Spatiotemporal properties of multiscale two-dimensional ows

The extraordinary complexity of turbulence has motivated the study of some of its key features in flows with similar structure but simpler or even trivial dynamics. Recently, a novel class of such flows has been developed in the laboratory by applying multiscale electromagnetic forcing to a thin layer of conducting fluid. In spite of being stationary, planar, and laminar these flows have been shown to resemble turbulent ones in terms of energy spectra and particle dispersion. In this thesis, some extensions of these flows are investigated through simulations of a layer-averaged model carried out using a bespoke semi-Lagrangian spline code. The selected forcings generalise the experimental ones by allowing for various kinds of self-similarity and planetary motion of the multiple scales. The spatiotemporal structure of the forcings is largely reflected on the flows, since they mainly arise from a linear balance between forcing and bottom friction. The exponents of the approximate power laws found in the wavenumber spectra can thus be related to the scaling and geometrical forcing parameters. The Eulerian frequency spectra of the unsteady flows exhibit similar power laws originating from the sweeping of the multiple flow scales by the forcing motions. The disparity between fluid and sweeping velocities makes it possible to justify likewise the observed Lagrangian power laws, but precludes a proper analogy with turbulence. In the steady case, the absolute dispersion of tracer particles presents ballistic and diffusive stages, while relative dispersion shows a superquadratic intermediate stage dominated by separation bursts due to the various scales. In the unsteady case, the absence of trapping by fixed streamlines leads to appreciable enhancement of relative dispersion at low and moderate rotation frequency. However, the periodic reversals of the large scale give rise to subdiffusive absolute dispersion and severely impede relative dispersion at high frequency

Back to Life: Leadership from a Process Perspective

Process thinking has given us signals regarding how to make critical judgements about, or else how to grasp actively and immanently, an organisational world on the move. The perspective of a world that is constantly changing draws our attention to the sensate feeling of time and to the creative use of the immediate past, which is no more and the immediate future, which is not yet, in our experience of the here and now. The current discussion uses the concept of process to contribute a more critical understanding of the actual occasion of leadership behaviour, anticipating this will offer both a route out of the popular obsession with individual leader-work and interactive studies of leadership as a predicate dependent on particular leaders and followers in interpersonal contexts, and toward the creative potential of leadership as process itself.

Reluctant Bedfellows or Model Marriage? Postmodern Thinking Applied to Mainstream Public Sector Health Services Research Settings

An important mobilisation of postmodernism is as a way of thinking that pays particular attention to the play of differences in human thought and experience. Informed by the Derridean theory of deconstruction, the current discussion critically examines an original piece of health services research undertaken by the author, which aimed to derive propositions about how health service researchers disseminated research information to those in daily practice in the United Kingdom (UK) National Health Service (NHS). The objective is to provide an analytical review of those tacit and oftentimes suppressed, marginalized or hidden, forms of knowledge that may be conveniently overlooked or glossed over in mainstream health services research, which is largely produced by university-based researchers who remain subject to traditional academic pressures. Following a review of the theory and practice of deconstruction, Boje and Dennehy’s (1994) specific seven-point ‘deconstruction methodology’, based on drawing empirical data through bipolar opposite themes, is deployed before concluding with a consideration of the implications of a postmodern analysis of mainstream healthcare practice, policy and organisation settings, which have a central role to play in delivering service improvement in the new financial environment.

Lines of Flight: Everyday Resistance along England’s Backbone

The visual and the cultural impact of ‘social industry’ has made a permanent impression on the landscape and on individual minds, whether for ill or for good, particularly in the Peak and Pennines region of northern England. In the current research we examine this impact and consider how both its visible and less apparent effects took hold and how they set in motion an ongoing process of productive/consumptive estrangement from life’s primordial forces, which continue to be alien and obscure, or else appear arcane and overly nostalgic to present-day life. Drawing on the methodology of a short film (incorporating narrative and verse) and using rock climbing as an illustration, we will invoke several, radically dynamic ‘lines of flight’ to open up and articulate an aesthetic appreciation of concrete experience in the fight against coding and to engender a call for action and passion so that we might come to a renewed belief in free activity, which can prompt us, in turn, to think about how we live and work and how we might change things.

Leadership then at all events

Theory purporting to identify leadership remains over-determined by one of two underlying fallacies. Traditionally, it hypostatizes leadership in psychological terms so that it appears as the collection of attributes belonging to an independent, discrete person. By contrast, contemporary perspectives approach leadership by focusing on the intermediary relations between leaders and followers. We retreat from both of these conceptions. Our approach perceives these terms as continuous within each other and not merely as adjacent individuals. The upshot is that leadership should be understood as a more fundamental type of relatedness, one that is glimpsed in the active process we are here calling events. We suggest further work consistent with these ideas offers an innovative and useful line of inquiry, both by extending our theoretical understanding of leadership, but also because of the empirical challenges such a study invites.

The EC Water Framework Directive and its implications for the Environment Agency

The bulk of the European Community's water policy legislation was developed between the mid 1970s and the early 1990s. These directives addressed specific substances, sources, uses or processes but caused problems with differing methods definitions and aims. The Water Framework Directive (WFD) aims to resolve the piecemeal approach. The Environemnt Agency (EA) welcomes and supported the overall objective of establishing a coherent legislative framework. The EA has been discussing the implications of the WFD with European partners and has developed a timetable for the implementation and a special team will commission necessary research

Comparison between different approaches for the evaluation of the hot spot structural stress in welded pressure vessel components

Fatigue cracks in welds often occur at the toe of a weld where stresses are difficult to calculate at the design stage. To circumvent this problem the ASME Boiler and PV code Section VIII Division 2 Part 5 [1] uses the structural stress normal to the expected crack to predict fatigue life using elastic analysis and as welded fatigue curves. The European Unfired Pressure Vessel Code [2] uses a similar approach. The structural stress excludes the notch stress at the weld toe itself. The predicted fatigue life has a strong dependency on the calculated value of structural stress. This emphasizes the importance of having a unique and robust way of extracting the structural stress from elastic finite element results. Different methods are available for the computation of the structural hotspotstress at welded joints. These are based on the extrapolation of surface stresses close to the weld toe, on the linearisation of stresses in the through-thickness direction or on the equilibrium of nodal forces. This paper takes a critical view on the various methods and investigates the effects of the mesh quality on the value of the structural stress. T-shaped welded plates under bending are considered as a means for illustration

Impurity transport in plasma edge turbulence

The turbulent transport of minority species/impurities is investigated in 2D drift-wave turbulence as well as in 3D toroidal drift-Alfven edge turbulence. The full effects of perpendicular and -- in 3D -- parallel advection are kept for the impurity species. Anomalous pinch effects are recovered and explained in terms of Turbulent EquiPartition (TEP)Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France