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Article
Publication date: 14 October 2020

Ali Cemal Benim and Sai Bhagavan Maddala

The purpose of this paper is the numerical investigation of the friction laws for incompressible flow in undulated channels, with emphasis on the applicability of the…

Abstract

Purpose

The purpose of this paper is the numerical investigation of the friction laws for incompressible flow in undulated channels, with emphasis on the applicability of the hydraulic diameter concept. A focal point of the study is the derivation of correlations to increase the accuracy of the hydraulic diameter approach.

Design/methodology/approach

Calculations are performed for laminar and turbulent flow, for Reynolds number ranges between 10–2,000 and 5,000–100,000. For turbulent flow, the shear stress transport (SST) model is used. A simple, sawtooth-like undulation shape is considered, where the channel geometry can be described by means of three length parameters. Letting each to take three values, totally 27 geometries are analyzed.

Findings

It is observed that the hydraulic diameter concept applied via analytical or empirical expressions to obtain friction coefficients does not lead to accurate results. For laminar flow, the maximum deviations of analytical values from predicted are about 70%, while 20% deviation is observed on average. For turbulent flow, deviations of Blasius correlation from predicted ones are smaller, but still remarkable with about 20% for maximum deviation and about 10% on average.

Originality/value

Applicability of the hydraulic diameter concept to undulated channels was not computationally explored. A further original ingredient of the work is the derivation of correlations that lead to improved accuracy in calculating the friction coefficient using hydraulic diameter. For laminar flow, the maximum and average deviations of present correlations from numerical predictions are below 5% and 2%, respectively. For turbulent flow, these numbers turn out to be approximately 12% for the maximum deviation and about 2% for the average.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 15 May 2009

J. Batina, M. Batchi, S. Blancher, R. Creff and C. Amrouche

The purpose of this paper is to analyse the convective heat transfer of an unsteady pulsed, laminar, incompressible flow in axisymmetric tubes with periodic sections. The…

Abstract

Purpose

The purpose of this paper is to analyse the convective heat transfer of an unsteady pulsed, laminar, incompressible flow in axisymmetric tubes with periodic sections. The flow is supposed to be developing dynamically and thermally from the duct inlet. The wall is heated at constant and uniform temperature.

Design/methodology/approach

The problem is written with classical homogeneous boundary conditions. We use a shift operator to impose non‐homogeneous boundary conditions. Consequently, this method introduces source terms in the Galerkin formulation. The momentum equations and the energy equation which govern this problem are numerically solved in space by a spectral Galerkin method especially oriented to this situation. A Crank‐Nicolson scheme permits the resolution in time.

Findings

From the temperature field, the heat transfer phenomenon is presented, discussed and compared to those obtained in straight cylindrical pipes. This study showed the existence of zones of dead fluid that locally have a negative influence on heat transfer. Substantial modifications of the thermal convective heat transfer are highlighted at the entry and the minimum duct sections.

Practical implications

Pulsated flows in axisymmetric geometries can be applied to medical industries, mechanical engineering and technological processes.

Originality/value

One of the original features of this study is the choice of Chebyshev polynomials basis in both axial and radial directions for spectral methods, combined with the use of a shift operator to satisfy non‐homogeneous boundary conditions.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 19 no. 3/4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 27 February 2007

Orla Canavan, Maeve Henchion and Seamus O'Reilly

Online shopping is one of the most rapidly growing forms of shopping and provides a global shop window for producers who wish to sell and market their products. This paper…

5343

Abstract

Purpose

Online shopping is one of the most rapidly growing forms of shopping and provides a global shop window for producers who wish to sell and market their products. This paper seeks to investigate the internet as an alternative distribution channel for Irish producers of speciality food products.

Design/methodology/approach

Primary data collection involved consumer focus groups, a producer web audit, producer depth interviews and an e‐mailed online producer survey.

Findings

Consumers of speciality food appear to trade off the convenience and variety potentially available with online shopping for the sales experience associated with more traditional outlets, particularly speciality food outlets and direct sales channels. Nonetheless, the internet can be a significant sales channel for some speciality food producers with products of specific attributes, e.g. high value goods, and products with elaborate and gift‐oriented packaging and for those targeting consumers with previous purchase experience. For the majority of producers, the internet can complement other marketing channels and its role in managing information and relationships may be more important than online sales. Significant challenges exist for speciality food producers to use the internet as a significant sales channel.

Originality/value

The paper considers food as a category comprising a number of different types of products based on their search, credence and experience characteristics. It applies this categorisation to speciality food and examines the influence of these characteristics on the role of the internet as both a sales and marketing channel in Ireland. It uses both consumer and producer perspectives in the analysis.

Details

International Journal of Retail & Distribution Management, vol. 35 no. 2
Type: Research Article
ISSN: 0959-0552

Keywords

Article
Publication date: 7 April 2015

Daniel R Eyers and Andrew T Potter

Whilst there has been considerable research on the use of electronic communications technologies to transfer design files for Additive Manufacturing (AM) between designer…

3822

Abstract

Purpose

Whilst there has been considerable research on the use of electronic communications technologies to transfer design files for Additive Manufacturing (AM) between designer and manufacturer, corresponding studies that explore the resulting implications are limited. Often it is assumed that such an electronic approach is optimal; this paper serves to explore this assumption by reviewing the technical solutions, and identifying the practical implications. The paper aims to discuss these issues.

Design/methodology/approach

The results of a systematic literature review are used to develop four e-commerce channel designs, which are then explored using primary and secondary case studies.

Findings

It is shown that the use of e-commerce with AM has often been oversimplified, suggesting that it will bring about universal benefits through increased efficiency and cost reductions in information transfer, particularly as a result of supply chain disintermediation. Instead, this paper reinforces current e-commerce research suggesting that e-commerce channels can lead to both disintermediation but also re-intermediation of the supply chain; cost reductions and increased efficiency may not automatically follow.

Practical implications

For AM suppliers, channel strategy is likely to be a critical consideration. This paper provides a framework of currently available approaches, links these to the original research, and explains the implications arising from each option.

Originality/value

Whilst there are many technical studies in this area, the potential implications of their adoption are often hypothesized, but seldom explored empirically. This study makes an original contribution through the classification and analysis of the channels from a management perspective.

Details

Journal of Manufacturing Technology Management, vol. 26 no. 3
Type: Research Article
ISSN: 1741-038X

Keywords

Article
Publication date: 18 January 2008

Steven L. Jones and John C. Yeoman

The purpose of this paper is to analyze the OpenIPO process, vis‐à‐vis traditional bookbuilding, and evaluate the suitability of the OpenIPO for various types of…

Abstract

Purpose

The purpose of this paper is to analyze the OpenIPO process, vis‐à‐vis traditional bookbuilding, and evaluate the suitability of the OpenIPO for various types of companies, market conditions, and assets.

Design/methodology/approach

This paper develops the pros and cons of the OpenIPO process, vis‐à‐vis the traditional bookbuilding method, in light of the recent academic literature on securities auctions and the results of the OpenIPOs Hambrecht has conducted, as of mid‐2004.

Findings

The main advantage of the OpenIPO process is that it precludes many of the abuses recently observed in investment banking; however, it is not well suited for complex businesses that are either difficult to value or far removed from the public eye.

Research limitations/implications

Only nine OpenIPOs have been conducted by Hambrecht, or using the Hambrecht method, as of the completion of this paper in mid‐2004.

Practical implications

The paper foresees the OpenIPO process of Hambrecht as supplementing, rather than supplanting, the traditional bookbuilding method. This could come about through the emergence of the OpenIPO as a more viable alternative to bookbuilding, or possibly through some hybrid type of offering in which individual investors play a larger role in price discovery, via the internet, and shares are allocated through both the internet auction and traditional bookbuilding.

Originality/value

Managers considering an initial public offering have a choice between the OpenIPO process of Hambrecht, used in the Google offering, and the traditional bookbuilding process. The choice of the OpenIPO has become more viable not only because of the Google offering, but due to the severe criticism the traditional method has received in recent years for alleged abuses related to the pricing and allocation of shares. This paper assists managers in evaluating this choice IPO offer type while rigorously evaluating the pros and cons of the OpenIPO process and its likely future role in the investment banking industry.

Details

Managerial Finance, vol. 34 no. 2
Type: Research Article
ISSN: 0307-4358

Keywords

Article
Publication date: 13 July 2010

Sumanjeet

The purpose of this paper is to critically examine the Indian IT Act 2000 and IT (Amendment) Act 2008 in the light of e‐commerce perspective to identify the present status…

4484

Abstract

Purpose

The purpose of this paper is to critically examine the Indian IT Act 2000 and IT (Amendment) Act 2008 in the light of e‐commerce perspective to identify the present status of e‐commerce laws in India.

Design/methodology/approach

The paper presents a critical reflection on the current e‐commerce laws in India. The paper is based on the Indian IT Act 2000 and IT (Amendment) Act 2008. The paper presents critical content analysis of various provisions of IT Act in e‐commerce prespective. The paper also highlights legal issues arising from e‐commerce.

Findings

There are many important issues which are critical for the success of e‐commerce that have not been covered or properly addressed by IT Act. The paper reveals that the present IT Act is weak on various fronts and in the absence of sound legal framework e‐commerce cannot create a success story in India. Indian Government must appreciate that for safe and secure business environment on cyberspace, a sound legal framework is needed. This paper suggests that there is strong need to introduce separate laws for e‐commerce in India.

Practical implications

The paper identified various loopholes/problems/weakness of existing e‐commerce laws in India. These issues should be addressed by Goverment of India to protect the interests of Indian software industries, BPO sector and other stakeholders.

Originality/value

The issue identified in the paper is somewhat new, timely and interesting, taking into consideration its importance to economic development in emerging economies such as India.

Details

International Journal of Law and Management, vol. 52 no. 4
Type: Research Article
ISSN: 1754-243X

Keywords

Article
Publication date: 22 July 2021

Sumit Kumar Mehta, Sukumar Pati, Shahid Ahmed, Prangan Bhattacharyya and Jishnu Jyoti Bordoloi

The purpose of this study is to analyze the thermal, hydraulic and entropy generation characteristics for laminar flow of water through a ribbed-wavy channel with the top…

Abstract

Purpose

The purpose of this study is to analyze the thermal, hydraulic and entropy generation characteristics for laminar flow of water through a ribbed-wavy channel with the top wall as wavy and bottom wall as flat with ribs of three different geometries, namely, triangular, rectangular and semi-circular.

Design/methodology/approach

The finite element method-based numerical solver has been adopted to solve the governing transport equations.

Findings

A critical value of Reynolds number (Recri) is found beyond which, the average Nusselt number for the wavy or ribbed-wavy channel is more than that for a parallel plate channel and the value of Recri decreases with the increase in a number of ribs and for any given number of ribs, it is minimum for rectangular ribs. The performance factor (PF) sharply decreases with Reynolds number (Re) up to Re = 50 for all types of ribbed-wavy channels. For Re > 50, the change in PF with Re is gradual and decreases for all the ribbed cases and for the sinusoidal channel, it increases beyond Re = 100. The magnitude of PF strongly depends on the shape and number of ribs and Re. The relative magnitude of total entropy generation for different ribbed channels varies with Re and the number of ribs.

Practical implications

The findings of the present study are useful to design the economic heat exchanging devices.

Originality/value

The effects of shape and the number of ribs on the heat transfer performance and entropy generation have been investigated for the first time for the laminar flow regime. Also, the effects of shape and number of ribs on the flow and temperature fields and entropy generation have been investigated in detail.

Details

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

Keywords

Article
Publication date: 10 December 2019

Muhammad Ijaz Khan, Sohail Ahmad Khan, Tasawar Hayat, Muhammad Waqas and Ahmed Alsaedi

The purpose of this paper is to investigate the entropy optimization in magnetohydrodynamic hybrid nanomaterials flows toward a stretchable surface. The energy expression…

Abstract

Purpose

The purpose of this paper is to investigate the entropy optimization in magnetohydrodynamic hybrid nanomaterials flows toward a stretchable surface. The energy expression is modeled subject to dissipation, heat generation/absorption and Joule heating. Here silicon dioxide (SiO2) and molybdenum disulfide (MoS2) as nanoparticles and propylene glycol (C3H8O2) as base fluid, respectively. Furthermore, the authors discussed the comparative study of molybdenum disulfide and silicon dioxide diluted in propylene glycol. The total entropy optimization rate is computed through implementation of the second law of thermodynamics.

Design/methodology/approach

The nonlinear partial differential system is reduced to an ordinary one through implementation of transformation. Newton built-in shooting method is used for computational results for the given system. Influences of various flow variables on the temperature, Bejan number, velocity, concentration and entropy generation rate are examined graphically for both nanoparticles (SiO2 and MoS2). Gradients of velocity and temperature are computed numerically for various physical parameters. Also, take the comparison between the present and previously published results in tabulated form.

Findings

For higher estimation of ϕ both temperature and velocity are enhanced. Entropy optimization and Bejan number have the opposite outcome for viscosity parameter. Temperature and velocity have opposite behaviors for larger values of magnetic parameter. Molybdenum disulfide (MoS2) is more efficient than silicon dioxide (SiO2).

Originality/value

No such work is yet published in the literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 22 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 4 January 2021

Vikram Kumar and Srivastava Granthi

The purpose of this study is to understand the basics of interactions of groundwater and surface water, which is needed for effective management of water resources.

Abstract

Purpose

The purpose of this study is to understand the basics of interactions of groundwater and surface water, which is needed for effective management of water resources.

Design/methodology/approach

The experimental setup was framed using curved flume and the straight flume, which simulates the model of river and groundwater storage, respectively. The model set up further consists, downstream, central and upstream sections where 14 observation wells, which are arranged at a measured distance from the canal side.

Findings

Exit gradient is higher at downstream when the average head differences between canal and river are 31.9 cm and 35.7 cm. Free seepage height is more in the downstream wells than upstream and central wells. At the downstream section, there is a greater chance of instability of the riverbank.

Research limitations/implications

Results will be used for better planning of hydraulic structural design.

Practical implications

Results will help in storing the large water and better irrigation planning for the water acute states and locations.

Originality/value

The originality is own developed physical model and its own first type to understand the basic of interaction and effects.

Details

World Journal of Engineering, vol. 18 no. 3
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 14 June 2021

Faraz Afshari, Azim Doğuş Tuncer, Adnan Sözen, Halil Ibrahim Variyenli, Ataollah Khanlari and Emine Yağız Gürbüz

Using suspended nanoparticles in the base fluid is known as one of the most efficient ways for heat transfer augmentation and improving the thermal efficiency of various…

305

Abstract

Purpose

Using suspended nanoparticles in the base fluid is known as one of the most efficient ways for heat transfer augmentation and improving the thermal efficiency of various heat exchangers. Different types of nanofluids are available and used in different applications. The main purpose of this study is to investigate the effects of using hybrid nanofluid and number of plates on the performance of plate heat exchanger. In this study, TiO2/water single nanofluid and TiO2-Al2O3/water hybrid nanofluid with 1% particle weight ratio have been used to prepare hybrid nanofluid to use in plate type heat exchangers with three various number of plates including 8, 12 and 16.

Design/methodology/approach

The experiments have been conducted with the aim of examining the impact of plates number and used nanofluids on heat transfer enhancement. The performance tests have been done at 40°C, 45°C, 50°C and 55°C set outlet temperatures and in five various Reynolds numbers between 1,600 and 3,800. Also, numerical simulation has been applied to verify the heat and flow behavior inside the heat exchangers.

Findings

The results indicated that using both nanofluids raised the thermal performance of all tested exchangers which have a various number of plates. While the major outcomes of this study showed that TiO2-Al2O3/water hybrid nanofluid has priority when compared to TiO2/water single type nanofluid. Utilization of TiO2-Al2O3/water nanofluid led to obtaining an average improvement of 7.5%, 9.6% and 12.3% in heat transfer of heat exchangers with 8, 12 and 16 plates, respectively.

Originality/value

In the present work, experimental and numerical analyzes have been conducted to investigate the influence of using TiO2-Al2O3/water hybrid nanofluid in various plate heat exchangers. The attained findings showed successful utilization of TiO2-Al2O3/water nanofluid. Based on the obtained results increasing the number of plates in the heat exchanger caused to obtain more increment by using both types of nanofluids.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 32 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

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