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Article
Publication date: 3 December 2018

Aurang Zaib, Rizwan Ul Haq, A.J. Chamkha and M.M. Rashidi

The study aims to numerically examine the impact of nanoparticles on an unsteady flow of a Williamson fluid past a permeable convectively heated shrinking sheet.

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Abstract

Purpose

The study aims to numerically examine the impact of nanoparticles on an unsteady flow of a Williamson fluid past a permeable convectively heated shrinking sheet.

Design/methodology/approach

In sort of the solution of the governing differential equations, suitable transformation variables are used to get the system of ODEs. The converted equations are then numerically solved via the shooting technique.

Findings

The impacts of such parameters on the velocity profile, temperature distribution and the concentration of nanoparticles are examined through graphs and tables. The results point out that multiple solutions are achieved for certain values of the suction parameter and for decelerating flow, while for accelerating flow, the solution is unique. Further, the non-Newtonian parameter reduces the fluid velocity and boosts the temperature distribution and concentration of nanoparticles in the first solution, while the reverse drift is noticed in the second solution.

Practical implications

The current results may be used in many applications such as biomedicine, industrial, electronics and solar energy.

Originality/value

The authors think that the current results are new and significant, which are used in many applications such as biomedicine, industrial, electronics and solar energy. The results have not been considered elsewhere.

Details

World Journal of Engineering, vol. 15 no. 6
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 2 October 2017

Sajjad Miran and Chang Hyun Sohn

The paper aims to study the influence of rounded corners on the flow-induced oscillation of a square cylinder that is free to oscillate in two degrees of freedom.

248

Abstract

Purpose

The paper aims to study the influence of rounded corners on the flow-induced oscillation of a square cylinder that is free to oscillate in two degrees of freedom.

Design/methodology/approach

The finite volume code in conjunction with the moving mesh scheme was implemented via a user-defined function to carry out the computations in two dimensions. The Reynolds number (Re) chosen for the present study is fixed at 100, and the frequency ratio, Fr = fs/fn (where fs is the vortex shedding frequency and fn is the natural frequency of cylinder) is used as a varying parameter. The computational model was validated for flow past a stationary cylinder with R/D = 0 and 0.5, and the results showed good agreement with the literature.

Findings

The aerodynamic characteristics, amplitude response, trajectories of cylinder motion and vortex shedding modes are obtained by conducting a series of simulations under different frequency ratios of the cylinder. It was found that the minimum transverse amplitude, drag force and lift force obtained for a naturally oscillating square cylinder are quite different when compared with a stationary and forced oscillating cylinder, where the maximum drag and lift forces were observed for a square cylinder and a minimum around R/D = 0.2 was observed.

Originality/value

The present work identified the significant effect of the varying frequency ratio and R/D on the VIV modes of the cylinder. It was observed that the cylinder wake exhibits the (2S) vortex shedding mode for R/D = 0 to 0.2 at all Fr, whereas the C (2S) mode appeared for R/D > 0.2 at Fr = 1.1.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 10
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 September 1997

Z. Saad‐Saoud and A.C. Williamson

Presents a new approach for formulating the state space equations associated with electrical systems containing circuits which are coupled only magnetically. Presents an algorithm…

568

Abstract

Presents a new approach for formulating the state space equations associated with electrical systems containing circuits which are coupled only magnetically. Presents an algorithm which automatically determines the state space matrix of a system which can take any topological form. Describes a new way of representing semiconductor devices which gives increased flexibility in system representation, and reduces computation time, together with a technique for satisfactorily accounting for the discontinuous behaviour of semiconductor devices. Illustrates the application of the proposed technique by means of a relatively simple example for which an analytical solution is possible. Compares illustrative test results obtained from more complex circuits with those from simulation to demonstrate further the validity of the method.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 16 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Available. Open Access. Open Access
Article
Publication date: 31 December 2003

Young ll Park and Seung Moon

The 1997-98 financial crisis has had a profound effect on how East Asian economies the role of the IMF and its strategic interests relative to those of the United States in the…

154

Abstract

The 1997-98 financial crisis has had a profound effect on how East Asian economies the role of the IMF and its strategic interests relative to those of the United States in the international financial regime. It has prompted them to create a regional mechanism for financial and monetary cooperation, ranging from deeper policy dialogue and surveillance, to a system of financial cooperation, and common exchange rate arrangements. This paper analyses the economic and strategic motivations behind this and outlines recent developments in financial cooperation in East Asia to provide possible directions for the future.

A network of bilateral swap arrangements under the Chiang Mai Initiative(CMI) needs stronger policy dialogue and surveillance to develop into a regional financing facility, a sort of East Asian IMF. The facility plays a role as an regional lender of last resort, providing short-term funds to a member country facing a temporary liquidity shortage and for market intervention to stabilize foreign exchange rate. East Asian countries need to achieve regional exchange rate stability. In the long run, the region may develop a common currency arrangement, but it cannot be expected in the very near future because there is no convergence of macroeconomic conditions, economic structure and systems. A realistic approach would be for East Asian developing countries to adopt a currency basket system to minimize the impact of dollar/yen exchange rate volatility on their economies. Strong political will and a vision for regional integration will be required to introduce it.

Details

Journal of International Logistics and Trade, vol. 1 no. 1
Type: Research Article
ISSN: 1738-2122

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Book part
Publication date: 9 March 2021

Kanchan Datta

The open objective of liberalization or globalization for the developed nations is the expansion of market or the creation of opportunities to produce and sale more and more goods…

Abstract

The open objective of liberalization or globalization for the developed nations is the expansion of market or the creation of opportunities to produce and sale more and more goods and/or services beyond the domestic market which ultimately lead the nation in the right path of development. On the other hand, this economic environment is a challenge for the developing or less developed or small nations with respect to share of world trade to compete with the developed or large nations with respect to the quality of the product, technology, skill of human resources, etc. There arise tariff impositions to protect the domestic economies to defend against the challenges. Under these circumstances, this chapter tries to investigate the impact of such tariff war measured by trade as a percentage of GDP on the per capita GDP of the nations. It finds that all the variables are cointegrated. The effect depends on how we measure world tariff, for example, the effect of tariff on trade is positive and significant when we measure the world tariff as simple mean of all products but the effect of tariff on trade is negative and statistically significant when we take tariff as weighted mean of all products. Similarly, the effect of tariff on per capita income is positive if tariff is measured with simple average of all products but this effect is negative and significant when it is measured with weighted mean of all products. In this case, imposition of world tariff (weighted mean of all products) declines world per capita income especially in short run.

Details

Global Tariff War: Economic, Political and Social Implications
Type: Book
ISBN: 978-1-80071-314-7

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Article
Publication date: 1 September 2002

Mehmet Özdemir, Mehmet İlyas Bayındır and Güven Önbilgin

This study involves the development of a PSPICE 5.4 package oriented model for the dynamic behaviour of a series excited synchronised slip ring induction motor including the…

809

Abstract

This study involves the development of a PSPICE 5.4 package oriented model for the dynamic behaviour of a series excited synchronised slip ring induction motor including the bridge rectifier for rotor circuit excitation. Furthermore, in this study is aimed at investigating the synchronising behaviour for various rotor connections of a series excited synchronous motor formed by connecting a bridge rectifier input in series with the stator winding of a slip‐ring induction motor whereas the rectifier output feeds the rotor winding. The steady state behaviour of such a scheme in comparison to a separately excited one is well known, but the behaviour during synchronisation requires further study. Presentation of results obtained by a PSPICE based simulation and comparison with experimental results acquired during this study points to a model to account for design variations and additional circuitry. It is convenient to use this model in a drive system. The advantage of this simulation method over the others is that it does not involve the utilisation of specialised programs and mathematical difficulties such as the solution of stiff differential equations. Furthermore, steady state behaviour of the scheme is explained by means of a simple analysis and illustrated by test results.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 21 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 24 June 2019

Niaz B. Khan, Zainah B. Ibrahim, Mian Ashfaq Ali, Mohammed Jameel, Muhammad Ijaz Khan, Ahad Javanmardi and D.O. Oyejobi

Over the past few decades, the flow around circular cylinders has been one of the highly researched topics in the field of offshore engineering and fluid-structure interaction…

279

Abstract

Purpose

Over the past few decades, the flow around circular cylinders has been one of the highly researched topics in the field of offshore engineering and fluid-structure interaction (FSI). In the current study, numerical simulations for flow around a fixed circular cylinder are performed at Reynolds number (Re) = 3900 with the LES method using the ICEM-CFD and ANSYS Fluent tool for meshing and analysis, respectively. Previously, similar studies have been conducted at the same Reynolds number, but there have been discrepancies in the results, particularly in calculating the recirculation length and angle of separation. In addition, the purpose of this study is to address the impact of time interval averaging to obtain the fully converged solution.

Design/methodology/approach

This study presents the LES method, using the ICEM-CFD and ANSYS fluent tool for meshing and analysis.

Findings

In the current study, turbulence statistics are sampled for 25, 50, 75 and 100 vortex-shedding cycles with the CFL value O (1). The recirculation length, angle of separation, hydrodynamic coefficients and the wake behind the cylinder are investigated up to ten diameters. The drag coefficient and Strouhal number are observed to be less sensitive, whereas the recirculation length appeared to be highly dependent on the average time statistics and the non-dimensional time step. Similarly, the mean streamwise and cross-flow velocity are observed to be sensitive to the average time statistics and non-dimensional time step in the wake region near the cylinder.

Originality/value

In the current investigation, turbulence statistics are sampled for 25, 50, 75 and 100 vortex-shedding cycles with the CFL value O (1), using large eddy simulation method at Re = 3900 around a circular cylinder. The impact of time interval averaging to obtain the fully converged mean flow field is addressed. No such consideration is yet published in the literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 27 March 2023

Mostafa Esmaeili and Amir Hossein Rabiee

This study aims to numerically explore the heat transfer characteristics in turbulent two-degree-of-freedom vortex-induced vibrations (VIVs) of three elastically mounted circular…

90

Abstract

Purpose

This study aims to numerically explore the heat transfer characteristics in turbulent two-degree-of-freedom vortex-induced vibrations (VIVs) of three elastically mounted circular cylinders.

Design/methodology/approach

The cylinders are at the vertices of an isosceles triangle with a base and height that are the same. The finite volume technique is used to calculate the Reynolds-averaged governing equations, whereas the structural dynamics equations are solved using the explicit integration method. Simulations are performed for three different configurations, constant mass ratio and natural frequency, as well as distinct reduced velocity values.

Findings

As a numerical challenge, the super upper branch observed in the experiment is well-captured by the current numerical simulations. According to the computation findings, the vortex-shedding around the cylinders increases flow mixing and turbulence, hence enhancing heat transfer. At most reduced velocities, the Nusselt number of downstream cylinders is greater than that of upstream cylinders due to the impact of wake-induced vibration, and the maximum heat transfer improvement of these cylinders is 21% (at Ur = 16), 23% (at Ur = 5) and 20% (at Ur = 15) in the first, second and third configurations, respectively.

Originality/value

The main novelty of this study is inspecting the thermal behavior and turbulent flow–induced vibration of three circular cylinders in the triangular arrangement.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 33 no. 7
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 September 1981

American Airlines Training Ltd., a British subsidiary of American Airlines Training Corporation, opened its new £15 million Flight Training Centre near Gatwick Airport on July 21.

31

Abstract

American Airlines Training Ltd., a British subsidiary of American Airlines Training Corporation, opened its new £15 million Flight Training Centre near Gatwick Airport on July 21.

Details

Aircraft Engineering and Aerospace Technology, vol. 53 no. 9
Type: Research Article
ISSN: 0002-2667

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Book part
Publication date: 5 October 2007

David Shinar

Abstract

Details

Traffic Safety and Human Behavior
Type: Book
ISBN: 978-0-08-045029-2

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