1,721,363 research outputs found
Laudatio anlässlich der Enthüllung einer Gedenktafel am Gebäude Theaterstraße 16 am 10. Juni 2016
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A Simplified Model of the Wave Generation Due to Train-Tunnel Entry
No full textThe compression wave generated when a high-speed train cnters a tunnel
at Mach numbers smaller than 0.4 can be described in good approximation by a linear theory of an inviscid fluid. The wave equation for the acoustic potential becomes the governing equation. lt is solved by a three dimensional boundary elcment method in time domain which forces a vanishing normal component of the velocity at the tunnel wall. lt is assumed that the elements arc compact in time. This leads to a
linear equation in which a special matrix-vector multiplication has to be evaluatcd for every time-step. The aim is to crcate a fast method which sets as few constraints on the geometry as possible but nevertheless gives an accurate description of the wave propagation. ln a first stcp the elements are assumed to bc rectangles and an infinitely thin cylindric tube of finite length is taken as the geometry of the tunnel. The train is modeled by a single moving mass source of monopole type. lt defines
a semi-infinitc body whose shape slightly changes when entcring the tunnel. The results of this simple model along with the comparison with analytical solutions and experimental data are shown and discussed
New Results in Numerical und Experimental Fluid Mechanics XIII
No full textThis book offers timely insights into research on numerical and experimental fluid mechanics and aerodynamics, mainly for (but not limited to) aerospace applications. It reports on findings by members of the STAB (German Aerospace Aerodynamics Association) and DGLR (German Society for Aeronautics and Astronautics) and covers both nationally and EC-funded projects. Continuing on the tradition of the previous volumes, the book highlights innovative solutions, promoting translation from fundamental research to industrial applications. It addresses academics and professionals in the field of aeronautics, astronautics, ground transportation, and energy alike
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
Aerodynamic Loads Induced by Passing Trains on Track Side Objects
No full textThe aerodynamic loads on a sphere induced by the head pressure pulse of a passing train are calculated using potential flow theory. The results are compared with experimental data which were measured in a moving model rig. The loads were calculated using two different theoretical approaches. They show good agreement with the experimentally obtained results even though in the theoretical model the geometry of the train and the embankment is simplified
New Results in Numerical and Experimental Fluid Mechanics XII
No full textThis book gathers contributions to the 21st biannual symposium of the German Aerospace Aerodynamics Association (STAB) and the German Society for Aeronautics and Astronautics (DGLR). The individual chapters reflect ongoing research conducted by the STAB members in the field of numerical and experimental fluid mechanics and aerodynamics, mainly for (but not limited to) aerospace applications, and cover both nationally and EC-funded projects. Special emphasis is given to collaborative research projects conducted by German scientists and engineers from universities, research-establishments and industries. By addressing a number of cutting-edge applications, together with the relevant physical and mathematics fundamentals, the book provides readers with a comprehensive overview of the current research work in the field. The book’s primary emphasis is on aerodynamic research in aeronautics and astronautics, and in ground transportation and energy as well
Development of Artificial Neural Networks with Integrated Conditional Random Fields Capable of Predicting Non-linear Dynamics of the Flow Around Cylinders
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