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Facilitating advanced spectral element simulations of wall-bounded flows
No full textThe overarching aim of this thesis is to enable accurate simulations of high-Reynolds-number wall-bounded flows, representative of those encountered in realistic engineering applications. Achieving this goal requires progress on several fronts, ranging from methodological developments to computational considerations and the application of simulations to relevant flow configurations. First, advances are made in numerical techniques for scale-resolving simulations of wall-bounded turbulence. New methods are introduced that allow turbulent boundary layers to be simulated efficiently at arbitrarily high Reynolds numbers and sustained over long physical times. In addition, existing turbulence inflow generation approaches are assessed with particular emphasis on their suitability for aeroacoustic predictions, where a physically consistent representation of turbulent structures is essential. Second, the ability of scale-resolving simulations to exploit emerging computing architectures is investigated. In particular, the sensitivity of such simulations to reduced-precision arithmetic, a feature increasingly common in modern high-performance computing hardware, is systematically evaluated. This provides insights into the accuracy–efficiency trade-offs that can be expected as computational platforms evolve. Finally, the methods are applied to canonical but engineering-relevant test cases that combine fundamental physical interest with practical significance. Direct numerical simulations are carried out for flow over the Boeing speed bump and for a drone rotor at moderate Reynolds numbers. For the Boeing speed bump, a detailed analysis of boundary-layer dynamics is performed, providing new insights into the interaction between geometry-induced pressure gradients and turbulent structures. The drone rotor simulations, in turn, represent a first step toward applying scale-resolving methods to realistic aerodynamic configurations where both performance and noise are of interest. Overall, the contributions of this thesis span algorithmic development, computational assessment, and application to canonical test cases, thereby laying the foundation for scale-resolving simulations of wall-bounded turbulence at conditions directly relevant to engineering design.Det övergripande målet med denna avhandling är att möjliggöra noggranna simuleringar av väggbundna strömmar vid höga Reynolds-tal, representativa för de förhållanden som återfinns i verkliga ingenjörstillämpningar. För att uppnådetta krävs framsteg på flera områden, från metodutveckling till datoranpassning och tillämpning på relevanta strömningsfall. För det första presenteras nya numeriska metoder för skalanupplösande simuleringar av väggbunden turbulens. Dessa metoder gör det möjligt att på etteffektivt sätt simulera turbulenta gränsskikt vid godtyckligt höga Reynolds-tal och att upprätthålla simuleringarna under långa tidsperioder. Vidare utvärderas befintliga inflödesmetoder för turbulens med särskilt fokus på deras lämplighet för aeroakustiska prediktioner, där en fysiskt konsekvent representation av turbulenta strukturer är avgörande. För det andra undersöks skalanupplösande simuleringars förmåga att utnyttjanya beräkningsarkitekturer. I synnerhet analyseras känsligheten hos dessasimuleringar för reducerad numerisk precision, en egenskap som blir allt vanligare i modern högprestandaberäkning. Detta ger viktiga insikter i av vägningen mellan noggrannhet och beräkningseffektivitet vid framtida beräkningsplattformar. Slutligen tillämpas metoderna på kanoniska men ingenjörsrelevanta fall som kombinerar fundamentalt fysikaliskt intresse med praktisk betydelse. Direkta numeriska simuleringar genomförs för strömning över en Boeing speed bump samt för en drönarrotor vid måttliga Reynolds-tal. För Boeing speed bump analyseras gränsskiktets fysik i detalj, vilket ger nya insikter om samspelet mellan geometriinducerade tryckgradienter och turbulenta strukturer. Simuleringarnaav drönarrotorn utgör i sin tur ett första steg mot att tillämpa skalanupplösande metoder på realistiska aerodynamiska konfigurationer där både prestanda ochbuller är av intresse. Sammanfattningsvis spänner avhandlingens bidrag från metodutveckling och datorarkitektoniska utvärderingar till tillämpning på kanoniska testfall. Därmed läggs en grund för skalanupplösande simuleringar av väggbunden turbulens under förhållanden som är direkt relevanta för ingenjörsmässig design.QC 250930</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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