1,720,957 research outputs found
Fluid-structure interactions of anisotropic thin composite materials for application to sail aerodynamics of a yacht in waves
No full textIn recent years technological innovations has allowed large improvements to be made in sail design and construction. Sails and in particular kite-sails have application for sport, ships’ auxiliary propulsion and even power generation. Sails are divided into upwind and downwind sails (Fig.1), where upwind sails operate as lifting surfaces with small angles of attack whereas
traditional downwind sails acted as drag device. New designs of downwind sails have reduced the area of separated flow and increased the lifting behaviour of the sails. In order to capture the lifting behaviour and regions of separation present in both types of sail careful application of computational fluid dynamic analysis tools are required. Solutions of the Reynolds averaged Navier-
Stokes equations (RANSE) are often used as a part of the design process of high performance sailing yachts.The present paper discusses some initial investigations and future guidelines in order to get a more detailed description of the physics involved in sail FSI. Three main fields are therefore covered: the use of CFD in order to accurately capture flow features and a comparison with experimental results; structural modelling; and approach to couplin
A FEM-Matlab code for fluid-structure interaction coupling with application to sail aerodynamics of yachts
No full textA Matlab-FEM code has been developed for deformation analysis of sails as a MSc final project. Sails are modelled as isotropic homogeneous membranes reinforced with cables. The problem, fully non-linear, is resolved by assembling the global stiffness matrix of a mesh of membrane and cable elements in the MatlabTM environment to get an N-equations N-unknowns system. The solution is found with a Quasi- Newton solver. Validation has been performed by comparing numerical results obtained from the developed code with analytical solutions of geometrically simple cases and with experimental data from tests carried out in the DINAV Ship Structures laboratory. A full Fluid Structure Interaction (FSI) analysis of a main sail has been carried out coupling the code with an aerodynamics panel code developed as another MSc final project (Vernengo, 2008). The result is in accordance with the physics of the phenomena and engineering judgment
A FEM-Matlab code for Fluid-Structure interaction coupling with application to sail aerodynamics of yachts
No full textA Matlab-FEM code has been developed for deformation analysis of sails as a MSc final
project. Sails are modelled as isotropic homogeneous membranes reinforced with cables. The problem, fully
non-linear, is resolved by assembling the global stiffness matrix of a mesh of membrane and cable elements
in the MatlabTM environment to get an N-equations N-unknowns system. The solution is found with a Quasi-
Newton solver. Validation has been performed by comparing numerical results obtained from the developed
code with analytical solutions of geometrically simple cases and with experimental data from tests carried
out in the DINAV Ship Structures laboratory. A full Fluid Structure Interaction (FSI) analysis of a main sail
has been carried out coupling the code with an aerodynamics panel code developed as another MSc final
project. The result is in accordance with the physics of the phenomena and engineering
judgment
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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