Scaling Parameters for a Time-Averaged Separation Bubble

1982 ◽  
Vol 104 (2) ◽  
pp. 178-184 ◽  
Author(s):  
A. J. Smits
Keyword(s):  
Bluff Body ◽  
Separation Bubble ◽  
Pressure Coefficient ◽  
Separated Flow ◽  
The Body ◽  
Splitter Plate ◽  
Universal Curve ◽  
Wide Range ◽  
Scaling Parameters ◽  
The Relationship

A splitter plate is placed in the wake of a two-dimensional bluff body. The splitter plate is long enough for the separated flow behind the body to reattach on the splitter plate. The time-averaged properties of this “closed” separation bubble are investigated under a wide range of kinematic conditions. It is found that blockage reduces the base pressure coefficient (Cpb) and the distance to reattachment (l) but the relationship between l and Cpb is not obvious. The pressure distribution in the separated zone, scaled on Cpb and l, can be described by a universal curve. The usefulness of a slotted wall in reducing blockage effects on bluff body flows is shown to be limited in that the wall porosity affects only some properties of the separation bubble.

On the steady separated flow around an inclined flat plate

1997 ◽  
Vol 333 ◽  
pp. 403-413 ◽  
Author(s):  
W. W. H. YEUNG ◽  
G. V. PARKINSON
Keyword(s):  
Flat Plate ◽  
Bluff Body ◽  
Separation Bubble ◽  
Separated Flow ◽  
Leading Edge ◽  
Source Model ◽  
Pressure Distributions ◽  
Wide Range ◽  
Trailing Edges ◽  
Edge Separation

An inviscid analytic model is proposed for the steady separated flow around an inclined flat plate. With the plate normal to the stream, the model reduces to the wake-source model of Parkinson & Jandali originally developed for flow external to a symmetrical two-dimensional bluff body and its wake. At any other inclination, the Kutta condition is satisfied at both leading and trailing edges of the plate, and, in the limit that the angle of attack approaches zero, classical airfoil theory is recovered. A boundary condition is formulated based on some experimental results of Abernathy, but no additional empirical information is required. The predicted pressure distributions on the wetted surface for a wide range of angle attack are found to be in good agreement with experimental data, especially at smaller angles of attack. An extension to include a leading-edge separation bubble is explored and results are satisfactory.

scholarly journals Hyaluronan and the Fascial Frontier

2021 ◽  
Vol 22 (13) ◽  
pp. 6845
Author(s):  
Rebecca L. Pratt
Keyword(s):  
Nerve Fibers ◽  
The Body ◽  
Water Volume ◽  
Cell Behavior ◽  
Connective Tissues ◽  
Wide Range ◽  
The World ◽  
Extracellular Microenvironment ◽  
The Impact ◽  
The Relationship

The buzz about hyaluronan (HA) is real. Whether found in face cream to increase water volume loss and viscoelasticity or injected into the knee to restore the properties of synovial fluid, the impact of HA can be recognized in many disciplines from dermatology to orthopedics. HA is the most abundant polysaccharide of the extracellular matrix of connective tissues. HA can impact cell behavior in specific ways by binding cellular HA receptors, which can influence signals that facilitate cell survival, proliferation, adhesion, as well as migration. Characteristics of HA, such as its abundance in a variety of tissues and its responsiveness to chemical, mechanical and hormonal modifications, has made HA an attractive molecule for a wide range of applications. Despite being discovered over 80 years ago, its properties within the world of fascia have only recently received attention. Our fascial system penetrates and envelopes all organs, muscles, bones and nerve fibers, providing the body with a functional structure and an environment that enables all bodily systems to operate in an integrated manner. Recognized interactions between cells and their HA-rich extracellular microenvironment support the importance of studying the relationship between HA and the body’s fascial system. From fasciacytes to chronic pain, this review aims to highlight the connections between HA and fascial health.

The accumulation of 137Cs by brackish water invertebrates and its relation to the regulation of potassium and sodium

1963 ◽  
Vol 43 (2) ◽  
pp. 541-565 ◽  
Author(s):  
G. W. Bryan
Keyword(s):  
New Media ◽  
Brackish Water ◽  
Sea Water ◽  
Indirect Evidence ◽  
The Body ◽  
Limiting Factor ◽  
Wide Range ◽  
Concentration Factors ◽  
The Relationship ◽  
Potamopyrgus Jenkinsi

The relationship between the ability of brackish water invertebrates to regulate Na and K and the extent to which the radioactive fission product 137Cs can be accumulated has been studied.The brackish water isopod Sphaeroma hookeri and the gastropod Potamopyrgus jenkinsi have been acclimatised to a wide range of sea-water dilutions. Unfed Sphaeroma can survive in sea-water concentrations of 100–2·5%, while Potamopyrgus can live fairly indefinitely in concentrations of 50–0·1%. Measurements of Na and K in the whole animals of both species and in the blood of Sphaeroma have been made. Salt movements are quite rapid and acclimatization to new media is achieved by both species in less than 10 h. Concentration factors for inactive K in particular increase to high values in the more dilute media.Uptake of the isotopes 42K and 137Cs from solution has been examined in both species over a range of sea-water concentrations. All of the body K is exchangeable with 42K and in Sphaeroma exchange of 42K between the blood and tissues is so rapid that the body surface appears to be the limiting factor in the uptake of the isotope. Both species exchange 42K more rapidly in the higher concentrations of sea water and one reason for this may be the existence of an exchange diffusion component of exchange which increases as the salinity of the medium is raised. Indirect evidence suggests that the excretion of 42K in urine is probably not an important factor in exchange.

Some features of steady separated flow from low speed to hypersonic

2008 ◽  
Vol 112 (1128) ◽  
pp. 109-113
Author(s):  
S. L. Gai
Keyword(s):  
Shear Layer ◽  
Bluff Body ◽  
Separated Flow ◽  
Base Flow ◽  
The Body ◽  
Wake Flow ◽  
Recirculating Flow ◽  
Flow Features ◽  
Hypersonic Speeds ◽  
Low Speeds

Steady non-vortex shedding base flow behind a bluff body is considered. Such a flow is characterised by the flow separation at the trailing edge of the body with an emerging shear layer which reattaches on the axis with strong recompression and recirculating flow bounded by the base, the shear layer, and the axis. Steady wake flows behind a bluff body at low speeds have been studied for more than a century (for example, Kirchhoff; Riabouchinsky). Recently, research on steady bluff body wake flow at low speeds has been reviewed and reinterpreted by Roshko. Roshko has also commented on some basic aspects of steady supersonic base flow following on from Chapman and Korst analyses. In the present paper, we examine the steady base flow features both at low speeds and supersonic speeds in the light of Roshko’s model and expand on some further aspects of base flows at supersonic and hypersonic speeds, not covered by Roshko.

Mimi Nichter, Fat talk: What girls and their parents say about dieting. Cambridge, MA: Harvard University Press, 2000. Pp. xi, 263. Hb $22.95.

2002 ◽  
Vol 31 (5) ◽  
pp. 811-815
Author(s):  
Mary Bucholtz
Keyword(s):  
Human Body ◽  
Harvard University ◽  
The Body ◽  
Fat Talk ◽  
Teenage Girls ◽  
Wide Range ◽  
Medical Anthropologist ◽  
The Relationship ◽  
Equal Interest

The relationship between language and the body has become an increasingly prominent area of research within linguistics and related disciplines. Some investigators of this question have examined how facts about the human body are encoded in linguistic structure, while others have explored the use of the body as a communicative resource in interaction. Surprisingly little, however, has been written about the role of language in constructing the body as a social object. In Fat talk, Mimi Nichter, a medical anthropologist, addresses this issue by examining the discourse of dieting among American teenage girls. Although language itself is not the center of the analysis, Nichter draws on a wide range of sociolinguistic research to investigate how the body is constructed through talk – a question that will be of equal interest to scholars of language, culture, and society.

scholarly journals Exosomes and Melatonin: Where Their Destinies Intersect

2021 ◽  
Vol 12 ◽  
Author(s):  
Adriana Alonso Novais ◽  
Luiz Gustavo de Almeida Chuffa ◽  
Débora Aparecida Pires de Campos Zuccari ◽  
Russel J. Reiter
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Cell Communication ◽  
The Body ◽  
Ischemic Brain Injury ◽  
Ischemic Brain ◽  
Complex Process ◽  
Wide Range ◽  
The Relationship ◽  
Robust Evidence

Cell-to-cell communication is a broad and complex process associated with regular stimuli to maintain healthy cell interactions. One of the agents capable of cellular communication is known as an exosome, a subset of extracellular vesicles (EVs) released by the cell membrane. The exosome contains a wide range of functional proteins, mRNAs and miRNAs, which have the potential to interact with healthy or diseased cells in the body. On the other hand, melatonin also acts as a cellular communicator, produced and released by the pineal gland in a circadian way and also, non-circadian melatonin is derived from the mitochondria of all normal cells. In addition to exhibiting antioxidant, anti-inflammatory, anti-tumor and anti-aging activities, melatonin has recently been studied by its influence on exosomes. This review summarizes the relationship between exosomes and melatonin in various pathological processes. There is robust evidence that their combination ameliorates inflammation, ischemia-reperfusion injury, hepatic metabolic disturbance, cancer immunosuppression status, degenerative processes like chronic kidney disease, vascular calcification, ageing, ischemic brain injury, neurodegenerative diseases, obesity, colitis, wound healing and even embryonic development. Association of exosomes and melatonin represent a promising therapeutic tool, capable of interfering with basic molecular processes, such as oxidative stress and the inflammatory cascade, which support many pathophysiological aspects of diseases.

Smell in Eighteenth-Century England

2019 ◽  
Author(s):  
William Tullett
Keyword(s):  
Eighteenth Century ◽  
Scientific Knowledge ◽  
The Body ◽  
The Past ◽  
Wide Range ◽  
History Of ◽  
The Senses ◽  
The Relationship ◽  
Methodological Ground

In England during the period between the 1670s and the 1820s a transformation took place in how smell and the senses were viewed. This book traces that transformation. The role of smell in creating medical and scientific knowledge came under intense scrutiny and the equation of smell with disease was actively questioned. Yet a new interest in smell’s emotive and idiosyncratic dimensions offered odours a new power in the sociable spaces of eighteenth-century England. Using a wide range of sources from diaries, letters, and sanitary records to satirical prints, consumer objects, and magazines, William Tullett traces how individuals and communities perceived the smells around them. From paint and perfume to onions and farts, this book highlights the smells that were good for eighteenth-century writers to think with. In doing so, the study challenges a popular, influential, and often cited narrative. Smell in Eighteenth-Century England is not a tale of the medicalization and deodorization of English olfactory culture. Instead, the book demonstrates that it was a new recognition of smell’s asocial-sociability, its capacity to create atmospheres of uncomfortable intimacy, that transformed the relationship between the senses and society. To trace this shift, the book also breaks new methodological ground. Smell in Eighteenth-Century England makes the case for new ways of thinking about the history of the senses, experience, and the body. Understanding the way past peoples perceived their world involves tracing processes of habituation, sensitization, and attention. These processes help explain which odours entered the archive and why they did so. They force us to recognise that the past was, for those who lived there, not just a place of unmitigated stench

Variations in the relationship between oxygen consumption, body size and summated tissue metabolism in the winkle Littorina littorea

1971 ◽  
Vol 51 (2) ◽  
pp. 315-338 ◽  
Author(s):  
R. C. Newell ◽  
V. I. Pye
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Fractional Power ◽  
The Body ◽  
Acclimation Temperature ◽  
Large Mammals ◽  
Fundamental Relationship ◽  
Wide Range ◽  
Unicellular Organisms ◽  
The Relationship

INTRODUCTIONA considerable amount of data now exists on the relationship between metabolism and body size in a wide range of organisms from bacteria and protozoans through to large mammals. Much of this information has been reviewed by Kleiber (1932, 1947), Brody and Procter (1932), Brody (1945), Zeuthen (1947, 1953), Hemmingsen (1950, i960) and Bertalanffy (1957). In general the metabolism has been shown to be proportional to a fractional power of the body weight thus eggs, the larger metazoan poikilotherms and even homoiotherms is proportional to a constant power of the body weight. This factor has been shown to be 0.751 ± 0.015 by Hemmingsen (i960). Superimposed upon this general relationship are variations according to the weight range of the organisms concerned. Thus both Zeuthen (1953) and Hemmingsen (i960) have shown that the value of the constant b for unicellular organisms is approximately 0.7 (Zeuthen, 1953) or 0.751 (Hemmingsen, 1960), whilst that for small metazoans is 0.95 (Zeuthen, 1953) or 1.0 (Hemmingsen, 1960). Finally, the slope of the line relating the metabolism to body size in larger metazoans is 075 (Zeuthen, 1953) or 0.751 (Hemmingsen, 1960). That is, the value for b — 1 in equation (2) is likely to be between -0.3 and -0.249 in unicellular organisms; 0 and -0.05 in small metazoans and approximately -0.249 in larger metazoans.Despite this apparently fundamental relationship between metabolism and body size, there are many instances where for a particular species the relationship may not apply. Indeed in some species the metabolism may vary in its relationship to body weight according to conditions such as salinity, shore level, experimental temperature and acclimation temperature.

Scaling of the Wall Pressure Field Around Surface-Mounted Pyramids and Other Bluff Bodies

2007 ◽  
Vol 129 (9) ◽  
pp. 1147-1156 ◽  
Author(s):  
Robert Martinuzzi ◽  
Mazen AbuOmar ◽  
Eric Savory
Keyword(s):  
Boundary Layer ◽  
Layer Thickness ◽  
Boundary Layer Thickness ◽  
Bluff Body ◽  
Pressure Field ◽  
Ground Plane ◽  
Pressure Coefficient ◽  
Flow Region ◽  
Surface Flow ◽  
The Body

The turbulent flow around square-based, surface-mounted pyramids, of height h, in thin and thick boundary layers was experimentally investigated. The influence of apex angle ζ and angle of attack α was ascertained from mean surface flow patterns and ground plane pressure measurements taken at a Reynolds number of 3.3×104 based on h. For both boundary layer flows, it was found that the normalized ground plane pressure distributions in the wakes of all the pyramids for all angles of attack may be scaled using an attachment length (Xa′) measured from the upstream origin of the separated shear layer to the near-wake attachment point on the ground plane. It was also shown that this scaling is applicable to data reported in the literature for other bluff body shapes, namely, cubes, cones, and hemispheres. The ground plane pressure coefficient distributions in the upstream separated flow region, for all the shapes and angles of attack examined, were found to collapse onto two curves by scaling their streamwise location using a length scale (Xu), which is a function of the frontal projected width of the body (w′) and the height of the body. These two curves were for cases where δ∕h<1 (“thin” boundary layer) or δ∕h≥1 (“thick” boundary layer), where δ is the oncoming boundary layer thickness. Further work is required to provide a more detailed statement on the influence of boundary layer thickness (or state) on the upstream pressure field scaling.

Numerical calculation of separated flow past square and rectangular cylinders using panel technique

2006 ◽  
Vol 110 (1106) ◽  
pp. 249-256
Author(s):  
A. Roy ◽  
G. Bandyopadhyay
Keyword(s):  
Separated Flow ◽  
The Body ◽  
Experimental Investigations ◽  
Surface Pressure Distribution ◽  
Collocation Points ◽  
Flow Past ◽  
Wide Range ◽  
Rectangular Cylinders ◽  
Low Speed Wind Tunnel ◽  
Potential Flow Model

AbstractIn the present investigation, a potential flow model based on panel method has been developed for calculation of two dimensional separated flows past square and rectangular cylinders. Free vortex lines are assumed to emanate from the points of separation that converge downstream of the body. The converged wake shape is iteratively obtained by integrating the velocity vectors at the collocation points. For solving separated flow past square and rectangular cylinders, four different versions of the solver have been developed for a wide range of incidence, namely, for zero, low, moderate and high angles of incidence. For validation of computed results, experimental investigations have been carried out in a low speed wind tunnel to obtain the surface pressure distribution on square cylinder and rectangular cylinder over a range of angles of incidence. Comparison is reasonably good.

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