Wind and boundary layers in Rayleigh-Benard convection. Part 2: boundary layer character and scaling

The effect of the wind of Rayleigh-Benard convection on the boundary layers is studied by direct numerical simulation of an L/H=4 aspect-ratio domain with periodic side boundary conditions for Ra={10^5, 10^6, 10^7} and Pr=1. It is shown that the kinetic boundary layers on the top- and bottom plate have some features of both laminar and turbulent boundary layers. A continuous spectrum, as well as significant forcing due to Reynolds stresses indicates undoubtedly a turbulent character, whereas the classical integral boundary layer parameters -- the shape factor and friction factor (the latter is shown to be dominated by the pressure gradient) -- scale with Reynolds number more akin to laminar boundary layers. This apparent dual behavior is caused by the large influence of plumes impinging onto and detaching from the boundary layer. The plume-generated Reynolds stresses have a negligible effect on the friction factor at the Rayleigh numbers we consider, which indicates that they are passive with respect to momentum transfer in the wall-parallel direction. However, the effect of Reynolds stresses cannot be neglected for the thickness of the kinetic boundary layer. Using a conceptual wind model, we find that the friction factor C_f should scale proportional to the thermal boundary layer thickness as C_f ~ lambda_Theta, while the kinetic boundary layer thickness lambda_u scales inversely proportional to the thermal boundary layer thickness and wind Reynolds number lambda_u ~ lambda_Theta^{-1} Re^{-1}. The predicted trends for C_f and \lambda_u are in agreement with DNS results

Technology geography: studying the relationships between technology, location and productivity

Operations management, international management, public policy and economic geography are scientific areas which come together in the study of international technology transfer. This study shows how each of these areas has its own central issues but also has specific parts that are relevant for research on international technology transfer. It is essential for companies to understand the issues of productivity of production technologies employed by them, and for international companies the relationship of productivity of a specific production line and the environment in which this line operates. Simultaneously, it is essential for governments to understand the productivity of their work force and, therefore, to understand the relationship of their country¿s characteristics and the productivity of specific industries. A recommendation is made to add a new focus to the research on international technology transfer called: Technology Geography. Its primary purpose is to investigate the linkages\ud between technology, location and productivity differences

Technology geography: a new area of scientific inquiry

Operations management, international management, public policy and\ud economic geography are four scientific areas, which come together in the study of\ud international technology transfer. This paper shows how each of these four areas has its\ud own central issues but also have specific parts that are relevant for research on\ud international technology transfer. It is essential for companies to thoroughly understand\ud the issues of productivity of production technologies employed by them, and for\ud international companies the relationship of productivity of a specific production line and\ud the environment in which this production line operates. Simultaneously, it is essential for\ud governments to understand the productivity of its work force and therefore to understand\ud the relationship of its country characteristics and the productivity of specific industries (or\ud production technologies). A recommendation is made to add a new focus to the research\ud on international technology transfer called: Technology Geography. Its primary purpose is\ud to investigate the linkages between technology and its location, and its consequences for\ud technology transfer and international production operations

Location analysis of Euroma conference contributions

Operations Management journal rankings are frequently published. Information on Operations\ud Management conferences is much harder to find. This may be due to the difficulties of ranking\ud conferences as well as due to the different motives that contributors to conferences have. In this paper we\ud perform exploratory analysis to determine for one specific conference (EurOMA) who has typically\ud contributed to these conferences. Our analysis focus is on the location of contributors, i.e. country and\ud affiliation. We found that the United Kingdom, Italy and Brazil contribute most authors and papers to the\ud EurOMA conferences. Countries such as Belgium, Denmark, the Netherlands, Sweden are also important\ud contributors. Highest contributing universities include the University of Sao Paulo, Cranfield University,\ud the University of Cambridge and Politecnico di Milano. People who plan to attend the EurOMA\ud conferences can, based on this, expect authors and papers from these countries and universities

Building theories from case study research: the progressive case study

Meredith (1998) argues for more case and field research studies in the field of operations\ud management. Based on a literature review, we discuss several existing approaches to case\ud studies and their characteristics. These approaches include; the Grounded Theory approach\ud which proposes no prior literature review in the substantive area under study (Glaser, 1992:\ud 31) versus Eisenhardt (1989) and Yin (1994) who propose a more directed study with a priori\ud constructs. We then propose an alternative approach which we call the progressive case\ud study. This approach combines strengths of both approaches such as the informative aspect of\ud Grounded Theory and a more plan able approach such as Yin and Eisenhardt propose. We\ud also describe that case studies are not simply a set of interviews and provide examples on the\ud amount of data that might be collected in a detailed case study. Furthermore, we provide\ud direction for analyzing qualitative data in cases

The geographic component of production technology

In today’s global economy manufacturing companies are continuously re-evaluating their\ud location. In many instances companies decide to relocate some or all of their\ud manufacturing activities to so called low labor cost countries. However, the perception that\ud this is cost effective is not always correct. In many instances the costs of producing in low\ud labor cost countries are highly under estimated. In some instances the costs of the\ud production alone, i.e. excluding logistics cost, are already higher than producing in so\ud called high labor cost countries. Previous research suggests that some of the reasons for\ud these higher costs are related to the particular geographic environment. This study is\ud focused on increasing our understanding of the relationship between geographically\ud determined factors and production technology. Understanding the relationship between\ud geographical factors and production factors allows insight into production location and\ud companies may learn to avoid wrongly moving production away from the developed, high\ud labor cost, countries. For governments; knowledge on geographically determined factors\ud places governments in a better position to selectively nurture specific industries based on\ud their geography-production technology relationshi

International technology transfer: building theory from a multiple case-study in the aircraft industry

International technology transfer occurs frequently in international operations, for example in\ud cases of foreign direct investment where companies set-up existing manufacturing lines in new\ud locations. It also occurs in situations of international outsourcing where a new supplier receives\ud product and/or production process information. This technology transfer process often leads to\ud difficulties, for example delays and much higher costs than anticipated. To gain insight into the\ud causes of these difficulties we used a grounded theory approach to describe the process of\ud international production technology transfer. We conducted four case studies in the aircraft\ud industry and analyzed the problems that occurred. We found that technology transfer consists of\ud three phases: preparation, installation and utilization. These three phases are influenced by three\ud types of factors: technological, organizational and environmental. The combination of activities\ud with factors enables an integrated view on international technology transfer. We found that the\ud amount of technology, the accuracy of information, and the extent of organizational and\ud environmental differences have a large impact on the efficiency of the technology transfer\ud process