1,720,959 research outputs found
Extended self-similarity in numerical simulations of three-dimensional anisotropic turbulence
No full textUsing a code based on the lattice Boltzmann equation, we have performed numerical simulations of a turbulent shear flow. We investigate the scaling behavior of the structure functions in presence of anisotropic homogeneous turbulence, and we show that although extended self-similarity does not hold when strong shear effects are present, a more generalized scaling law can still be defined. © 1996 The American Physical Society
On the intermittent energy transfer at viscous scales in turbulent flows.
No full textIn this letter we present numerical and experimental results on the scaling properties of velocity turbulent fields in the range of scales where viscous effects are acting. A generalized version of extended self-similarity capable of describing scaling laws of the velocity structure functions down to the smallest resolvable scales is introduced. Our findings suggest the absence of any sharp viscous cut-off in the intermittent transfer of energy. © 1995 IOP Publishing Ltd
Scaling property of turbulent flows
No full textWe discuss a possible theoretical interpretation of the self-scaling property of turbulent flows [extended self similarity (ESS)]. Our interpretation predicts that, even in cases when ESS is not observed, a generalized self-scaling must be observed. This prediction is checked on a number of laboratory experiments and direct numerical simulations. © 1996 The American Physical Society
Self-scaling properties of velocity circulation in shear flows
No full textWe investigate the scaling properties of the velocity circulation of a turbulent shear flow. We evaluate, using extended self-similarity, the circulation scaling exponents both at maximum and minimum shear regions. We show that the anomalous component of the velocity circulation and the anomalous component of the velocity structure functions are equal. © 1997 The American Physical Society
Generalized scaling in fully developed turbulence
No full textIn this paper we report numerical and experimental results on the scaling properties of the velocity turbulent fields in several flows. The limits of a new form of scaling, named Extended Self-Similarity (ESS), are discussed. We show that, when a mean shear is absent, the self-scaling exponents are universal and they do not depend on the specific flow (3D homogeneous turbulence, thermal convection, MHD). In contrast, ESS is not observed when a strong shear is present. We propose a generalized version of self-scaling which extends down to the smallest resolvable scales even in cases where ESS is not present. This new scaling is checked in several laboratory and numerical experiments. A possible theoretical interpretation is also proposed. A synthetic turbulent signal having most of the properties of a real one has been generated. Copyright © 1996 Elsevier Science B.V. All rights reserved
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
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