Forchheimer concept is studied…

61

Abstract

Purpose

This paper aims to elaborate the characteristics of magneto-Maxwell nanoliquid toward moving radiated surface. Flow analysis subject to Darcy–Forchheimer concept is studied. Newtonian heat/mass conditions and heat source aspects are taken into account for modeling. Apposite transformations are introduced for non-dimensionalization process.

Design/methodology/approach

Optimal homotopy analysis method is implemented to compute convergent solutions of nonlinear ordinary differential equations.

Findings

Temperature field increments when thermophoresis, heat generation and Brownian movement parameters are increased, whereas reverse situation is noticed for larger Prandtl number. The results also witness that concentration distribution has opposite characteristics for larger thermophoresis and Brownian movement parameters. Furthermore, the presented analysis reduces to traditional Darcy relation in the absence of local inertia coefficient.

Originality/value

As per the authors’ knowledge, no such analysis has been yet reported.

Details

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

Keywords

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Article
Publication date: 23 October 2020

Muhammad Waqas, Ubaid Ahmed Nisar, Muhammad Ijaz Khan and Sabir Ali Shehzad

The purpose of this paper is to address the impact of gravity induced stretching flow of second grade liquid subject to thermal radiation. The flow is generated by the stretching…

70

Abstract

Purpose

The purpose of this paper is to address the impact of gravity induced stretching flow of second grade liquid subject to thermal radiation. The flow is generated by the stretching of an impermeable cylinder. Stagnation point flow is considered. Convective type boundary conditions are applied on temperature and concentration. The present investigation further includes the aspects of magnetohydrodynamics, Joule heating, chemical reaction and viscous dissipation and heat generation/absorption.

Design/methodology/approach

The ordinary differential expressions are formed using suitable similarity transformations from the governing partial differential expressions. The subsequent nonlinear ordinary differential expressions are solved analytically using homotopy concept to report the consequences of different dimensionless physical parameters in graphical and tabular forms.

Findings

The results witnessed that increasing values of curvature parameter corresponds to higher temperature and concentration. Besides this, the impacts of destructive and constructive chemical processes on the concentration distribution are noted opposite.

Originality/

No such analysis has yet been reported.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 4
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 27 August 2019

A.S. Dogonchi, Muhammad Waqas, S.R. Afshar, Seyyed Masoud Seyyedi, M. Hashemi-Tilehnoee, Ali J. Chamkha and D.D. Ganji

This paper aims to study the impacts of viscous dissipation, thermal radiation and Joule heating on squeezing flow current and the heat transfer mechanism for a…

202

Abstract

Purpose

This paper aims to study the impacts of viscous dissipation, thermal radiation and Joule heating on squeezing flow current and the heat transfer mechanism for a magnetohydrodynamic (MHD) nanofluid flow in parallel disks during a suction/blowing process.

Design/methodology/approach

First, the governing momentum/energy equations are transformed into a non-dimensional form and then the obtained equations are solved by modified Adomian decomposition method (ADM), known as Duan–Rach approach (DRA).

Findings

The effect of the radiation parameter, suction/blowing parameter, magnetic parameter, squeezing number and nanoparticles concentration on the heat transfer and flow field are investigated in the results. The results show that the fluid velocity increases with increasing suction parameter, while the temperature profile decreases with increasing suction parameter.

Originality/value

A complete analysis of the MHD fluid squeezed between two parallel disks by considering Joule heating, thermal radiation and adding different nanoparticles using the novel method called DRA is addressed.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 2
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 6 August 2019

Tasawar Hayat, Ikram Ullah, Muhammad Waqas and Ahmed Alsaedi

The purpose of this study is to study the impacts of exponential space-dependent heat source (ESHS) and thermal radiation in Marangoni convective flow of Cross fluid. The…

97

Abstract

Purpose

The purpose of this study is to study the impacts of exponential space-dependent heat source (ESHS) and thermal radiation in Marangoni convective flow of Cross fluid. The passively controlled model is developed to exhibit the nanoparticles’ concentration on the surface.

Design/methodology/approach

The resulting problem under consideration is tackled by using the shooting approach.

Findings

Temperature field augments with enhancement of the thermophoretic, exponential-based space heat source (ESHS) and radiation parameters, whereas it decays with the increase of the Marangoni ratio parameter.

Originality/value

To the best of the authors’ knowledge, 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

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Article
Publication date: 4 February 2025

Muhammad Waqas, Abdul Haseeb Tahir, Hussain Tariq and Ayesha Rashid Khan

We investigate how green transformational leadership (GTL) influences green innovative service behavior (GISB), particularly in the hospitality sector, which faces significant…

38

Abstract

Purpose

We investigate how green transformational leadership (GTL) influences green innovative service behavior (GISB), particularly in the hospitality sector, which faces significant environmental challenges. Drawing from social identity theory (SIT), we introduce green organizational identity (GOI) as a mediating mechanism through which GTL fosters GISB. Furthermore, we propose a moderated mediation model whereby a green knowledge-sharing climate (GKSC) serves as a first-stage moderator to further understand how and when GTL fosters GISB through GOI.

Design/methodology/approach

We employed a multi-study design (i.e. two independent studies across China) to test the hypothesized relationships. Study 1 involved full-time employees from the service industry in China, including healthcare, telecommunication, and insurance sectors (N = 313). Study 2 employed a time-lagged dyadic design, collecting responses from employees and their managers at three different time points in the hospitality sector (N = 419).

Findings

In Study 1, the simple mediation results demonstrate that GTL positively influences GISB through the mediating role of GOI. Moreover, in Study 2, the moderating effect of GKSC was supported, showing that in organizations with strong green knowledge-sharing climate, the indirect effect of GTL on GISB via GOI is amplified.

Originality/value

In our work, we address a critical gap in the literature by identifying both the mechanisms and contextual factors that explain how GTL influences GISB. By introducing GOI as a mediator and GKSC as a first-stage moderator, the study advances understanding of how leadership, organizational identity, and a green-supportive climate interact to promote eco-friendly innovation in service organizations. This contributes both theoretically and practically to the development of effective strategies for advancing green initiatives in the service sector.

Details

Journal of Service Theory and Practice, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2055-6225

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