An investigation of free surface hydraulic structures using large eddy simulation and computational fluid dynamics

University of Technology, Sydney. Faculty of Engineering and Information Technology.The work presented in this dissertation is essentially a thesis in three distinct parts (single fluid validation, two fluid validation and data analysis) rather than the established approach for the development of a novel computational fluid dynamics solver. First, the progression is a traditional one, in which an existing technique was applied to a new area and subsequently extended. Second, from detailed analysis of the large volume of data generated in the validation process, a number of insights were gained into the flow features of the prototypes investigated that extended beyond a traditional validation study and discovered a number of new physical phenomena. Previous researchers have used monotonically integrated large eddy simulation (MILES) methods to investigate a range of flows including turbulent decay in rotary valve engines and rocket body dynamics. MLES methods have the distinct advantage over standard LES simulation techniques in that they promise to provide similar levels of detail and accuracy but at a fraction of the computational cost. However, to the author’s knowledge these techniques have not been applied to the prototype problem of this thesis: cylinders in cross flow without and with free surfaces. Hence the raison d’étre of this thesis: to apply a faster yet equally accurate CFD method to a free surface problem via a validated single fluid investigation. Specifically, the progression was to first validate the method against a single right square cylinder in cross flow without a free surface and then to extend the method to a right circular cylinder in cross flow with a free surface. With the right square cylinder without free surface the research focussed on the extensively studied configuration of a two dimensional square cylinder at a Reynolds number of 22 × 10³. Despite the agreement of the validation parameters with published data, detailed examination of the flow field revealed inconsistencies in the modelled results. In particular the power spectrum decay of the data appear too “easy” to obtain, indicating possible flaws in the theoretical basis, while correlation data apparently supports a conclusion that the previous assumption of four diameters domain width is too narrow to provide an uncorrelated flow region. The free surface physics of the circular cylinder model was captured with the volume of fluid method and was applied to Reynolds number flows based on cylinder diameter of between 27 × 10³ and 54 × 10³. These flows, at the provided grid resolution, push the lower boundary of what can be called MILES, yet interpretations of the results indicates that the model is accurately capturing the physics of the flows

An 8000-year multi-proxy peat-based palaeoclimate record from Newfoundland: Evidence of coherent changes in bog surface wetness and ocean circulation

Energy carried by warm tropical water, transported via the Atlantic Meridional Overturning Circulation (AMOC), plays a vital role in regulating the climate of regions bordering the North Atlantic Ocean. Previous phases of elevated freshwater input to areas of North Atlantic Deep Water (NADW) production in the early to mid-Holocene have been linked with slow-downs in the AMOC and changes in regional climate. Newfoundland’s proximity in the North Atlantic region to the confluence of the Gulf Stream and the Labrador Current and to an area of NADW production in the Labrador Sea makes it an ideal testing ground to investigate the influence of past fluctuations in ocean circulation on terrestrial ecosystems. We use multi-proxy peat-based records from the east coast of Newfoundland to derive a proxy-climate signal for the last 8000 years, which we have compared with changes in ocean circulation. Prominent shifts towards near-surface bog water table levels, reflecting cooler/wetter climatic conditions, are evident in the early-mid Holocene c. 7830, 7500, 7220 and 6600 cal. BP with minor changes occurring c. 6340, and 6110 cal. BP. These events are coherent with evidence of meltwater injections into the N. Atlantic and of reduced NADW production. More recent increases in bog surface wetness in the mid-late Holocene c. 4290 and c. 2610 cal. BP are also consistent with reported periods of reduced NADW production. Coherence between the bog-derived palaeoclimate record developed from Newfoundland and evidence of fluctuations in ocean current strength is apparent in the early mid-Holocene

Is ARR 2015 a watershed moment for how we manage hydrologic data?

© 2015, Engineers Australia. All rights reserved. As network speeds have increased, online delivery of data has the potential to revolutionise the hydrologic industry not only in Australia but worldwide, for example the recent ARR Revision Projects on regional flood frequency estimation and the interaction of coastal and riverine flooding. There are a number of distinct advantages to centralising data stores, namely: quality control that can ensure practitioners are all using the same consistent data set as well as revision control in case changes are required in the future. These, and other, ARR projects, although small scale, have proved that the limitations are not technical but rather cultural, namely they fear of confidentiality when accessing services from remote third party servers as well as the institutionalised culture of downloading and archiving copies of data and software. Centralised data management confronts the established dogma of software licensing in that the concept of paying a single license fee for a particular version or data snapshot is, essentially, eliminated. We believe that this will be replaced with an alternate hybrid organisational structure similar to an open source software project combined with a not-for-profit business that would be run by the industry for the industry. This paper presents a brief overview of the already eliminated technical issues and, more importantly, challenges the hydrologic community to critically evaluate their view of data and software ownership, hydrologic engineering workflows and the direction of collaboration in a data centric workplace

Diversité du peuplement ligneux d’une forêt dense en zone sub-humide : Cas de la forêt de Sakété dans le sud-Bénin en Afrique de l’Ouest

Cette étude réalisée en zone sub-humide présente les caractéristiques du peuplement ligneux de la forêt classée de Sakété située au sud-Bénin. La méthode de collecte des données sur la végétation a combiné la méthode d’inventaire floristique et celle dite de relevés itinérants. Le cortège floristique du peuplement ligneux actuel de la forêt classée de Sakété est constitué de 123 espèces réparties en 95 genres et 41 familles. Les Euphorbiaceae, les Leguminosae (16 espèces chacune) et les Rubiaceae (13 espèces) sont les mieux représentées. Trois types de formations végétales ont été définis : une forêt dense humide semi-décidue à Trilepiseum madagascariensis et Dichapetalum crassifolium, une forêt inondable à Anthonotha crassifolia et Symphonia globulifera et une forêt marécageuse à Anthostema aubryanum et Alchornea cordifolia. La richesse spécifique varie de 10 à 22 espèces ; les indices de diversité de Shannon et l’équitabilité de Pielou varient respectivement de 2,4 à 3,8 bits et de 0,5 à 0,8. La densité du peuplement (80 à 200 individus/ha) est relativement faible et témoigne d’une exploitation anarchique. La surface terrière du peuplement a varié de 12,9 à 20,2 m²/ha. La végétation de cet écosystème forestier, encore riche en espèces, présente cependant des signes de dégradation.Mots clés: Inventaire floristique, forêt classée, végétation, gestion durabl

The Psychodynamic Diagnostic Manual – 2nd edition (PDM-2)

For decades many clinicians, especially psychodynamic and humanistic therapists, have resisted thinking about their patients in terms of categorical diagnoses. In the current era, they find themselves having to choose between reluctantly “accepting” the DSM diagnostic labels, “denying” them, or developing alternatives more consistent with the dimensional, inferential, contextual, biopsychosocial diagnostic formulations characteristic of psychoanalytic and humanistic approaches. The Psychodynamic Diagnostic Manual (PDM) reflects an effort to articulate a psychodynamically oriented diagnosis that bridges the gap between clinical complexity and the need for empirical and methodological validity. In this paper the authors (the steering committee of the PDM-2) describe the process of construction of the PDM-1 and discuss changes proposed for implementation in PDM-2

Vertical zonation of testate amoebae in the Elatia Mires, northern Greece : palaeoecological evidence for a wetland response to recent climate change or autogenic processes?

The Elatia Mires of northern Greece are unique ecosystems of high conservation value. The mires are climatically marginal and may be sensitive to changing hydroclimate, while northern Greece has experienced a significant increase in aridity since the late twentieth century. To investigate the impact of recent climatic change on the hydrology of the mires, the palaeoecological record was investigated from three near-surface monoliths extracted from two sites. Testate amoebae were analysed as sensitive indicators of hydrology. Results were interpreted using transfer function models to provide quantitative reconstructions of changing water table depth and pH. AMS radiocarbon dates and 210Pb suggest the peats were deposited within the last c. 50 years, but do not allow a secure chronology to be established. Results from all three profiles show a distinct shift towards a more xerophilic community particularly noted by increases in Euglypha species. Transfer function results infer a distinct lowering of water tables in this period. A hydrological response to recent climate change is a tenable hypothesis to explain this change; however other possible explanations include selective test decay, vertical zonation of living amoebae, ombrotrophication and local hydrological change. It is suggested that a peatland response to climatic change is the most probable hypothesis, showing the sensitivity of marginal peatlands to recent climatic change

Bioactive Properties and Phenolic Composition of Wood-Aged Beers: Influence of Oak Origin and the Use of Pale and Dark Malts

Ageing beer in contact with wood is a common technological procedure that has been used for centuries to improve colour, structure, and certain flavours. Herein, the impact of the addition of French and American oak wood to two beer styles, pale and dark, on beer phenolic composition (total phenolics, total flavonoids, and HPLC-DAD) and bioactivity (FRAP, DPPH, anti-inflammatory activity in RAW 264.7, and antiproliferative in Caco-2 cells) was assessed. Thirteen phenolics were quantified with values according to previous reports. Dark malt resulted in higher values of total phenolics, to which m-hydroxybenzoic, syringic, p-coumaric acids, and xanthohumol contributed considerably; the exception was (+)-catechin and salicylic acid, which were found to be higher in pale beers. American oak significantly increased 3,4-dihydroxyphenylacetic, vanillic, and syringic acids up to roughly 3, 2, and 10 times, respectively, when compared with French wood. FRAP and DPPH values varied between pale and dark beers, with a less pronounced effect after wood addition. All samples presented considerable cellular antioxidant and anti-inflammatory as well as antiproliferative activity, but differences were found only for the antiproliferative activity, which was higher for the dark beers, which reached about 70% inhibition. Overall, the influence of malts was more pronounced than that of wood, in the studied conditions, highlighting the overwhelming impact of malts on the bioactivity of beer

Bacille Calmette-Guérin (BCG) vaccine and potential cross-protection against SARS-CoV-2 infection - Assumptions, knowns, unknowns and need for developing an accurate scientific evidence base

After a century of controversies on its usefulness in protection against TB, underlying mechanisms of action, and benefits in various groups and geographical areas, the BCG vaccine is yet again a focus of global attention- this time due to the global COVID-19 pandemic caused by the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Recent studies have shown that human CD4+ and CD8+ T-cells primed with a BCG-derived peptide developed high reactivity to its corresponding SARS-CoV-2-derived peptide. Furthermore, BCG vaccine has been shown to substantially increase interferon-gamma (IFN-g) production and its effects on CD4+ T-cells and these non-specific immune responses through adjuvant effect could be harnessed as cross protection against severe forms of COVID-19.The completion of ongoing BGG trials is important as they may shed light on the mechanisms underlying BCG-mediated immunity and could lead to improved efficacy, increased tolerance of treatment, and identification of other ways of combining BCG with other immunotherapies