483 research outputs found

    Simulation of 2-dimensional viscous flow through cascades using a semi-elliptic analysis and hybrid C-H grids

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    A semi-elliptic formulation, termed the interacting parabolized Navier-Stokes (IPNS) formulation, is developed for the analysis of a class of subsonic viscous flows for which streamwise diffusion is neglible but which are significantly influenced by upstream interactions. The IPNS equations are obtained from the Navier-Stokes equations by dropping the streamwise viscous-diffusion terms but retaining upstream influence via the streamwise pressure-gradient. A two-step alternating-direction-explicit numerical scheme is developed to solve these equations. The quasi-linearization and discretization of the equations are carefully examined so that no artificial viscosity is added externally to the scheme. Also, solutions to compressible as well as nearly compressible flows are obtained without any modification either in the analysis or in the solution process. The procedure is applied to constricted channels and cascade passages formed by airfoils of various shapes. These geometries are represented using numerically generated curilinear boundary-oriented coordinates forming an H-grid. A hybrid C-H grid, more appropriate for cascade of airfoils with rounded leading edges, was also developed. Satisfactory results are obtained for flows through cascades of Joukowski airfoils

    Beginning of the End of Cost Competitiveness in CEE Countries - Analysis of Dependence between Labor Costs and Internationalization of the Region

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    In order to exemplify the above econometric model I carried out empirical analysis of the companies listed on the Warsaw Stock Exchange, identifying the companies for which efficiency-seeking is the main internationalization motive. The analysis of internationalization of 26 companies during the years 1990-2010 clearly shows that a significant part of investments is located outside the territory of Poland, in the countries with lower labor costs. This fact confirms that CEE countries will gradually become less and less attractive in terms of costs not only for MNEs from developed countries but also for the companies originating from transition economies.Głównym celem artykułu jest weryfikacja, czy niski poziom kosztów pracy w Europie Środkowej i Wschodniej będący do tej pory jednym z czynników wpływających na konkurencyjność tego regionu pozostanie nim w dłuższej perspektywie czasowej. W pracy na podstawie próby wszystkich państw UE zbadano zależność pomiędzy poziomem internacjonalizacji (stan odpływu BIZ per capita) a kosztami pracy w sektorze przedsiębiorstw i GNP per capita. Analiza regresji potwierdziła istnienie zależności pomiędzy wyżej wymienionymi czynnikami. Oznacza to, że stopniowy wzrost kosztów pracy w państwach Europy Środkowej i Wschodniej prowadził będzie do stopniowego odpływu BIZ z tego regionu do państw bardziej konkurencyjnych kosztowo. W celu egzemplifikacji powyższych zależności w pracy dodatkowo przedstawiono analizę inwestycji zagranicznych polskich spółek notowanych na GPW, z których to 26 dokonało inwwestycji zagranicznych o wyraźnych motywach związanych z obniżeniem kosztów produkcji. Fakt ten potwierdza powolny spadek konkurencyjności kosztowej polskiej gospodarki, tym samym zmusza do poszukiwania nowych rozwiązań instytucjonalnych mogących utrzymać konkurencyjność polskiej gospodarki w długim okresie

    Foreign Direct Investment by Emerging Economy Multinationals: Coping with the Global Crisis

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    Even before the onset of the global crisis, the global market for foreign direct investment (FDI) had undergone significant changes. Foremost amongst these changes was the increasing importance of emerging market multinationals (MNEs). While outward foreign direct investment (OFDI) from these markets is, in itself, not new, the magnitude that this phenomenon achieved prior to the crisis and its resilience in the face of the global crisis suggest that this is not a temporary occurrence but rather a sign of a fundamental change that is taking place in the global OFDI market. However, emerging markets are not homogenous: in addition to the rise in OFDI from emerging markets, the formation of new regional groupings has led to the emergence of fresh investment patterns. This chapter examines changes taking place in global FDI flows and looks at the impact of the crisis in the context of profound structural changes; it also focuses on the response of emerging markets and the enormous risks and challenges that lie ahead. It is vital to note that this crisis is ongoing, and it is too early to predict the final contours it will leave in its wake on the FDI landscape

    Computational Fluid-Structure Interaction of a Deformable Flapping Wing for Micro Air Vehicle Applications

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    Motivated by micro air vehicle applications, a fluid-structure coupling procedure between a Navier- Stokes solver and a three-dimensional FEM beam solver is presented along with selected results highlighting some of the aerodynamics implications. The fluid model includes laminar, the k -ε turbulence closure, and a filter-based k -ε closure. The structural model is based on an asymptotic approximation to the equations of elasticity. Using the slenderness as the small parameter, the equations are decomposed into two independent variational problems, corresponding to (i) crosssectional, small-deformation and (ii) longitudinal, large deformation analyses. A model example problem corresponding to a NACA0012 wing of aspect ratio 3 in pure heave motion is presented and the results compared against available experiment data. Quantitative comparisons with experiment are done for the rigid wing and the implications of wing flexibility on aerodynamics are presented in a qualitative sense. It was observed that phase lag of the wing tip displacement relative to the flapping motion becomes more pronounced as the fluid density increases. Copyright © 2008 by the American Institute of Aeronautics and Astronautics, Inc.Published versio

    From national monopoly to Multinational Corporation: how regulation shaped the road towards telecommunications internationalization

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    One of the consequences of major regulatory reform of the telecommunications sector from the end of the 1970s – particularly, privatization, liberalization and deregulation – was the establishment of a new business environment which permitted former national telecommunications monopolies to expand abroad. From the 1990s, a number of these firms, particularly those based in Europe, joined the rankings of the world’s leading Multinational Corporations. Their internationalization was uneven, however: while some firms internationalised strongly, others ventured abroad much slower. This article explores how the regulatory framework within which telecommunications incumbents evolved over the long-term shaped their subsequent, uneven, paths to internationalization. Two case studies representing ´maximum variation´ are selected: Telefónica, whose early and unrelenting expansion transformed it into one of the world’s most international of Multinational Corporations, and BT, whose overseas ventures failed and, with eroding domestic market share, forced the firm to partially retreat, becoming the least international of the large European incumbents. Long-term ownership, access to capital, management style and exposure to liberalization strongly influenced firms’ approaches to internationalizatio

    Energy security and shifting modes of governance

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    The concept of energy security fits uneasily into contemporary security debates. It is neither a clearly traditional nor a fully ‘non-traditional’ security issue. There are also limits to the social constructedness of the concept. This article argues that, while it is important to identify the differing securitizations of energy, these must be contextualized within the material realities and the differing historical modes of governance of the political economy of resources. This is essential for understanding the differing meanings accorded to energy security, the shifting modes through which energy is governed, and the extent to which energy security concerns drive international politics. In this context, contemporary concerns over energy security have both material and ideological dimensions: anxiety over the dual shift of power from West to East and from resource-importing to resource-exporting countries; and concern over the normative weakening of the neo-liberal mode of energy governance
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