Mohammad B. Ayani, Javad A. Esfahani and Antonio C.M. Sousa
To show the effect of radiation from the heat source and the variation of fluid properties on the laminar natural convection induced by a line heat source.
Abstract
Purpose
To show the effect of radiation from the heat source and the variation of fluid properties on the laminar natural convection induced by a line heat source.
Design/methodology/approach
The governing equations – Navier‐Stokes and energy equation are discretized in a staggered grid by a control volume approach, and they are solved using a segregated technique. The equations for the fluid and solid (line heat source) phases are solved simultaneously. The three sides of the computational domain are open boundary. Some of the physical and thermo‐physical properties of the fluid (air) such as density, thermal conductivity and viscosity were considered to vary with temperature.
Findings
The present predictions are compared with those using the Boussinesq approximation, with the results for the boundary layer equations, and with the experimental results. The present predictions reveal considerable departure from the Boussinesq‐based solution and from the boundary layer results. This study also shows the radiation exchange between the heat source and surrounding has major effect in the results. Thus, the departure between the experimental and analytical results can be explained by the effect of radiation exchange.
Research limitations/implications
In this work, just studied steady‐state laminar thermal plume with the effects of radiation from heat source and the variation of air properties with temperature while it is propose to extend this work to transient and/or turbulent flow.
Originality/value
The effect of radiation from a line heat source on the flow filed around the source and offers enhancement of design to thermal engineers.
Details
Keywords
Mohamad Javad Baghiat Esfahani and Saeed Ketabi
This study attempts to evaluate the effect of the corpus-based inductive teaching approach with multiple academic corpora (PICA, CAEC and Oxford Corpus of Academic English) and…
Abstract
Purpose
This study attempts to evaluate the effect of the corpus-based inductive teaching approach with multiple academic corpora (PICA, CAEC and Oxford Corpus of Academic English) and conventional deductive teaching approach (i.e., multiple-choice items, filling the gap, matching and underlining) on learning academic collocations by Iranian advanced EFL learners (students learning English as a foreign language).
Design/methodology/approach
This is a quasi-experimental, quantitative and qualitative study.
Findings
The result showed the experimental group outperformed significantly compared with the control group. The experimental group also shared their perception of the advantages and disadvantages of the corpus-assisted language teaching approach.
Originality/value
Despite growing progress in language pedagogy, methodologies and language curriculum design, there are still many teachers who experience poor performance in their students' vocabulary, whether in comprehension or production. In Iran, for example, even though mandatory English education begins at the age of 13, which is junior and senior high school, students still have serious problems in language production and comprehension when they reach university levels.
Details
Keywords
Reza Salehzadeh, Javad Khazaei Pool and Samaneh Soleimani
The purpose of this paper is to examine how brand personality and brand equity affect intentions to revisit a city tourism destination.
Abstract
Purpose
The purpose of this paper is to examine how brand personality and brand equity affect intentions to revisit a city tourism destination.
Design/methodology/approach
Statistical population of this research consisted of those visitors who traveled to Pool city in Iran during Spring 2015. A structural equation model test with maximum likelihood estimation was performed to test the relationship among the research variables using 367 participants.
Findings
The empirical results from the structural model suggest that brand personality and brand equity positively influenced revisit intention. Furthermore, brand personality was a direct antecedent of brand equity.
Originality/value
An integrated model of brand personality, brand equity and revisit intention was tested in a tourism city in the context of a developing economy. The combination of a developing country context and the significance of destination brand enhance the contextual contribution of the paper.
Details
Keywords
Iman Bashtani and Javad Abolfazli Esfahani
This study aims to introduce a novel machine learning feature vector (MLFV) method to bring machine learning to overcome the time-consuming computational fluid dynamics (CFD…
Abstract
Purpose
This study aims to introduce a novel machine learning feature vector (MLFV) method to bring machine learning to overcome the time-consuming computational fluid dynamics (CFD) simulations for rapidly predicting turbulent flow characteristics with acceptable accuracy.
Design/methodology/approach
In this method, CFD snapshots are encoded in a tensor as the input training data. Then, the MLFV learns the relationship between data with a rod filter, which is named feature vector, to learn features by defining functions on it. To demonstrate the accuracy of the MLFV, this method is used to predict the velocity, temperature and turbulent kinetic energy fields of turbulent flow passing over an innovative nature-inspired Dolphin turbulator based on only ten CFD data.
Findings
The results indicate that MLFV and CFD contours alongside scatter plots have a good agreement between predicted and solved data with R2 ≃ 1. Also, the error percentage contours and histograms reveal the high precisions of predictions with MAPE = 7.90E-02, 1.45E-02, 7.32E-02 and NRMSE = 1.30E-04, 1.61E-03, 4.54E-05 for prediction velocity, temperature, turbulent kinetic energy fields at Re = 20,000, respectively.
Practical implications
The method can have state-of-the-art applications in a wide range of CFD simulations with the ability to train based on small data, which is practical and logical regarding the number of required tests.
Originality/value
The paper introduces a novel, innovative and super-fast method named MLFV to address the time-consuming challenges associated with the traditional CFD approach to predict the physics of turbulent heat and fluid flow in real time with the superiority of training based on small data with acceptable accuracy.
Details
Keywords
Reza Salehzadeh, Javad Khazaei Pool, Reihaneh Alsadat Tabaeeian, Mojtaba Amani and Marjan Mortazavi
The purpose of this paper is to investigate the effects of internal marketing and market orientation on organizational performance based on the balanced scorecard (BSC).
Abstract
Purpose
The purpose of this paper is to investigate the effects of internal marketing and market orientation on organizational performance based on the balanced scorecard (BSC).
Design/methodology/approach
A cross-sectional research design, drawing upon a questionnaire survey, was used to collect data from a sample of restaurants. Structural equation modeling was performed to test the relationship among the research variables using findings from the 164 participants.
Findings
The results revealed that internal marketing positively influenced market orientation and performance. In addition, market orientation was a direct antecedent of performance.
Originality/value
The findings provide important academic, practical and political implications for restaurant industry.
Details
Keywords
Navid Moghaddaszadeh, Saman Rashidi and Javad Abolfazli Esfahani
This paper aims to use the second law of thermodynamic to evaluate the potential of gear-ring turbulator in a three-dimensional heat exchanger tube. Accordingly, a numerical…
Abstract
Purpose
This paper aims to use the second law of thermodynamic to evaluate the potential of gear-ring turbulator in a three-dimensional heat exchanger tube. Accordingly, a numerical simulation is performed to obtain the irreversibilities in a three-dimensional heat exchanger tube equipped with some gear-ring turbulators for turbulence regime.
Design/methodology/approach
A numerical simulation is performed to obtain the irreversibilities in a three-dimensional heat exchanger tube equipped with some gear-ring turbulators for turbulence regime. The analysis is carried out based on shear stress transport (SST) k-ω turbulent model. The influences of different parameters containing tooth number, free-space length ratios and Reynolds number on frictional and thermal irreversibilities and Bejan number are discussed.
Findings
The results indicated that the thermal irreversibility reduces by decreasing the tooth number. For example, the thermal entropy generation decreases about 25.81 per cent by decreasing the tooth number in the range of 24 to 0 at Re = 6,000. Moreover, the frictional entropy generation decreases by increasing the tooth number as the gear with more tooth number causes a lower flow disturbance.
Originality/value
The present study arranged a numerical work to study the potential of a gear-ring turbulator in a heat exchanger tube from first and second laws of thermodynamic viewpoint. The turbulent flow is considered for this problem. The literature review showed that the usage of a gear-ring turbulator in a heat exchanger tube is not investigated from the second law of thermodynamic viewpoint by previous studies. As a result, the influences of different parameters containing tooth number, free-space length ratios and Reynolds number on frictional and thermal irreversibilities and Bejan number are discussed.
Details
Keywords
Saman Rashidi, Javad Abolfazli Esfahani, Mohammad Sadegh Valipour, Masoud Bovand and Ioan Pop
The analysis of the flow field and heat transfer around a tube row or tube banks wrapped with porous layer have many related engineering applications. Examples include the reactor…
Abstract
Purpose
The analysis of the flow field and heat transfer around a tube row or tube banks wrapped with porous layer have many related engineering applications. Examples include the reactor safety analysis, combustion, compact heat exchangers, solar power collectors, high-performance insulation for buildings and many another applications. The purpose of this paper is to perform a numerical study on flows passing through two circular cylinders in side-by-side arrangement wrapped with a porous layer under the influence of a magnetic field. The authors focus the attention to the effects of magnetic field, Darcy number and pitch ratio on the mechanism of convection heat transfer and flow structures.
Design/methodology/approach
The Darcy-Brinkman-Forchheimer model for simulating the flow in porous medium along with the Maxwell equations for providing the coupling between the flow field and the magnetic field have been used. Equations with the relevant boundary conditions are numerically solved using a finite volume approach. In this study, Stuart and Darcy numbers are varied within the range of 0 < N < 3 and 1e-6 < Da < 1e-2, respectively, and Reynolds and Prandtl numbers are equal to Re=100 and Pr=0.71, respectively.
Findings
The results show that the drag coefficient decreases for N < 0.6 and increases for N > 0.6. Also, the effect of magnetic field is negligible in the gap between two cylinders because the magnetic field for two cylinders counteracts each other in these regions.
Originality/value
To the authors knowledge, in the open literature, flow passing over two circular cylinders in side-by-side arrangement wrapped with a porous layer has been rarely investigated especially under the influence of a magnetic field.
Details
Keywords
Reza Salehzadeh, Javad Khazaei Pool and Amir Hossein Jafari Najafabadi
The purpose of this research is to explore the relationship between corporate social responsibility (CSR), brand image (BI) and brand equity (BE) in the banking industry of the…
Abstract
Purpose
The purpose of this research is to explore the relationship between corporate social responsibility (CSR), brand image (BI) and brand equity (BE) in the banking industry of the Islamic Republic of Iran.
Design/methodology/approach
Using the deductive approach as the methodology and 213 valid questionnaires returned by customers of Iranian banks in four big cities of Iran, this study tests the relationship between CSR, BI and BE in eight hypotheses. The data were analyzed by the partial least squares method.
Findings
The results of this research show that CSR has a significant direct effect on BI. Also, BI has a significant direct effect on BE.
Originality/value
This research provides valuable insight for studying the relationship between CSR, BI and BE. The results of this study provide a better understanding of the role of CSR in customers’ attitudes and behaviors in the banking industry.
Details
Keywords
Javad Khazaei Pool, Reza Salehzadeh and Rashid Khalilakbar
Limitations of producing energy and the increasing demands in the electricity market in Iran have not only drawn the attention of authorities in the energy industry toward…
Abstract
Purpose
Limitations of producing energy and the increasing demands in the electricity market in Iran have not only drawn the attention of authorities in the energy industry toward optimization of energy consumption, but also created marketing approaches toward these objectives. In this respect, it is important and even necessary to modify energy consumption behaviors. The purpose of this study is to examine the impact of the criteria of an effective Internet advertisement for modification of energy consumption.
Design/methodology/approach
To provide a detailed understanding of customers’ perceptions of energy consumption advertising, a survey study was conducted. The research model is first validated and the formulated hypotheses are tested using the structural equation model (SEM).
Findings
The results showed that the audience’s attention, interest and desire for a piece of advertisement can predict their consumption behavior.
Originality/value
This study is one of the pioneer studies that highlights the importance of advertising toward modification of energy consumption. It seems that, the identification of the causal relations among attention, interest, desire and action, has not yet been clearly validated in the previous literature. This research contributes to the literature by developing and testing a comprehensive research model using SEM. So, the current paper offers vital guidelines to social marketers who are planning to modify energy consumption.
Details
Keywords
Masoud Bovand, Saman Rashidi, Masoomeh Dehesht and Javad Abolfazli Esfahani
The purpose of this paper is to implement the numerical analysis based on finite volume method to compare the effects of stress-jump (SJ) and stress-continuity (SC) conditions on…
Abstract
Purpose
The purpose of this paper is to implement the numerical analysis based on finite volume method to compare the effects of stress-jump (SJ) and stress-continuity (SC) conditions on flow structure around and through a porous circular cylinder.
Design/methodology/approach
In this study, a steady flow of a viscous, incompressible fluid around and through a porous circular cylinder of diameter “D,” using Darcy-Brinkman-Forchheimer’s equation in the porous region, is discussed. The SJ condition proposed by Ochoa-Tapia and Whitaker is applied at the porous-fluid interface and compared with the traditional interfacial condition based on the SC condition in fluid and porous media. Equations with the relevant boundary conditions are numerically solved using a finite volume approach. In this study, Reynolds and Darcy numbers are varied within the ranges of 1 < Re < 40 and 10-7 < Da < 10-2, respectively, and the porosities are e=0.45, 0.7 and 0.95.
Findings
Results show that the SJ condition leads to a much smaller boundary layer within porous medium near the interface as compared to the SC condition. Two interfacial conditions yield similar results with decrease in porosity.
Originality/value
There is no published research in the literature about the effects of important parameters, such as Porosity and Darcy numbers on different fluid-porous interface conditions for a porous cylinder and comparison the effects of SJ and SC conditions on flow structure around and through a porous circular cylinder.