Model turbulent floods with the Smagorinski large eddy closure

Floods, tides and tsunamis are turbulent, yet conventional models are based upon depth averaging inviscid irrotational flow equations. We propose to change the base of such modelling to the Smagorinksi large eddy closure for turbulence in order to appropriately match the underlying fluid dynamics. Our approach allows for large changes in fluid depth to cater for extreme inundations. The key to the analysis underlying the approach is to choose surface and bed boundary conditions that accommodate a constant turbulent shear as a nearly neutral mode. Analysis supported by slow manifold theory then constructs a model for the coupled dynamics of the fluid depth and the mean turbulent lateral velocity. The model resolves the internal turbulent shear in the flow and thus may be used in further work to rationally predict erosion and transport in turbulent floods

Вплив ідеологічної ідентифікації на електоральну діяльність політичних партій в Україні

Струнін П. А. Вплив ідеологічної ідентифікації на електоральну діяльність політичних партій в Україні / П. А. Струнін // Актуальні проблеми політики : зб. наук. пр. / редкол. : С. В. Ківалов (голов. ред..), Л. І. Кормич (заст. голов. ред..), Ю. П. Аленін [та ін.] ; МОНмолодьспорт України ; НУ ОЮА. – Одеса : Фенікс, 2012. – Вип.. 46. – С. 280-287.The effectiveness and intensity of ideological trends in election activities of political parties are explored. The tendencies of formation of «omnivorous» рolitical parties in Ukraine and the effectiveness of such strategies are analyzed

Dynamical system approach and attracting manifolds in K-epsilon model of turbulent jet

We consider the K-epsilon model describing an expansion of a free turbulent jet. Due to the nonlinear nature of turbulent diffusion the turbulent area has a sharp boundary. We seek solutions for the energy, dissipation and momentum as power series in spatial coordinate across the jet with time-dependent coefficients. The coefficients obey a dynamical system with clearly identifiable slow and fast variables. The system is not in a standard form, which excludes rigorous methods of analysis such as centre manifold methods. We put forward a hypothesis that there exists an attracting invariant manifold for trajectories based on a few slow variables. The hypothesis is supported numerically

ICMIC

We construct a model of dispersion of pollutants in turbulent channel flows expressed in terms of depth-averaged concentration. While there are different approaches to averaging, we use the most consistent approach based on centre manifolds. The method describes long-term asymptotics of the concentration as it becomes quickly spread across the entire depth by turbulence and is then weakly distorted by the velocity shear. For the velocity we adopt a classical logarithmic profile across the flow. A partial differential equation is derived describing evolution of the average concentration against time and downstream coordinate. The equation involves high-order spatial derivatives

Fluid flow between active elastic plates

We propose a model of a channel flow between actively moving elastic plates as a framework for blood flow in active human arteries. The main difference from extant models is that our model is autonomous. It is a nonlinear partial differential equation governing the deformation of the plates involving sixth order spatial derivative. The equation has a similar structure to the equation we proposed earlier to simulate another active system—spinning combustion front

Transition to self-similarity of diffusion of tracer in turbulent patch

[Abstract]: A mixing of a passive tracer inside a turbulent patch generated by a localized short-time perturbation is studied numerically and analytically. Two kinds of an initial distribution of a tracer are considered: two-layer and continuous with constant gradient. For the turbulent patch shaped as a layer, it is shown that, regardless of details of initial distributions of a turbulent energy and dissipation, a tracer concentration evolves to self-similar regimes as time elapses. Analytical self-similar solutions to turbulent diffusion equations are found for three symmetric shapes of a turbulent patch: layer, cylinder, and sphere. Distributions of the concentration inside a patch are found to be substantially nonuniform, with a typical ratio of a concentration gradient in the middle of a patch to its initial value of about 0.5

A pragmatic cluster randomised trial evaluating three implementation interventions

Background Implementation research is concerned with bridging the gap between evidence and practice through the study of methods to promote the uptake of research into routine practice. Good quality evidence has been summarised into guideline recommendations to show that peri-operative fasting times could be considerably shorter than patients currently experience. The objective of this trial was to evaluate the effectiveness of three strategies for the implementation of recommendations about peri-operative fasting. Methods A pragmatic cluster randomised trial underpinned by the PARIHS framework was conducted during 2006 to 2009 with a national sample of UK hospitals using time series with mixed methods process evaluation and cost analysis. Hospitals were randomised to one of three interventions: standard dissemination (SD) of a guideline package, SD plus a web-based resource championed by an opinion leader, and SD plus plan-do-study-act (PDSA). The primary outcome was duration of fluid fast prior to induction of anaesthesia. Secondary outcomes included duration of food fast, patients' experiences, and stakeholders' experiences of implementation, including influences. ANOVA was used to test differences over time and interventions. Results Nineteen acute NHS hospitals participated. Across timepoints, 3,505 duration of fasting observations were recorded. No significant effect of the interventions was observed for either fluid or food fasting times. The effect size was 0.33 for the web-based intervention compared to SD alone for the change in fluid fasting and was 0.12 for PDSA compared to SD alone. The process evaluation showed different types of impact, including changes to practices, policies, and attitudes. A rich picture of the implementation challenges emerged, including inter-professional tensions and a lack of clarity for decision-making authority and responsibility. Conclusions This was a large, complex study and one of the first national randomised controlled trials conducted within acute care in implementation research. The evidence base for fasting practice was accepted by those participating in this study and the messages from it simple; however, implementation and practical challenges influenced the interventions' impact. A set of conditions for implementation emerges from the findings of this study, which are presented as theoretically transferable propositions that have international relevance. Trial registration ISRCTN18046709 - Peri-operative Implementation Study Evaluation (POISE

3rd International Conference Elastic Wave Effect on Fluid in Porous Media (EWEF 2012)

Published data of passive seismic, vibration impact on residual oil production as well as selected frequency effect in oil exploration reveal the important role of resonances. If the wave length is much larger than the heterogeneity scale, the resonance appears to be internal one and it has to be accounted for in kinetic part of the dynamics equations. The model is developed to find a general form of dispersion curve, corresponding to the medium resonance at so-called dominant frequencies. The resonance is understood here as a negative dissipation limited by nonlinear generation of higher frequency oscillations. It includes the flux of energy from the Goldstone mode of extremely long waves with neutral stability towards dominant wave spectrum of flickering frequencies. The variants of small ganglia oscillations with surface tension as a restoring force and of gas/oil bubbles under high pressure are compared