Analysis of LES and 1D Hot-Wire Data to Determine Actively Generated Main Flow Turbulence in a Film Cooling Test Rig

2021 ◽  
Author(s):  
Lukas Fischer ◽  
Michael Straußwald ◽  
Michael Pfitzner

Abstract A vortex generator was incorporated into a wind tunnel to investigate more realistic inflow conditions for film cooling test rigs. The flow field signals are sampled numerically by probes in LES simulations and experimentally by using 1D hot-wire measurements to determine turbulence quantities. The LES shows that the turbulence is anisotropic which cannot be detected by the 1D hot-wire. Furthermore, the integral length scale which shall provide insight into the sizes of the turbulent eddies is determined using two approaches. The first uses the one probe at two times correlation method and could be evaluated from the numerical and experimental probes. The second correlation method exploits the spatial resolution in the LES domain by using the two probes at one time approach. Both methods show combustor-like turbulence length scales downstream of the vortex generator if the triple decomposition is applied onto the velocity signal.

2018 ◽  
Vol 18 (2) ◽  
pp. 127-148 ◽  
Author(s):  
Alexandru Brad

This article is about the practice of territorial governance emerging at the junction of European Union-sanctioned ideals and Romanian development-planning traditions. On the one hand, the European agenda emphasises a smart, inclusive, sustainable model of economic growth. However, the persisting centralised workings of the Romanian state significantly alters the scope of regional interventions. As such, while core cities grew their economies swiftly, peripheral places were left in an unrelenting stagnation. My first aim is to provide a theoretical ground for a practicecentred approach to understanding territorial governance. Second, by drawing on Romania’s regional policy context as an example, I give an insight into how practices of partnership and competition fare in a context of ongoing territorial polarisation. I conclude by emphasising the need for a regional redistributive policy mechanism, one which should enable and assist non-core areas to access capacities for defining and implementing development projects.


2020 ◽  
Vol 151 (1) ◽  
pp. 96-126
Author(s):  
Kathryn Crim
Keyword(s):  
The One ◽  

Karl Marx’s comments on silk manufacture in “The Working Day” chapter of Capital, volume 1, demonstrate how “quality”—usually associated with “use value”—has been mobilized by capital to naturalize industrialized labor. Putting his insight into conversation with a recent multimedia poetic project, Jen Bervin’s Silk Poems (2016–17), this essay examines the homology between, on the one hand, poetry’s avowed task of fitting form to content and, on the other, the ideology of labor that fits specific bodies to certain materials and tasks.


1991 ◽  
Vol 15 (2) ◽  
pp. 123-138
Author(s):  
Joachim Biskup ◽  
Bernhard Convent

In this paper the relationship between dependency theory and first-order logic is explored in order to show how relational chase procedures (i.e., algorithms to decide inference problems for dependencies) can be interpreted as clever implementations of well known refutation procedures of first-order logic with resolution and paramodulation. On the one hand this alternative interpretation provides a deeper insight into the theoretical foundations of chase procedures, whereas on the other hand it makes available an already well established theory with a great amount of known results and techniques to be used for further investigations of the inference problem for dependencies. Our presentation is a detailed and careful elaboration of an idea formerly outlined by Grant and Jacobs which up to now seems to be disregarded by the database community although it definitely deserves more attention.


The freeze-etching technique must be improved if structures at the molecular size level are to be seen. The limitations of the technique are discussed here together with the progress made in alleviating them. The vitrification of living specimens is limited by the fact that very high freezing rates are needed. The critical freezing rate can be lowered on the one hand by the introduction of antifreeze agents, on the other hand by the application of high hydrostatic pressure. The fracture process may cause structural distortions in the fracture face of the frozen specimen. The ‘double-replica’ method allows one to evaluate such artefacts and provides an insight into the way that membranes split. During etching there exists the danger of contaminating the fracture faces with condensable gases. Because of specimen temperatures below —110 °C, special care has to be taken in eliminating water vapour from the high vacuum. An improvement in coating freeze-etched specimens has resulted from the application of electron guns for evaporation of the highest melting-point metals. If heat transfer from gun to specimen is reduced to a minimum, Pt, Ir, Ta, W and C can be used for shadow casting. Best results are obtained with Pt-C and Ta-W . With the help of decoration effects Pt-C shadow castings give the most information about the fine structural details of the specimen.


1995 ◽  
Vol 38 (11) ◽  
pp. 2117-2125 ◽  
Author(s):  
V.P. Lebedev ◽  
V.V. Lemanov ◽  
S.Ya. Misyura ◽  
V.I. Terekhov

Author(s):  
Fathima Banu Raza ◽  
Anand Kumar

The o-rings in ball retained overdentures deteriorate with time and need replacement to restore the retentive quality. We evaluated retrospectively the mechanical properties of o-rings after 3 years in function in one and two-piece implant-supported overdentures. The o-rings were retrieved from one-piece (Myriad snap, Equinox-Straumann, 3.3 x 13mm) and two-piece (Neo Biotech, 3.3 x 13mm) implant-supported overdenture patients. A total of 16 pairs of matrices were tested for wear, type of damage and elasticity using Pin on Disc method, USB Digital Camera in 30x zoom and Universal Tensile Machine respectively. The statistical analysis for independent groups were done with the Mann-Whitney U test. Assessment of used O-rings showed 84% more wear in the two-piece system with an abrasive type of damage while 46% wear in the one-piece system with a compressive type of damage. The o-rings in one-piece system showed increase in elongation and maximum displacement to 2% and 7% respectively, while two-piece system showed decrease in elongation and maximum displacement by 13% and 6% respectively. In one-piece system, the loss of retention was more with slow wear rate and in two-piece system, the wear resistance of O-rings decreased due to increased stiffness. Further studies to evaluate the changes in O-ring with increased sample size and at interval 1 year will pave way for insight into the progressive changes in the mechanical properties of an O-ring.


2021 ◽  
Vol 13 (1) ◽  
pp. 129-152
Author(s):  
Jon Stewart

In his Lectures on the Philosophy of Religion, Hegel argues that the development of the religions of the world leads up to and culminates in Christianity, which is the one true religion. One key element which separates Christianity from the other religions, according to Hegel, concerns the issue of alienation. He argues that the previous religions all contain some form of alienation, which can be found in their conceptions of the divine. In this paper, I wish to examine Hegel’s view that Christianity alone overcomes religious alienation. What is it that makes Christianity so special in this regard? This is a particularly important issue given that the question of alienation is so central in the post-Hegelian thinkers such as Feuerbach, Bauer, and Marx, who all insist that, far from overcoming alienation, Christianity is guilty of causing it. I wish to argue that this issue provides new insight into the old criticism of Hegel as a thinker of abstraction.


2012 ◽  
Vol 56 (4) ◽  
pp. 998-1021 ◽  
Author(s):  
Miguel ángel Jiménez-Crespo ◽  
Maribel Tercedor

Localization is increasingly making its way into translation training programs at university level. However, there is still a scarce amount of empirical research addressing issues such as defining localization in relation to translation, what localization competence entails or how to best incorporate intercultural differences between digital genres, text types and conventions, among other aspects. In this paper, we propose a foundation for the study of localization competence based upon previous research on translation competence. This project was developed following an empirical corpus-based contrastive study of student translations (learner corpus), combined with data from a comparable corpus made up of an original Spanish corpus and a Spanish localized corpus. The objective of the study is to identify differences in production between digital texts localized by students and professionals on the one hand, and original texts on the other. This contrastive study allows us to gain insight into how localization competence interrelates with the superordinate concept of translation competence, thus shedding light on which aspects need to be addressed during localization training in university translation programs.


Author(s):  
Aaron F. Shinn ◽  
S. Pratap Vanka

Large Eddy Simulations were performed to study the effect of a micro-ramp on an inclined turbulent jet interacting with a cross-flow in a film-cooling configuration. The micro-ramp vortex generator is placed downstream of the film-cooling jet. Changes in vortex structure and film-cooling effectiveness are evaluated and the genesis of the counter-rotating vortex pair in the jet is discussed. Results are reported with the jet modeled using a plenum/pipe configuration. This configuration was designed based on previous wind tunnel experiments at NASA Glenn Research Center, and the present results are meant to supplement those experiments. It is found that the micro-ramp improves film-cooling effectiveness by generating near-wall counter-rotating vortices which help entrain coolant from the jet and transport it to the surface. The pair of vortices generated by the micro-ramp are of opposite sense to the vortex pair embedded in the jet.


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