1,720,954 research outputs found
Numerical simulation of the aerodynamics and acoustics of a wall-mounted spoiler
No full textA steep descent with deployed spoilers is a potential noise abatement procedure. This study investigates noise sources solely due to spoilers by examining a spoiler mounted on a flat plate. An experimental database consisting of aerodynamic loads, microphone measurements, on-surface pressure distributions, hot wire anemometry, and particle image velocimetry is presented. Numerical simulations, performed using a lattice Boltzmann solver ProLB, are validated against these experimental data. While the geometry is relatively simple, this is still a challenging case to accurately predict numerically, particularly the boundary-layer separation bubble that occurs upstream of the spoiler. The flow is characterized by an arch-type broadband wake without any coherent vortex shedding. There is a horseshoe vortex that originates upstream of the spoiler and wraps around both sides of the spoiler. Inboard of the horseshoe vortex there are a pair of ground vortices with the opposite sign vorticity to the horseshoe vortex. A combination of band-filtered on-surface pressures and three-dimensional numerical beamforming was used to determine the noise sources. As well as the broadband bluff body wake and the horseshoe vortex, the beamforming showed that the ground edge vortices and the spoiler side edges were the dominant acoustic sources
Scaling laws for aerodynamic loads and acoustics of wall-mounted plates at different deflection angles
No full textInclined flat plates mounted on horizontal surfaces have applications in the aerospace, renewable energy and automotive sectors. While previous studies have examined how aspect ratio and proximity to a mounting surface affect aerodynamic loads on a plate, a systematic investigation of scaling laws for aerodynamic loads and acoustics is lacking. This paper establishes scaling relationships for the aerodynamic loads and the flow-induced noise generated by a wall-mounted flat plate inclined to the flow. Wind tunnel experiments were conducted using a Kevlar-walled test section, with a wall-mounted flat plate deflected between 10◦ and 90◦ across various Reynolds numbers. A correction method based on the bluff body blockage corrections of Maskell and calibrated using open test section wind tunnel data is presented in this work to account for solid and wake blockage effects in the Kevlar test section experiments. For aerodynamic loads, the normalised normal force coefficient collapses when scaled with projected frontal area, converging to a fixed value of the drag coefficient at 90◦. This provides a simple predictive methodology for the aerodynamic loads with maximum errors of ΔCD = 0.073 and ΔCL = 0.081. The scaling law presented in this work is unique for wall-mounted flat plates and differs for flat plates in freestream. Aeroacoustic analysis reveals broadband noise without coherent vortex shedding. The noise scales approximately, but not perfectly, with the sixth power of velocity. The slight variations in the value of the velocity exponent at different deflection angles highlight that it does not simply scale as a compact dipole but other effects are present, including non-compactness and edge scattering effects. The acoustic scaling with projected area exhibits different behaviour at low and high deflection angles. At low deflection angles, the plate is partially immersed in the boundary layer, reducing the acoustic intensity variation with deflection angle. At higher deflection angles (> 30◦), the acoustic intensity scaled with the projected area to a power of 1.2 again indicating additional sources besides the scaling of pure compact dipole sources
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
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