Comments on “heat transfer in a square porous cavity in presence of square solid block”

2019 ◽  
Vol 30 (2) ◽  
pp. 704-723 ◽  
Author(s):  
D.A.S. Rees
Keyword(s):  
Systematic Approach ◽  
Outer Boundary ◽  
Finite Difference Methods ◽  
Content Type ◽  
Porous Cavity ◽  
Richardson’S Extrapolation ◽  
Steady Solutions ◽  
Internal Block ◽  
Error Testing ◽  
Solid Block

Purpose The purpose of this paper is to discuss the need to attend correctly to the accuracy and the manner in which the value of the streamfunction is determined when two or more impermeable boundaries are present. This is discussed within the context of the paper by Nandalur et al. (2019), which concerns the effect of a centrally located conducting square block on convection in a square sidewall-heated porous cavity. Detailed solutions are also presented which allow the streamfunction to take the natural value on the surface of the internal block. Design/methodology/approach Steady solutions are obtained using finite difference methods. Three different ways in which insulating boundary conditions are implemented are compared. Detailed attention is paid to the iterative convergence of the numerical scheme and to its overall accuracy. Error testing and Richardson’s extrapolation have been used to obtain very precise values of the Nusselt number. Findings The assumption that the streamfunction takes a zero value on the boundaries of both the cavity and the embedded block is shown to be incorrect. Application of the continuity-of-pressure requirement shows that the block and the outer boundary take different constant values. Research limitations/implications The Darcy–Rayleigh number is restricted to values at or below 200; larger values require a finer grid. Originality/value This paper serves as a warning that one cannot assume that the streamfunction will always take a zero value on all impermeable surfaces when two or more are present. A systematic approach to accuracy is described and recommended.

scholarly journals The effect of an embedded solid block on the onset of convection in a porous cavity

2016 ◽  
Vol 26 (3/4) ◽  
pp. 950-976 ◽  
Author(s):  
D. Andrew S. Rees ◽  
Donald A. Nield
Keyword(s):  
Finite Difference Methods ◽  
Heat Conducting ◽  
Onset Of Convection ◽  
Content Type ◽  
Nonlinear Properties ◽  
Bénard Convection ◽  
Benard Convection ◽  
Steady Solutions ◽  
Solid Block ◽  
Detailed Presentation

Purpose – The purpose of this paper is to determine how the presence of an embedded, centrally placed, solid but heat-conducting block affects the onset and development of Darcy-Bénard convection. Design/methodology/approach – Steady solutions are obtained using finite difference methods with SOR as the smoother. A detailed presentation is given of how the interface conditions are modelled, and how a continuity of pressure argument is used to determine the value of the streamfunction on the solid block. Findings – The presence of the block affects strongly both the onset of convection and the nonlinear properties such as the mean Nusselt number and the strength of the fluid circulation. The smallest possible critical Darcy-Rayleigh is found to be 22.0152, which is smaller than 4π2, the value when the block is absent. Research limitations/implications – The Darcy-Rayleigh number is restricted to values at or below 200, which is five times the critical value without a solid block, but the size and conductivity of the block vary between all admissible values. Originality/value – This is the first investigation of the effect of internal obstacles on Darcy-Bénard convection.

Investigation of heat transfer in irregular porous cavity subjected to various boundary conditions

2019 ◽  
Vol 29 (1) ◽  
pp. 418-447 ◽  
Author(s):  
Irfan Anjum Badruddin
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Outer Boundary ◽  
Governing Equations ◽  
Content Type ◽  
Porous Cavity ◽  
Various Boundary Conditions ◽  
Heating Source ◽  
Transfer Behavior ◽  
Vertical Walls

Purpose The purpose of this paper is to investigate the heat transfer in an arbitrary cavity filled with porous medium. The geometry of the cavity is such that an isothermal heating source is placed centrally at the bottom of the cavity. The height and width of the heating source is varied to analyses its effect on the heat transfer characteristics. The investigation is carried out for three different cases of outer boundary conditions such as two outside vertical walls being maintained at cold temperature To, two vertical and top horizontal surface being heated to. To and the third case with top surface kept at To but other surfaces being adiabatic. Design/methodology/approach Finite element method is used to solve the governing equations. Findings It is observed that the cavity exhibits unique heat transfer behavior as compared to regular cavity. The cases of boundary conditions are found to affect the heat transfer rate in the porous cavity. Originality/value This is original work representing the heat transfer in irregular porous cavity with various boundary conditions. This work is neither being published nor under review in any other journal.

Heat transfer in a porous cavity in presence of square solid block

2019 ◽  
Vol 29 (2) ◽  
pp. 640-656 ◽  
Author(s):  
Ameer Ahamad Nandalur ◽  
Sarfaraz Kamangar ◽  
Irfan Anjum Badruddin
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Porous Medium ◽  
Vertical Surface ◽  
Cool Temperature ◽  
Governing Equations ◽  
Content Type ◽  
Porous Cavity ◽  
Hot Surface ◽  
Solid Block

Purpose The purpose of this study was to analyze the heat transfer in a square porous cavity that has a solid block placed at its center. The prime focus of this study is to investigate the effect of size of the square solid block and other physical parameters on the heat transfer rate from the hot surface into the porous medium. The left vertical surface of cavity is maintained at a hot temperature and the right vertical surface at a cool temperature, Tc. The finite element method is used to simplify the governing equations and is solved iteratively. It is noted that the size of the solid block plays a vital role in dictating the heat transfer from the hot surface to porous medium. Design/methodology/approach The current work is based on finite element formulation of a square porous cavity that has a solid square block placed at its center. Governing equations were solved iteratively. Findings The size of the solid block has a pronounced effect on the heat transfer behavior inside the porous cavity. Originality/value This study highlights the heat transfer due to a conducting square solid block at mid of porous cavity.

Unsteady and porous media flow of reactive non-Newtonian fluids subjected to buoyancy and suction/injection

2015 ◽  
Vol 25 (7) ◽  
pp. 1682-1704 ◽  
Author(s):  
Tirivanhu Chinyoka ◽  
Daniel Oluwole Makinde
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Boundary Conditions ◽  
Flow Velocity ◽  
Flow System ◽  
Finite Difference Methods ◽  
Porous Media Flow ◽  
Convective Boundary Conditions ◽  
Convective Boundary ◽  
Content Type

Purpose – The purpose of this paper is to examine the unsteady pressure-driven flow of a reactive third-grade non-Newtonian fluid in a channel filled with a porous medium. The flow is subjected to buoyancy, suction/injection asymmetrical and convective boundary conditions. Design/methodology/approach – The authors assume that exothermic chemical reactions take place within the flow system and that the asymmetric convective heat exchange with the ambient at the surfaces follow Newton’s law of cooling. The authors also assume unidirectional suction injection flow of uniform strength across the channel. The flow system is modeled via coupled non-linear partial differential equations derived from conservation laws of physics. The flow velocity and temperature are obtained by solving the governing equations numerically using semi-implicit finite difference methods. Findings – The authors present the results graphically and draw qualitative and quantitative observations and conclusions with respect to various parameters embedded in the problem. In particular the authors make observations regarding the effects of bouyancy, convective boundary conditions, suction/injection, non-Newtonian character and reaction strength on the flow velocity, temperature, wall shear stress and wall heat transfer. Originality/value – The combined fluid dynamical, porous media and heat transfer effects investigated in this paper have to the authors’ knowledge not been studied. Such fluid dynamical problems find important application in petroleum recovery.

scholarly journals The convection of a Bingham fluid in a differentially-heated porous cavity

2016 ◽  
Vol 26 (3/4) ◽  
pp. 879-896 ◽  
Author(s):  
D. Andrew S. Rees
Keyword(s):  
Rayleigh Number ◽  
Yield Stress ◽  
Piecewise Linear ◽  
Rectangular Cavity ◽  
Content Type ◽  
Multigrid Algorithm ◽  
Bingham Number ◽  
Steady Solutions ◽  
Darcy Flux ◽  
Darcy Rayleigh Number

Purpose – The purpose of this paper is to determine the manner in which a yield stress fluid begins convecting when it saturates a porous medium. A sidewall-heated rectangular cavity is selected as the testbed for this pioneering work. Design/methodology/approach – Steady solutions are obtained using a second order accurate finite difference method, line relaxation based on the Gauss-Seidel smoother, a Full Approximation Scheme multigrid algorithm with V-cycling and a regularization of the Darcy-Bingham model to smooth the piecewise linear relation between the Darcy flux and the applied body forces. Findings – While Newtonian fluids always convect whenever the Darcy-Rayleigh number is nonzero, Bingham fluids are found to convect only when the Darcy-Rayleigh number exceeds a value which is linearly dependent on both the Rees-Bingham number and the overall perimeter of the rectangular cavity. Stagnation is always found in the centre of the cavity and in regions close to the four corners. Care must be taken over the selection of the regularization constant. Research limitations/implications – The Darcy-Rayleigh number is restricted to values which are at or below 200. Originality/value – This is the first investigation of the effect of yield stress on nonlinear convection in porous media.

scholarly journals Like ships passing in the night: toward a truly dyadic perspective on feedback dynamics

2018 ◽  
Vol 16 (4) ◽  
pp. 334-342 ◽  
Author(s):  
Frederik Anseel ◽  
Lien Vossaert ◽  
Elias Corneillie
Keyword(s):  
Organizational Behavior ◽  
Design Methodology ◽  
Systematic Approach ◽  
Empirical Work ◽  
Dynamic Processes ◽  
Management Research ◽  
Feedback Seeking ◽  
Dynamic Approach ◽  
Content Type ◽  
Feedback Interventions

Purpose This paper aims to extend the argument of DeNisi & Smith Sockbeson, who called to bridge the gap between feedback-seeking and feedback-giving research. The paper pushes their argument further by suggesting that future feedback research should systematically adopt a dyadic and dynamic approach to enhance the understanding of feedback episodes. Design/methodology/approach This paper reviews previous empirical work in the feedback domain and develops conceptual arguments for linking feedback-seeking and feedback intervention research. Findings Drawing upon previous work, the authors conclude that the current depiction of feedback processes in the literature might have been overly static and one-sided. Furthermore, it is argued that feedback research might have not kept up to date with recent conceptual and methodological developments in dyadic organizational behavior research. Research limitations/implications This paper builds on the argument of DeNisi & Smith Sockbeson, in turn contributing to a more complete picture of how feedback processes unfold in organizations. While this paper profiles a few studies that have begun to bridge the disconnect between feedback-seeking and feedback-giving research, one of its limitations is that it does not adopt a systematic approach in reviewing all potential methodologies. Originality/value This paper provides a first step toward studying feedback episodes as dyadic and dynamic processes. In doing so it helps solving one of the long-standing puzzles in management research namely why feedback interventions are sometimes detrimental to performance.

Knowledge-intensive entrepreneurship: a systematic review and future directions

2019 ◽  
Vol 17 (1) ◽  
pp. 50-67
Author(s):  
Caio Sousa ◽  
Luciana Soares Silva
Keyword(s):  
Systematic Review ◽  
Systematic Approach ◽  
Future Directions ◽  
Content Type ◽  
Future Studies ◽  
Knowledge Intensive ◽  
Relationship Of ◽  
The Relationship ◽  
Knowledge Intensive Entrepreneurship ◽  
Focal Issue

Purpose This study aims to propose a framework based on the main theoretical and empirical contributions present in the literature and articulate the main paths for future studies in knowledge-intensive entrepreneurship (KIE). Design/methodology/approach Using the systematic review method from a survey of 85 articles, related to the KIE focal issue, originated from the Web of Science, it was possible to exhaustively analyze the studies and to divide the theme into key categories. Findings The present research has raised the relationship of five categories to KIE conceptualizations; the data suggest that although the literature indicates a distancing from KIE research, there are multidisciplinary themes and approaches interlinked in the studies. Originality/value The systematic approach in the main theoretical and empirical contributions in KIE enabled us to relate five categories (entrepreneurs, innovation, internationalization, location and triple alliance), and finally, to understand the gaps suggested by the researchers.

Role of breakfast in hotel selection: systematic review

2019 ◽  
Vol 13 (2) ◽  
pp. 204-217
Author(s):  
Fernanda Leite-Pereira ◽  
Filipa Brandao ◽  
Rui Costa
Keyword(s):  
Systematic Review ◽  
Design Methodology ◽  
Systematic Approach ◽  
Web Of Science ◽  
Relative Role ◽  
Apparent Contradiction ◽  
Content Type ◽  
Isi Web Of Science ◽  
Relevant Factors

Purpose Diverse factors may influence travelers when choosing a hotel. Even though breakfast is often commented on in hotel and booking sites, its relative role in hotel selection is rarely studied. This paper aims to determine which attributes clients consider essential regarding the option towards a hotel and their hierarchy namely of breakfast. Design/methodology/approach A systematic review was performed in Scopus, ISI-Web of Science and Google Scholar, including relevant original manuscripts published in all languages between 1998 and 2018. Findings Out of 337 initial references, 25 manuscripts were included. Features related to facilities and services were considered in most manuscripts with 21 and 20 citations, respectively, as being the more relevant factors in hotel selection. Room and accommodation were ranked first as the most important characteristic regarding the option for a hotel, whereas breakfast was only referred to in two articles, published in 2015 and 2017, rated in the tenth and fourth positions, respectively. Research limitations/implications Breakfast seems to be addressed in recent published manuscripts, what may reflect a trend toward its evaluation in travelling experiences. More studies should address the relevance of breakfast and food to (diverse type of) costumers, and managers should also consider these factors when advertising their hotels. Originality/value To the best of the authors’ knowledge, this is the first systematic approach to this question, emphasizing the apparent contradiction of breakfast being often cited in booking sites and not adequately studied in tourism research.

Human factors automatic evaluation for entire maintenance processes in virtual environment

2014 ◽  
Vol 34 (4) ◽  
pp. 357-369 ◽  
Author(s):  
Shiguang Qiu ◽  
Yunfei Yang ◽  
Xiumin Fan ◽  
Qichang He
Keyword(s):  
Human Factors ◽  
Virtual Environment ◽  
Systematic Approach ◽  
Evaluation Model ◽  
Information Model ◽  
Automatic Evaluation ◽  
Hydraulic Motor ◽  
Content Type ◽  
Computer Environment ◽  
Virtual Maintenance

Purpose – The paper aims to propose a systematic approach for human factors (HFs) automatic evaluation for entire maintenance processes in virtual environment. Design/methodology/approach – First, a maintenance process information model is constructed to map real maintenance processes into computer environment. Next, based on this information model, the automatic evaluation methods for visibility, operation comfort and reachability are presented. All evaluation results are weighted and added up to establish a comprehensive HFs evaluation model. Then, the methods mentioned above are realized as an HFs evaluation module, which is integrated into virtual maintenance simulation platform, software developed by our lab. Findings – An application in HFs evaluation of repairing hydraulic motor on container spreader is implemented, and an on-site survey is carried out. The comparison between the result from the survey and the result we get using the presented methods shows that our solution can support HFs fast assessment accurately and effectively. Practical implications – Through evaluating maintenance operation processes, engineers can better analyze and validate the maintainability design of complex equipment, and some potential ergonomic issues can be found and dealt earlier. Originality/value – The paper contributes to present a systematic approach to achieve HFs fast and accurate evaluation for entire maintenance processes, rather than for a few maintenance postures.

A review of facilities management performance measurement

2019 ◽  
Vol 37 (4) ◽  
pp. 490-511 ◽  
Author(s):  
Daniel Amos ◽  
Zairul Nisham Musa ◽  
Cheong Peng Au-Yong
Keyword(s):  
Performance Measurement ◽  
Design Methodology ◽  
Systematic Approach ◽  
Web Of Science ◽  
Future Research ◽  
Facilities Management ◽  
Content Type ◽  
Slow Pace ◽  
The Past ◽  
Key Issues

Purpose The purpose of this paper is to present a comprehensive review of facilities management (FM) performance measurement (PM) research within the past two decades to understand existing gaps in FM PM literature. Design/methodology/approach The paper employs a systematic approach to review papers in FM PM published from 1997 to 2017. The articles published in selected peer-reviewed international journals in the last 20 years were collected by conducting literature search in the Web of Science and Scopus databases. The content of the papers were scrutinized to understand the gap in literature. Findings The review depicts a slow pace of FM PM research characterized by diverse and fragmented performance measures, whereas the existing PM frameworks are at the nascent stage. Research limitations/implications The judgments of the paper are based on the 54 papers selected for the critical review and analysis that should be treated as key issues in FM PM research agenda. The review also excludes energy management. Originality/value The paper identifies the gaps in the current PM literature in FM and set propositions for future research which is of utility and relevance to FM researchers more especially on the existing conceptual frameworks. To the best of the authors’ knowledge, this paper is the first attempt to conduct a review on FM PM in the extant literature.

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