scholarly journals Numerical Investigation of Shock Wave Diffraction over a Sphere Placed in a Shock Tube

2016 ◽  
Vol 2016 ◽  
pp. 1-5
Author(s):  
Sergey Martyushov ◽  
Ozer Igra ◽  
Tov Elperin
Keyword(s):  
Shock Tube ◽  
Drag Coefficient ◽  
Flow Model ◽  
The Body ◽  
Shock Wave Diffraction ◽  
Present Scheme ◽  
The Past ◽  
Steady Flow Condition ◽  
Experimental Findings ◽  
Good Agreement

For evaluating the motion of a solid body in a gaseous medium, one has to know the drag constant of the body. It is therefore not surprising that this subject was extensively investigated in the past. While accurate knowledge is available for the drag coefficient of a sphere in a steady flow condition, the case where the flow is time dependent is still under investigation. In the present work the drag coefficient of a sphere placed in a shock tube is evaluated numerically. For checking the validity of the used flow model and its numerical solution, the present numerical results are compared with available experimental findings. The good agreement between present simulations and experimental findings allows usage of the present scheme in nonstationary flows.

Simulation of Sphere’s Motion Induced by Shock Waves

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Dan Igra ◽  
Ozer Igra ◽  
Lazhar Houas ◽  
Georges Jourdan
Keyword(s):  
Shock Waves ◽  
Drag Coefficient ◽  
Drag Force ◽  
Stationary Flow ◽  
Experimental Results ◽  
Experimental Findings ◽  
Sphere Drag ◽  
Simulation Scheme ◽  
Good Agreement

Simulations of experimental results appearing in Jourdan et al. (2007, “Drag Coefficient of a Sphere in a Non-Stationary Flow: New Results,”Proc. R. Soc. London, Ser. A, 463, pp. 3323–3345) regarding acceleration of a sphere by the postshock flow were conducted in order to find the contribution of the various parameters affecting the sphere drag force. Based on the good agreement found between present simulations and experimental findings, it is concluded that the proposed simulation scheme could safely be used for evaluating the sphere’s motion in the postshock flow.

Pressure-fluctuation measurements on an oscillating circular cylinder

1979 ◽  
Vol 91 (4) ◽  
pp. 661-677 ◽  
Author(s):  
P. W. Bearman ◽  
I. G. Currie
Keyword(s):  
Circular Cylinder ◽  
Flow Model ◽  
Free Stream ◽  
Pressure Fluctuations ◽  
The Body ◽  
The Mean ◽  
Simple Potential ◽  
Lock In ◽  
Potential Flow Model ◽  
Good Agreement

Measurements are presented of the fluctuating pressure recorded at a point 90° from the mean position of the forward stagnation point on a circular cylinder oscillating in a water flow. The aspect ratio of the cylinder was 9·5 and the turbulence level in the free-stream was 5·5%. The cylinder Reynolds number was 2·4 × 104 and the cylinder was forced to oscillate transverse to the main flow at amplitudes up to 1·33 cylinder diameters. The reduced velocity was varied over the range 3–18 and the experiments spanned the vortex-shedding lock-in range. Measurements of phase difference between pressure and displacement show that the maximum out-of-phase lift force occurs at an amplitude of about half a diameter. Good agreement is found between measurements on forced and freely oscillating cylinders. A simple potential-flow model gives reasonable predictions of the pressure fluctuations at the body frequency and at twice the body frequency at reduced velocities away from lock-in.

NUMERICAL MODEL TO SIMULATE THE EROSION ON THE SLOPE DUE TO OVERTOPPING

2010 ◽  
Vol 13 (3) ◽  
pp. 78-87
Author(s):  
Hoai Cong Huynh
Keyword(s):  
Numerical Model ◽  
Flow Model ◽  
Bed Load ◽  
Experiment Data ◽  
Step Method ◽  
Morphological Model ◽  
Load Transport ◽  
Bed Load Transport ◽  
The Finite Difference Method ◽  
Good Agreement

The numerical model is developed consisting of a 1D flow model and the morphological model to simulate the erosion due to the water overtopping. The step method is applied to solve the water surface on the slope and the finite difference method of the modified Lax Scheme is applied for bed change equation. The Meyer-Peter and Muller formulae is used to determine the bed load transport rate. The model is calibrated and verified based on the data in experiment. It is found that the computed results and experiment data are good agreement.

Derrida on Pornography: Putting (It) Up for Sale

Derrida Today ◽  
2013 ◽  
Vol 6 (1) ◽  
pp. 97-114 ◽  
Author(s):  
Christopher Morris
Keyword(s):  
Cultural Studies ◽  
English Translation ◽  
The Body ◽  
The Past ◽  
French Original ◽  
Definition Of ◽  
Critical Discourses ◽  
Academic Debate

Over the past thirty years, academic debate over pornography in the discourses of feminism and cultural studies has foundered on questions of the performative and of the word's definition. In the polylogue of Droit de regards, pornography is defined as la mise en vente that is taking place in the act of exegesis in progress. (Wills's idiomatic English translation includes an ‘it’ that is absent in the French original). The definition in Droit de regards alludes to the word's etymology (writing by or about prostitutes) but leaves the referent of the ‘sale’ suspended. Pornography as la mise en vente boldly restates the necessary iterability of the sign and anticipates two of Derrida's late arguments: that there is no ‘the’ body and that performatives may be powerless. Deriving a definition of pornography from a truncated etymology exemplifies the prosthesis of origin and challenges other critical discourses to explain how pornography can be understood as anything more than ‘putting (it) up for sale’.

Receptions of the Past: Commemoration, Racism, Desire

Somatechnics ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 288-303
Author(s):  
Michael Connors Jackman
Keyword(s):  
Critical Point ◽  
Social Relations ◽  
White Privilege ◽  
Body Politic ◽  
The Body ◽  
Race And Racism ◽  
Lesbian And Gay ◽  
The Past ◽  
History Of

This article investigates the ways in which the work of The Body Politic (TBP), the first major lesbian and gay newspaper in Canada, comes to be commemorated in queer publics and how it figures in the memories of those who were involved in producing the paper. In revisiting a critical point in the history of TBP from 1985 when controversy erupted over race and racism within the editorial collective, this discussion considers the role of memory in the reproduction of whiteness and in the rupture of standard narratives about the past. As the controversy continues to haunt contemporary queer activism in Canada, the productive work of memory must be considered an essential aspect of how, when and for what reasons the work of TBP comes to be commemorated. By revisiting the events of 1985 and by sifting through interviews with individuals who contributed to the work of TBP, this article complicates the narrative of TBP as a bluntly racist endeavour whilst questioning the white privilege and racially-charged demands that undergird its commemoration. The work of producing and preserving queer history is a vital means of challenging the intentional and strategic erasure of queer existence, but those who engage in such efforts must remain attentive to the unequal terrain of social relations within which remembering forms its objects.

Body and Desire

2018 ◽  
Author(s):  
Raphael A. Cadenhead
Keyword(s):  
Full Range ◽  
The Body ◽  
Gregory Of Nyssa ◽  
The Past ◽  
Ethical Discourse ◽  
Sex And Sexuality ◽  
Diachronic Analysis

Although the reception of the Eastern father Gregory of Nyssa has varied over the centuries, the past few decades have witnessed a profound awakening of interest in his thought, particularly in relation to the contentious issues of gender, sex, and sexuality. The Body and Desire sets out to retrieve the full range of Gregory’s thinking on the challenges of the ascetic life through a diachronic analysis of his oeuvre. Exploring his understanding of the importance of bodily and spiritual maturation in the practices of contemplation and virtue, Raphael Cadenhead recovers the vital relevance of this vision of transformation for contemporary ethical discourse.

Stress management: Corpus-based insights into vernacular interpretations of stress

2014 ◽  
Vol 10 (1) ◽  
pp. 81-93
Author(s):  
Laurel Smith Stvan
Keyword(s):  
Traumatic Stress ◽  
American English ◽  
Physical Symptom ◽  
The Body ◽  
Post Traumatic Stress ◽  
The Past ◽  
Academic Texts ◽  
Naturally Occurring ◽  
Post Traumatic ◽  
Semantic Shift

Examination of the term stress in naturally occurring vernacular prose provides evidence of three separate senses being conflated. A corpus analysis of 818 instances of stress from non-academic texts in the Corpus of Contemporary American English (COCA) and the Corpus of American Discourses on Health (CADOH) shows a negative prosody for stress, which is portrayed variously as a source outside the body, a physical symptom within the body and an emotional state. The data show that contemporary speakers intermingle the three senses, making more difficult a discussion between doctors and patients of ways to ‘reduce stress’, when stress might be interpreted as a stressor, a symptom, or state of anxiety. This conflation of senses reinforces the impression that stress is pervasive and increasing. In addition, a semantic shift is also refining a new sense for stress, as post-traumatic stress develops as a specific subtype of emotional stress whose use has increased in circulation in the past 20 years.

Numerical Studies on Trapped-Vortex Concepts for Stable Combustion

1998 ◽  
Vol 120 (1) ◽  
pp. 60-68 ◽  
Author(s):  
V. R. Katta ◽  
W. M. Roquemore
Keyword(s):  
Drag Coefficient ◽  
Reacting Flow ◽  
Flow Conditions ◽  
Third Order ◽  
Cold Flow ◽  
Flow Simulations ◽  
Numerical Studies ◽  
Dynamic Flows ◽  
Experimental Findings ◽  
Trapped Vortex

Spatially locked vortices in the cavities of a combustor aid in stabilizing the flames. On the other hand, these stationary vortices also restrict the entrainment of the main air into the cavity. For obtaining good performance characteristics in a trapped-vortex combustor, a sufficient amount of fuel and air must be injected directly into the cavity. This paper describes a numerical investigation performed to understand better the entrainment and residence-time characteristics of cavity flows for different cavity and spindle sizes. A third-order-accurate time-dependent Computational Fluid Dynamics with Chemistry (CFDC) code was used for simulating the dynamic flows associated with forebody-spindle-disk geometry. It was found from the nonreacting flow simulations that the drag coefficient decreases with cavity length and that an optimum size exists for achieving a minimum value. These observations support the earlier experimental findings of Little and Whipkey (1979). At the optimum disk location, the vortices inside the cavity and behind the disk are spatially locked. It was also found that for cavity sizes slightly larger than the optimum, even though the vortices are spatially locked, the drag coefficient increases significantly. Entrainment of the main flow was observed to be greater into the smaller-than-optimum cavities. The reacting-flow calculations indicate that the dynamic vortices developed inside the cavity with the injection of fuel and air do not shed, even though the cavity size was determined based on cold-flow conditions.

scholarly journals Calculating the optimal hematocrit under the constraint of constant cardiac power

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michal Sitina ◽  
Heiko Stark ◽  
Stefan Schuster
Keyword(s):  
Blood Flow ◽  
High Performance ◽  
Animal Species ◽  
Normal Values ◽  
Mechanical Load ◽  
The Body ◽  
Trade Off ◽  
Cardiac Power ◽  
Optimal Value ◽  
Good Agreement

AbstractIn humans and higher animals, a trade-off between sufficiently high erythrocyte concentrations to bind oxygen and sufficiently low blood viscosity to allow rapid blood flow has been achieved during evolution. Optimal hematocrit theory has been successful in predicting hematocrit (HCT) values of about 0.3–0.5, in very good agreement with the normal values observed for humans and many animal species. However, according to those calculations, the optimal value should be independent of the mechanical load of the body. This is in contradiction to the exertional increase in HCT observed in some animals called natural blood dopers and to the illegal practice of blood boosting in high-performance sports. Here, we present a novel calculation to predict the optimal HCT value under the constraint of constant cardiac power and compare it to the optimal value obtained for constant driving pressure. We show that the optimal HCT under constant power ranges from 0.5 to 0.7, in agreement with observed values in natural blood dopers at exertion. We use this result to explain the tendency to better exertional performance at an increased HCT.

scholarly journals Epithelial Protein Lost in Neoplasm, EPLIN, the Cellular and Molecular Prospects in Cancers

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1038
Author(s):  
Jianyuan Zeng ◽  
Wen G. Jiang ◽  
Andrew J. Sanders
Keyword(s):  
The Body ◽  
Early Years ◽  
Actin Binding ◽  
Cell Cycle Gene ◽  
Lim Domain ◽  
The Past ◽  
Concise Review ◽  
Cancerous Cell ◽  
Cytoskeletal Dynamics ◽  
In Cells

Epithelial Protein Lost In Neoplasm (EPLIN), also known as LIMA1 (LIM Domain And Actin Binding 1), was first discovered as a protein differentially expressed in normal and cancerous cell lines. It is now known to be key to the progression and metastasis of certain solid tumours. Despite a slow pace in understanding the biological role in cells and body systems, as well as its clinical implications in the early years since its discovery, recent years have witnessed a rapid progress in understanding the mechanisms of this protein in cells, diseases and indeed the body. EPLIN has drawn more attention over the past few years with its roles expanding from cell migration and cytoskeletal dynamics, to cell cycle, gene regulation, angiogenesis/lymphangiogenesis and lipid metabolism. This concise review summarises and discusses the recent progress in understanding EPLIN in biological processes and its implications in cancer.

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