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1 – 10 of over 18000Sagar Saroha, Sawan S. Sinha and Sunil Lakshmipathy
In recent years, the partially averaged Navier–Stokes (PANS) methodology has earned acceptability as a viable scale-resolving bridging method of turbulence. To further enhance its…
Abstract
Purpose
In recent years, the partially averaged Navier–Stokes (PANS) methodology has earned acceptability as a viable scale-resolving bridging method of turbulence. To further enhance its capabilities, especially for simulating separated flows past bluff bodies, this paper aims to combine PANS with a non-linear eddy viscosity model (NLEVM).
Design/methodology/approach
The authors first extract a PANS closure model using the Shih’s quadratic eddy viscosity closure model [originally proposed for Reynolds-averaged Navier–Stokes (RANS) paradigm (Shih et al., 1993)]. Subsequently, they perform an extensive evaluation of the combination (PANS + NLEVM).
Findings
The NLEVM + PANS combination shows promising result in terms of reduction of the anisotropy tensor when the filter parameter (fk) is reduced. Further, the influence of PANS filter parameter f on the magnitude and orientation of the non-linear part of the stress tensor is closely scrutinized. Evaluation of the NLEVM + PANS combination is subsequently performed for flow past a square cylinder at Reynolds number of 22,000. The results show that for the same level of reduction in fk, the PANS + NLEVM methodology releases significantly more scales of motion and unsteadiness as compared to the traditional linear eddy viscosity model (LEVM) of Boussinesq (PANS + LEVM). The authors further demonstrate that with this enhanced ability the NLEVM + PANS combination shows much-improved predictions of almost all the mean quantities compared to those observed in simulations using LEVM + PANS.
Research limitations/implications
Based on these results, the authors propose the NLEVM + PANS combination as a more potent methodology for reliable prediction of highly separated flow fields.
Originality/value
Combination of a quadratic eddy viscosity closure model with PANS framework for simulating flow past bluff bodies.
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The purpose of this paper is to present an academic programme of pansystems research with a lot of new concepts, principles, methods. Universal consideration of…
Abstract
Purpose
The purpose of this paper is to present an academic programme of pansystems research with a lot of new concepts, principles, methods. Universal consideration of philosophy‐mathematics‐technology is set forth with mega‐combination. The emphasis on the transfield internet‐like investigations is developed. Many theory‐methods of pansystems get further concise optimization.
Design/methodology/approach
The concrete contents of the paper include: historical megawave, philosophical stratagems, meta‐mathematics, meta‐methodology, technological realistic principles, unification and differentiation of encyclopedic branches, systems science, information theory, cybernetics, biosystems, generalized vitality, computer and IT, thinking science, logic, OR, AI, PR, DM, modernization of yinyang analysis combining dialectics, sociology, economics, meta‐relativity, generalized quantification and scale theory, general process of birth‐growth‐ageing‐disease‐death, the inheritance and development of 300 scholars' researches, etc.
Findings
All of the topics concerned with are reduced to the actualizations of PVOR – pansystems variational OR: V−d(xy)=*0*/PRR′P′/0**, which is an integrated synthesis of 20‐PanStemCells of PanConcepts and PanMethod, and embodies a specific pansystems summarization for the core of the true and the good. Furthermore, the formula “Pansystems Researches=*(PVOR/0**/Pan54787721/Everything)+*0*=*Pan–netlike connections of thoughts and methods” is expanded with concrete applications.
Originality/value
Provides information on pansystems research.
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All cultures have models of the universe. These models explain the structure of the world, the proper structure of society, the important events in life and the relationship of…
Abstract
All cultures have models of the universe. These models explain the structure of the world, the proper structure of society, the important events in life and the relationship of mystical and rational consciousness. Science has four goals; describing the present, explaining the past, predicting the future and understanding fundamental processes. The Pan‐Acts model maintains that the foundation of reality is an ocean of infinitesimals of energy in ceaseless, random motion. Eight levels of organized phenomena are created by the combinations and permutations of these infinitesimals. This model could serve as a basis for the evolution of a humanistic planetary culture.
Desheng Zhang, Weidong Shi, Dazhi Pan and Guangjian Zhang
– The purpose of this paper is to predict the unstable cavitation shedding flow around a 2D Clark-y hydrofoil.
Abstract
Purpose
The purpose of this paper is to predict the unstable cavitation shedding flow around a 2D Clark-y hydrofoil.
Design/methodology/approach
The paper studies Partially Averaged Navier-Stokes (PANS) model which was employed in the two-phase flow with a homogeneous cavitation model.
Findings
Maximum density ratio affects the mass transfer rate between the liquid and the vapor significantly. The cavitating flow predicted by PANS model can resolve more turbulent scales by decreasing the parameter fk.
Originality/value
The accuracy of numerical prediction is improved by increasing the maximum density ratio and decreasing fk.
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This article discusses the deficiencies of search engines and the importance of metadata before examining three models of metadata retrieval: distributed; distributed data with a…
Abstract
This article discusses the deficiencies of search engines and the importance of metadata before examining three models of metadata retrieval: distributed; distributed data with a centralised index; and centralised union catalogue. In listing the advantages and disadvantages of the distributed model, the Z39.50 protocol is used as an example. The OAI harvest protocol is the example of the second model. Virtual union catalogues are compared with a real one. A pan‐European model is discussed as a way to combine the best of all three models, with EUCAT as its base.
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Joseph G. Nellis, Kathleen M. McCaffery and Robert W. Hutchinson
Completion of the European Single Market Programme in Financial Services has, as expected, set in motion a rationalisation process within the European banking industry, as banks…
Abstract
Completion of the European Single Market Programme in Financial Services has, as expected, set in motion a rationalisation process within the European banking industry, as banks respond to increasing competitive pressures that are having a dampening effect on their traditional business margins. Assesses the importance of these developments in the context of the policy options that are open to the European banking community in the new millennium. In particular, given the prospect of an integrated European economy, now commonly referred to as Euroland, the paper addresses, as its central theme, the potential for the development of pan‐European banks that would then be in a position to configure longer‐term globalisation strategies. Evolution in this direction, if it occurs, is important from a European Central Bank policy perspective, since it would raise systemic risk issues if a small number of European licensed banks became “too big to fail”. We conclude, however, that the most prominent strategic response is likely to be based on the European “regionalisation” of banks and markets rather than pan‐Europeanisation.
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Anuj Kumar Shukla and Anupam Dewan
Convective heat transfer features of a turbulent slot jet impingement are comprehensively studied using two different computational approaches, namely, URANS (unsteady…
Abstract
Purpose
Convective heat transfer features of a turbulent slot jet impingement are comprehensively studied using two different computational approaches, namely, URANS (unsteady Reynolds-averaged Navier–Stokes equations) and SAS (scale-adaptive simulation). Turbulent slot jet impingement heat transfer is used where a considerable heat transfer enhancement is required, and computationally, it is a quite challenging flow configuration.
Design/methodology/approach
Customized OpenFOAM 4.1, an open-access computational fluid dynamics (CFD) code, is used for SAS (SST-SAS k-ω) and URANS (standard k-ε and SST k-ω) computations. A low-Re version of the standard k-ε model is used, and other models are formulated for good wall-refined calculations. Three turbulence models are formulated in OpenFOAM 4.1 with second-order accurate discretization schemes.
Findings
It is observed that the profiles of the streamwise turbulence are under-predicted at all the streamwise locations by SST k-ω and SST SAS k-ω models, but follow similar trends as in the reported results. The standard k-ε model shows improvements in the predictions of the streamwise turbulence and mean streamwise velocity profiles in the zone of outer wall jet. Computed profiles of Nusselt number by SST k-ω and SST-SAS k-ω models are nearly identical and match well with the reported experimental results. However, the standard k-ε model does not provide a reasonable profile or quantification of the local Nusselt number.
Originality/value
Hybrid turbulence model is suitable for efficient CFD computations for the complex flow problems. This paper deals with a detailed comparison of the SAS model with URANS and LES for the first time in the literature. A thorough assessment of the computations is performed against the results reported using experimental and large eddy simulations techniques followed by a detailed discussion on flow physics. The present results are beneficial for scientists working with hybrid turbulence models and in industries working with high-efficiency cooling/heating system computations.
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Mohammad Muzzammil Zekri and Muhammad Najib Razali
This paper aims to examine the dynamic of volatility of Malaysian listed property companies within pan-Asian public property markets based on different volatility perspective over…
Abstract
Purpose
This paper aims to examine the dynamic of volatility of Malaysian listed property companies within pan-Asian public property markets based on different volatility perspective over the past 18 years, especially during the global financial crisis (GFC).
Design/methodology/approach
This study uses several statistical methods and formulas for analysing the dynamic of volatility of Malaysian listed property companies such as exponential generalised autoregressive conditional heteroscedasticity (EGARCH) and Markov-switching (MS) EGARCH. The MS-EGARCH model provides new insights on the volatility dynamics of Malaysian listed property companies compared to conventional volatility modelling techniques, particularly EGARCH. Additionally, this paper will analyse the volatility movement based on three different sub-periods such as pre-GFC, GFC and post-GFC.
Findings
The findings reveal that the markets perform differently under different volatility conditions. Moreover, the application of MS-EGARCH provides a different view on the volatility dynamics compared to the conventional EGARCH model, as MS-EGARCH provides more comprehensive findings, especially during extreme market conditions.
Originality/value
This study contributes to the literature on the dynamics of Malaysian listed property companies within pan-Asian countries, as the approach for assessing the volatility performance based on different volatility conditions is less explored by previous researchers.
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This paper presents a unified framework to model the sintering process of fine powders. The framework is based on classical virtual power principle and its corresponding…
Abstract
This paper presents a unified framework to model the sintering process of fine powders. The framework is based on classical virtual power principle and its corresponding variational principle. Firstly, the classical models of solid state, viscous and liquid phase sintering are reproduced assuming single matter re‐distribution mechanism and using the virtual power principle as the starting point. Then we demonstrate how to obtain the governing equations for microstructural evolution using the variational principle. These provide a common thread through the existing sintering models. Finally a numerical solution scheme is briefly outlined for computer simulation of microstructural evolution using the variational principle as the starting point. The computer simulation can follow the entire sintering process from powder compact to fully dense solid and deal with fully couple multi‐physics processes involving all the possible underlying matter re‐distribution mechanisms. Several examples are provided to demonstrate the deep insights that can be gained into the sintering process by using the numerical tool.
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To study these issues, the authors chose a GFSC with one producer and one material supplier as research object, the supplier will offer green material to the producer and the…
Abstract
Purpose
To study these issues, the authors chose a GFSC with one producer and one material supplier as research object, the supplier will offer green material to the producer and the producer will make green food using green production technology. Then, the authors proposed that consumers' perceived value was determined by the trustworthiness levels of the related green and quality-safety information provided by the supplier and the producer. Then, considering the trustworthiness levels of the green and quality information provided by the supplier and the producer, the authors improved the demand function. Afterwards, we constructed four investment models and their income models are built and then a cost-sharing and revenue-sharing contract (hereafter, CSRS) was adopted to coordinate the GFSC.
Design/methodology/approach
With the growth of consumers environmental awareness and life level, consumers' requirements for green and high quality food are growing. In recently years, to increase consumers' perceived trustworthiness on the product greenness and quality levels, stakeholders in green food supply chain (hereafter, GFSC) start to adopt the blockchain-based traceability system (hereafter, BLTS). For investors, they need to know the investment conditions and how to coordinate the GFSC.
Findings
(1) When the revenue-sharing coefficient is less than three-fourths and higher then a certain vaule, the cost-sharing and revenue-sharing contract can make the GFSC coordinate. (2) The investment cost threshold of the BLTS has a positive relationship with the trustworthiness improvement levels of the green and quality information, the green degree of food products and the quality of food products. (3) In the proposed four investment situations, as the growth of consumers perceived credibility coefficient about the greenness information and the quality information, chain members' revenues will increase. In addition, comparing with co-investing the BLTS, benefits of chain members are lower than them in the sole investment model.
Originality/value
(1) The demand function we proposed can help chain members forecast market demand to support production or ordering decisions. (2) The investment decision policies can offer a theoretical reference for chain members to use the BLTS. (3) The CSRS will offer the theoretical reference for coordinating the supply chain after using the BLTS. Furthermore, our study method can be referenced by other scholars. (4) The study method can offer a method reference for researchers who do a similar discussion in a manufacturing supply chain. Although, our research cannot guide the industrial practices, it can serve as a reference of the similar research in industry.
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