968 research outputs found
Linear global stability of a confined plume
No full textAbstractA linear stability analysis is performed for a plume flow inside a cylinder of aspect ratio 1. The configuration is identical to that used by Lopez and Marques (2013) for their direct numerical simulation study. It is found that the first bifurcation, which leads to a periodic axisymmetric flow state, is accurately predicted by linear analysis: both the critical Rayleigh number and the global frequency are consistent with the reported DNS results. It is further shown that pressure feedback drives the global mode, rather than absolute instability
Lutz Weltmann Correspondence Collection. 1923-1969 Bulk dates: 1930-1955
No full textThe Lutz Weltmann Correspondence Collection largely holds professional correspondence from others to Lutz Weltmann, a critic, publisher, author and teacher. Such correspondence often references various literary projects of Weltmann's or of the correspondents. One letter by him includes a brief curriculum vitae.Lutz Weltmann was born on February 15, 1901 in Elbing (now Elblag, Poland). He attended the universities of Berlin and Freiburg, receiving his doctorate in philosophy from the University of Freiburg in 1924. From 1924-1933 he was the theater and literature critic of Rudolf Mosse newspapers in Berlin, including the Berliner Volkszeitung, but also contributed as a freelance writer for the Frankfurter General-Anzeiger and the Kölnische Zeitung, among others. From 1927-1933 he was co-editor of the monthly Die Literatur (later titled Das literarische Echo). In 1934 he authored some articles for the Jüdisches Jahrbuch on Spinoza and in 1936 he lectured on Samuel Cooper for the Jüdischer Kulturbund and produced Jizchok Leib Perez's Die goldene Kette for the Kulturbund's theater. In the course of his work he came to know many other authors, critics and others in the field of literature and theater.After emigrating to England in 1939, he served in the British Pioneer Corps from 1940-1943. The following year he earned his teaching diploma in London in 1944 and then taught at various schools in Kent, London and Essex. He also wrote from England for West German newspapers after the war. During this time he was assistant editor of the series The Goethe Year 1749-1949- Das Goethe-Jahr 1749-1949, celebrating the bi-centenary of the birth of Goethe, and wrote a book on Kasimir Edschmid. He also wrote three unpublished works on Christopher Fry, T.S. Eliot, and on Shakespeare.All letters on the list "Briefe on Lutz Weltmann" not previously digitized were consolidated into this collectionProcesseddigitize
"Y'all come and have fun": discovering a New Jersey country and western music scene in a box of postcards
No full textSeveral years ago, Rutgers University's Special Collections and University Archives was given a checkbox containing fifty-six postcards advertising country and western music shows at venues around New Jersey. The postcards, primarily from the 1960s, promoted shows featuring Grand Ole Opry stars like Wanda Jackson, Hank Thompson, and Elton Britt. Preliminary research revealed that the postcards touted performances by regional and local musicians, as well. A closer look at the cards began to expose how a small, hyper-local ephemeral collection could bring to light and contribute to a larger history; in this case, a once thriving but little explored New Jersey country and western music scene. The research that forms this article focuses on one venue, the Copa Club in the city of Secaucus, and its owners, brothers and musicians Shorty and Smokey Warren, as a specific case study. This collection of postcards, like so much ephemeral material in archives, could have remained undervalued and under-researched. In this case, a close consideration set forth a journey that included research in local archives and interviews with scene participants. As a result, this article explores the past of an important musical genre that evolved along with social changes in the United States. This piece contributes to the scholarship around uses and value of ephemera, as well as scholarship that continues to challenge the southern origin story of country music and examine vital locales of country music outside the South.Peer reviewe
Cabin in the Pines: Albert Music Hall and constructions of a Pine Barrens musical tradition
No full textAlbert Music Hall is an outpost of bluegrass, folk, and country music in the New Jersey Pine Barrens, offering hours of live music every Saturday night. It has formally been in existence since the 1970s under the auspices of the Pinelands Cultural Society, but it traces its roots back to the 1950s, when brothers Joe and George Albert started hosting informal musical gatherings at their Pines fox hunting cabin, known in the area as the Homeplace. What started as locals playing old-time and country music at a rustic cabin deep in the woods has evolved into a more formal venue that features musicians from around New Jersey and beyond. Albert Music Hall has persisted as an island of an older, more rural, and isolated Pines in an industrialized, urbanized state. Through an examination of the language, material culture, and music of the venue, this paper considers questions and constructions of authenticity in relation to notions of what a true Pine Barrens musical experience might be for Albert Music Hall audiences and musicians.Peer reviewe
Going against the archival grain: case studies of pop culture archives of a music scene, regional zines, and local beer
No full textPopular culture collecting in academic special collections and archives is sometimes still viewed within the institution as a challenge to traditional collection development, which has tended to emphasize the mainstream and enshrine privilege and hegemonic structures. This is especially the case when the cultures and media emphasized in such collecting might be categorized as being counter-cultural, DIY, or somehow ‘other.’ This article consists of three case studies that emphasize recently developed popular culture-based collections at Rutgers University’s Special Collections and University Archives that focus on voices and communities outside archival norms of collecting: the New Brunswick Music Scene Archive, the New Jersey Regional Zine Collection, and the New Jersey Beer Collection. An emphasis on how faculty and staff have developed these collections by working with participants and creators outside mainstream popular culture leads to examples of how faculty and staff have engaged in critical pedagogy and outreach, particularly among students. Woven throughout are examples of challenges faculty and staff have faced around institutional acceptance, inclusivity, and cultural sensitivities along with work to overcome the challenges. The article concludes by considering future popular culture collection-building endeavors and engagement among students and community members.Peer reviewe
Artificial eigenmodes in truncated flow domains
No full textInternational audienceWhenever linear eigenmodes of open flows are computed on a numerical domain that is truncated in the streamwise direction, artificial boundary conditions may give rise to spurious pressure signals that are capable of providing unwanted perturbation feedback to upstream locations. The manifestation of such feedback in the eigenmode spectrum is analysed here for two simple configurations. First, explicitly prescribed feedback in a Ginzburg-Landau model is shown to produce a spurious eigenmode branch, named the 'arc branch', that strongly resembles a characteristic family of eigenmodes typically present in open shear flow calculations. Second, corresponding mode branches in the global spectrum of an incompressible parallel jet in a truncated domain are examined. It is demonstrated that these eigenmodes of the numerical model depend on the presence of spurious forcing of a local k + instability wave at the inflow, caused by pressure signals that appear to be generated at the outflow. Multiple local k + branches result in multiple global eigenmode branches. For the particular boundary treatment chosen here, the strength of the pressure feedback from the outflow towards the inflow boundary is found to decay with the cube of the numerical domain length. It is concluded that arc-branch eigenmodes are artifacts of domain truncation, with limited value for physical analysis. It is demonstrated, for the example of a non-parallel jet, how spurious feedback may be reduced by an absorbing layer near the outflow boundary
Modes globaux non-lineaires et generation de son dans les jets chauds.
No full textThe objective of this thesis is twofold: firstly, to study the dynamics inherent in the near field of axisymmetric hot jets by direct numerical simulation, and describe the synchronized oscillations in terms of the theory of nonlinear global modes. On the other hand, characterize the aero-acoustic far field generated by the synchronized oscillations of the near field, also by direct numerical simulation, and identify the physical nature of the aero-acoustic sources in the jet. Thus it is established that the intrinsic synchronized oscillations are observed in the simulations have all the characteristics of a nonlinear global mode, governed by a stationary front located at the upstream edge of an absolutely unstable environment. A linear stability analysis reveals that a jet becomes absolutely unstable hot enough near the nozzle, through the destabilizing effect of the baroclinic torque. The emergence of self-sustained oscillations and their frequency, observed numerically, precisely follow the predictions derived from theoretical criteria. The numerical results are in good agreement with experiments from the literature. The global mode of a hot jet emits a dipole sound field and an analysis of the Lighthill equation shows that this radiation is due to fluctuations in entropy, in contrast to an isothermal jet forced, which sources linked quadrupole the Reynolds stresses are dominant.L'objectif de cette thèse est double : d'une part, étudier la dynamique intrinsèque dans le champ proche des jets chauds axisymétriques par simulation numérique directe, et décrire ces oscillations synchronisées sous l'angle de la théorie des modes globaux non-linéaires. D'autre part, caractériser le champ lointain aéro-acoustique généré par les oscillations synchronisées du champ proche, également par simulation numérique directe, et identifier la nature physique des sources aéro-acoustiques dans le jet. Ainsi il est établi que les oscillations synchronisées intrinsèques que l'on observe dans les simulations possèdent toutes les caractéristiques d'un mode global non-linéaire, régi par un front stationnaire situé au bord amont d'un milieu absolument instable. Une analyse d'instabilité linéaire révèle qu'un jet suffisament chaud devient absolument instable près de la buse, grâce à l'effet déstabilisant du couple barocline. L'apparition des oscillations auto-entretenues ainsi que leur fréquence, observées numériquement, suivent précisement les prédictions déduites des critères théoriques. Les résultats numériques sont en bon accord avec les expériences tirées de la littérature. Le mode global d'un jet chaud émet un champ sonore dipolaire; une analyse de l'équation de Lighthill révèle que ce rayonnement est dû aux fluctuations d'entropie, à la différence d'un jet isotherme forcé, pour lequel les sources quadripolaires liées au tenseur de Reynolds sont dominantes
Structures cohérentes dans des écoulements turbulents
No full textCette thèse s'intéresse à un formalisme récent, le formalisme résolvent, pour proposer une modélisation à ordre faible d'écoulements turbulents. Cette approche linéaire a un intérêt académique en permettant une meilleure compréhension des mécanismes concernés, mais aussi pour l'industrie en permettant des cycles de recherche et développement moins coûteux en calcul. Les travaux réalisés incluent une approche résolvante enrichie du tenseur de Reynolds appliquée dans le cas de l'écoulement canal, et une étude en profondeur du comportement d'un jet turbulent en rotation. Purement numérique, cette contribution s'appuie sur la méthode éléments finis et le formalisme Reynolds-Averaged-Navier-Stokes. Parmi les résultats obtenus, on notera la découverte de nouveaux comportements des jets à basse fréquence ainsi que leur interprétation. Certains de ces effets ne sont pas à portée des méthodes précédemment employées.This thesis is focused on a recent formalism called resolvent formalism, in order to put forward a low rank model of turbulent flows. This linear approach is of interest from an academical perspective as a way to better understand the mechanisms at play, as well as from an industry perspective by allowing for cheaper development cycles. Works detailed in this thesis include a resolvent approach enriched by the Reynolds stress tensor applied in the channel flow case, and an in depth study of a swirling turbulent jet. Based on purely numerical endeavours, this contribution is making ample use of finite element methods and Reynolds-Averaged--Navier-Stokes formalism. Amongst the obtained results, new jet behaviours at low frequency were brought to light as well as interpreted. Some of these effects are simply out of reach more traditional linear analysis methods
Author Disambiguation in PubMed: Evidence on the Precision and Recall of Author-ity among NIH-Funded Scientists.
No full textWe examined the usefulness (precision) and completeness (recall) of the Author-ity author disambiguation for PubMed articles by associating articles with scientists funded by the National Institutes of Health (NIH). In doing so, we exploited established unique identifiers-Principal Investigator (PI) IDs-that the NIH assigns to funded scientists. Analyzing a set of 36,987 NIH scientists who received their first R01 grant between 1985 and 2009, we identified 355,921 articles appearing in PubMed that would allow us to evaluate the precision and recall of the Author-ity disambiguation. We found that Author-ity identified the NIH scientists with 99.51% precision across the articles. It had a corresponding recall of 99.64%. Precision and recall, moreover, appeared stable across common and uncommon last names, across ethnic backgrounds, and across levels of scientist productivity
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