1,720,960 research outputs found
A Novel Scheme for Two-Dimensional Compressible Flow on Moving Meshes with Large Deformations
No full textCompressible Fluid-Flow ALE Formulation on Changing Topology Meshes for Aeroelastic Simulations
No full textThe analysis of unsteady fluid flows on moving domains is a very complex task, that may be often tackled using domain remeshing techniques. In the present paper a novel mesh movement strategy is presented. It is based on the blending of simple local edge-swapping with mesh deformation by means of the elastic analogy. To deal with mesh topology changes an extension of the classical Arbitary Lagrangian-Eulerian formulation of the fluid flow equations is developed. In this way the use of interpolations of fluid fields between old and new grid is avoided. Furthermore, this extension allows the easy implementation of high order time integration schemes. Preliminary two dimensional numerical simulations are presented to demonstrate the correctness of the present approach. They shows how this approach guarantees a high quality of the grid without resorting to remeshing, resulting in a very efficient solver useful for the analysis of Fluid-Structure Interaction problems, even for the cases which requires large mesh deformations or changes in the domain topology
Integrated Aeroservoelastic Analysis of Induced Strain Rotor Blades
No full textThis paper presents an application of an original formulation for the characterization of generally anisotropic, non-homogeneous beam sections including induced-strain devices (in this case piezo-electric patches) to the aeroservoelastic analysis and optimization of actively twisted helicopter rotor blades. The induced-strain inclusions can have arbitrary shape and orthotropy. The beam section characterization is based on a semi-analytical approach to the analysis of the beam, where the section is modeled as a 2-D FE model. The linear and angular strains of the beam, the free warping of the section and the electric potential are solved in terms of unit internal forces, moments and electric charge density on the electrodes under appropriate boundary conditions to provide the elastic and electro-static solution of the compliance problem. This solution yields the 6 × 6 generalized elastic and inertia properties, the 6 × N generalized piezo-electric properties and the N × N dielectric properties of a piezo-electric beam section characterized by N independent piezo-electric patches. These properties, and detailed information about the strain and stress state inside the beam section for each span-wise location are used to synthesize noteworthy geometric, mechanical, aeroelastic and piezo-electric properties to be used in the definition of the objective function and the constraints of an aeroservoelastic optimization problem. The piezo-electric blade section characterization is detailed; the optimization procedure is illustrated, and relevant results are presented and discussed in view of indications arising from simplified models based on the monocoque theory
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
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