1,721,022 research outputs found
Ralf Deiterding H2-O2 detonation structures in smooth pipe bends Numerical Simulation of Transient Detonation Structures in H2-O2 Mixtures in Smooth Pipe Bends
No full textAccidental internal detonation waves are a common threat to the pipeline systems of petrochemica
International Workshop on Fluid-Structure Interaction. Theory, Numerics and Applications
No full text... Fluid-Structure Interaction Simulation of Viscoplastic and Fracturing Thin- Shells Subjected to Underwater Shock Loading Ralf Deiterding, Fehmi Cirak, ..
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
Dynamically adaptive Simulation Of Regular . . .
No full textNumerical simulations can be the key to the thorough understanding of the multi-dimensional nature of transient detonation waves. But the accurate approximation of realistic detonations is extremely demanding, because a wide range of different scales needs to be resolved. This paper describes an entire solution strategy that is based on a generic implementation of a dynamically adaptive mesh refinement strategy which utilises logically rectangular meshes. The hydrodynamic upwind scheme and the treatment of the sti# non-equilibrium reaction terms are sketched. We explain the design of AMROC, a freely available dimension-independent block-structured mesh adaptation framework for time-explicit Cartesian finite volume methods on distributed memory machines. Briefly, we discuss the employed locality-preserving rigorous domain decomposition technique and its parallel performance. The ghost fluid approach is integrated into the refinement algorithm to allow for embedded non-Cartesian boundaries represented implicitly by additional level-set variables. Large-scale simulations of unstable detonation structures of hydrogen-oxygen detonations run on recent Linux-Beowulf-clusters demonstrate the efficiency of the described techniques in practice. In particular, computations of regular cellular structures in two and three space dimensions and their development under transient conditions, i.e. under di#raction and for propagation through a 60 degree pipe bend are presented. The enormous e#ective resolutions go beyond previously published results and allow new thermo-hydrodynamic insight
Research Statement
No full textMy primary research topic is the development of numerical methods for the approximation of solutions to the nonlinear partial differential equations that arise in computational fluid mechanics (CFD). I am particular interested in efficient and robust solution methods for flows in evolving domains that are directly applicable to real-world problems. The main tools of my research are Cartesian schemes with embedded boundary capability, block-structured hierarchical multilevel refinement and the idea of implicit geometry representation via level set functions. I want to utilize these principles to construct highly efficient numerical methods in all flow regimes and to combine the implementations in a unified, fully parallelized software framework. The resulting infrastructure would enable wellresolved simulations of very difficult flow problems, like multiphase or free-surface flows with fluidstructure interaction.
- …
