Three dimensional numerical modelling of full-scale hydraulic structures

This study presents the three-dimensional (3D) hydraulic modelling of free surface flows over complex full-scale hydraulic structures. The work outlined therein forms part of a larger ongoing project which focuses on the assessment of the capabilities of different 3D computational fluid dynamics (CFD) techniques to reproduce hydraulic flows over real scale spillway structures and on the comparison with physical scale models. The aim of the first part of the study, presented in this work, is to evaluate a range of 3D free surface methods with a particular focus on the Eulerian mesh-based Volume of Fluid (VOF) technique. A range of 2D and 3D free surface approaches are initially investigated and validated using an experimental case with a simple geometry. The commercial solver Ansys Fluent and the CFD open source platform OpenFOAM are used to implement the VOF model and the DualSPHysics code is used to conduct simulations using the Lagrangian meshless particle-based Smoothed Particle Hydrodynamics (SPH) method. The hydraulic flow over a real hydraulic structure is subsequently modelled, applying the evaluated model implementations. The scheme consists of a newly constructed flood storage reservoir with a labyrinth weir and extended spillway. Different hydraulic conditions is modelled using a 1:25 physical scale hydraulic model of the prototype which is used to validate the numerical models. In order to remove numerical model uncertainties and provide insight into scale effects, numerical simulations are applied first to the physical scale hydraulic model and then to the full-scale prototype. Results show the model is capable of accurately predicting the interface features as well as the velocity and water depths measured in the physical model. It is observed that full-scale predictions present approximately a 17% increase in velocity and a 20% decrease in water depth compared to the equivalent scaled predictions

Amine catalysis for the organocatalytic diboration of challenging alkenes

© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The generation of in situ sp 2 –sp 3 diboron adducts has revolutionised the synthesis of organoboranes. Organocatalytic diboration reactions have represented a milestone in terms of unpredictable reactivity of these adducts. However, current methodologies have limitations in terms of substrate scope, selectivity and functional group tolerance. Here a new methodology based on the use of simple amines as catalyst is reported. This methodology provides a completely selective transformation overcoming current substrate scope and functional/protecting group limitations. Mechanistic studies have been included in this report

Interpreting Bernard Lonergan’s General Theory of Economic Dynamics: Does it Complete Hayek, Keynes and Schumpeter?

The paper reviews links between Bernard Lonergan's theory of innovative economic growth and cycles, and the ideas of Friedrich Hayek, John Maynard Keynes, and Joseph Schumpeter. They were contemporary economists, who remain influential today. For Lonergan, although markets define what is bought and sold in an exchange economy, production decisions are more fundamental. These decisions are choices about the direction of development, the standard of living, and variations in the distribution of wealth in a modern society. The paper shows how Lonergan's pure cycle theory extends mainstream theory to include a broader view of human behaviour and choice

Larson\u27s Musical Forces in Schlenker\u27s Music Semantics

Larson’s musical forces of gravity, magnetism and inertia link music to metaphors of physical motion. Schlenker’s music semantics is based on similar physical world associations. Because Larson’s forces are about note movements towards harmonic stability, his framework implies note groupings at stable boundaries, given common cadential harmony. These groupings with forces assignments can then be viewed as musical events in Schlenker’s approach, and mapped to structure-preserving external (world) events as required for this author’s semantics. To this end, Schlenker’s truth definition, specifying when an event is ‘true of’ a musical expression, will be adapted. The synthesis amounts to what Schlenker argues for: a formal semantics of music, albeit limited to melodic lines confined to a single key

Engineering a small HOMO-LUMO gap and intramolecular C-H borylation by diborene/anthracene orbital intercalation

The diborene 1 was synthesized by reduction of a mixture of 1,2-di-9-anthryl-1,2-dibromodiborane(4) (6) and trimethylphosphine with potassium graphite. The X-ray structure of 1 shows the two anthryl rings to be parallel and their π(C14) systems perpendicular to the diborene π(B=B) system. This twisted conformation allows for intercalation of the relatively high-lying π(B=B) orbital and the low-lying π* orbital of the anthryl moiety with no significant conjugation, resulting in a small HOMO-LUMO gap (HLG) and ultimately an anthryl C-H borylation. The HLG of 1 was estimated to be 1.57 eV from the onset of the long wavelength band in its UV-vis absorption spectrum (THF, λonset = 788 nm). The oxidation of 1 with elemental selenium afforded diboraselenirane 8 in quantitative yield. By oxidative abstraction of one phosphine ligand by another equivalent of elemental selenium, the B-B and C1-H bonds of 8 were cleaved to give the cyclic 1,9-diborylanthracene 9

Diboryldiborenes: pi-conjugated B4 chains isoelectronic to the butadiene dication

sp2–sp3 diborane species based on bis(catecholato)diboron and N-heterocyclic carbenes (NHCs) are subjected to catechol/bromide exchange selectively at the sp3 boron atom. The reduction of the resulting 1,1-dibromodiborane adducts led to reductive coupling and isolation of doubly NHC-stabilized 1,2-diboryldiborenes. These compounds are the first examples of molecules exhibiting pi-electron delocalization over an all-boron chain

Determination of Scale Effects for a Scaled Physical Model of a Labyrinth Weir Using CFD

In the present study the three dimensional (3D) Computational Fluid Dynamics (CFD) Volume of Fluid (VOF) model is employed to reproduce the complex hydraulic flows over a labyrinth weir and a spillway for two flow rates, 40 m3/s and the PMF event of the scheme, 159.5 m3/s. The VOF model is implemented in two solvers: the open source platform OpenFOAM and the commercial CFD package ANSYS Fluent. Validation is undertaken by modelling the scaled physical model of the scheme. Prototype scale simulations of the two flow rates are undertaken, with comparisons between predictions at the two scales being used to establish discrepancies between the two scales. Overall the two solvers predict the prototype flows to be shallower and with higher velocities than those at model scale, but with these scale effects becoming less prominent for increasing flow rates. In the 40 m3/s case the wave structures in the prototype present elongation compared to those at model scale. In the PMF case, in addition to elongation, the wave structures also change in position. Work is currently underway with the modelling of further flow rates in order to investigate the discrepancies between scale and prototype simulations with increased detail and determine limits to minimise impact of scaling

Intermedialität und Filmnarratologie. Intermediale Wechselspiele in DAS LEBEN DER ANDEREN

Die disziplinübergreifende Begriffsvielfalt macht Intermedialität zu einem schwer definierbaren Phänomen in der medienwissenschaftlichen Forschungsarbeit. Da Intermedialität noch nicht als medienübergreifender Bereich gefasst wird, fehlt bislang eine terminologische, konzeptionelle und theoretische Präzisierung (vgl. Rajewsky 2002: 3). Insbesondere die Abgrenzung von anderen Phänomenen wie der Intra- oder Transmedialität ist in der Forschung umstritten und hängt von dem zugrunde gelegten Text- und Medienbegriff ab

Investigating scale effects of a hydraulic physical model with 3D CFD

In the present study, the three-dimensional (3D) Computational Fluid Dynamics (CFD) Volume of Fluid (VOF) method is validated to reproduce hydraulic free surface flows over a labyrinth weir and a spillway for several flow rates using the open source toolbox OpenFOAM 3.0.1 and the commercial CFD package ANSYS Fluent 17.2. The CFD solvers are employed to simulate the 1:25 scale Froude number similarity physical model of the scheme, with validation conducted using experimental observations and measurements. It is found that both solvers are capable of accurately reproducing the velocities and depths measured in the physical model and are also able to capture complex flow features. The models are applied to simulate the prototype hydraulic flows so that scale effects from the physical model can be quantified. Results show the overall decrease in water depth and increase in velocity in the prototype can be up to 15% and 10%, respectively, for the lower flow rates, with scale effects reducing for larger flow rates. The prototype scale simulations also exhibit some variation in the labyrinth weir rating curve when compared to the scaled case; showing lower heads upstream of the crest for the same discharge. As theory would suggest, discrepancies in the rating curve at the two scales are more pronounced for low flow rates