bluuebunny/crossref_metadata_2025 huggingface dataset:
Seeing Vanbrugh and Hawksmoor
Authors: Cast David
Published: April 2006

Vanbrugh and Hawksmoor have suffered perhaps more harshly than most architects from the fancies of taste. Certain of their buildings are discussed here: the Writing School and the Goose-pie House, which, characteristically, have been demolished; and two others, Grimsthorpe Castle and St. Mary Woolnoth, which have at moments been threatened with demolition. But this article is concerned less with history than with what might be called the critical situation of Hawksmoor and Vanbrugh, which it examines under two aspects. The first is a tradition of concerns-some contemporary, some of which seem only to have surfaced in the work of later commentators-that seem necessary for an understanding of what Vanbrugh and Hawksmoor were doing. These include: the notion of "effect"; Pope's distinction between "rules" and "the reasoning of the eye"; the 18th-century record of Gothic architecture; Hobbes's account of the active mind; the resurgence of patriotism of England; and, at the end, the idea of historical meditation that Johnson alluded to in his notes on topographical poetry. The second aspect is the growing body of formal and informal criticism of architecture in England in the 18th century, most of which-even aside from Lord Burlington's-found the work of Hawksmoor and Vanbrugh puzzling or wrong. It is suggested that this tradition of criticism is of service. For what it refers to is the originality and the indecorousness of what Vanbrugh and Hawksmoor did. Originality now is unoriginal; indecorousness is perhaps impossible. Within the tradition Vanbrugh and Hawksmoor knew, these qualities were significant and new, and yet-as the record shows-they were a matter of confusion for many.
Remembrances of the Home Insurance Building
Authors: Turak Theodore
Published: April 2006

The years 1984 and 1985 constitute the centennial of one of the 19th century's most significant structures, the Home Insurance Building in Chicago. Ground for the Home Insurance was broken 1 May 1884 and it received its first tenants in the fall of 1885. Since that time, some have hailed it as the world's first true skyscraper; others have seen it as unspectacular and merely transitional. This paper will explore the opinions of the men who were most intimately connected with its construction: the architect, William Le Baron Jenney; his partner, William Mundie; the building's fireproofing contractor, Peter B. Wight; and one of Jenney's competitors for the commission, Frederick Baumann. I have based this article on documents, some of them recently discovered, that were written at widely different times. When brought together, however, they seem to create a dialog between these men, the results of which cast some light on the circumstances surrounding the design and erection of the Home Insurance Building. Moreover, these documents give us valuable insight into the human aspects of what has heretofore been held as a purely technical problem in the history of architecture.
The First Medici Palace
Authors: Saalman Howard , Mattox Philip
Published: April 2006

Cosimo de' Medici's great house on the Via Larga in Florence, begun in the mid-1440s, was the model of Early Renaissance palace architecture. By the time he moved into it, however, sometime before 1458, Cosimo's life had nearly run its course. Most of his years had been spent in the house of his father, the casa vecchia of the Medici, also on the Via Larga. Possibly at the same time as the construction of the new palace, this first Medici palace underwent a transformation that united the main house and flanking buildings behind one vast façade. This article seeks to ascertain the precise nature and location of the old Medici complex on the Via Larga through examination of the visual and documentary evidence of the casa vecchia and all adjoining properties. An inventory of the house made in 1418 suggests a tentative reconstruction of the interior of the old palace, while comparison with other 14th-century houses may warrant certain assumptions about its external appearance. It will be seen that a striking similarity exists between the 1418 inventory of parts of the first Medici palace and the order of the palace begun by Cosimo de' Medici in the 1440s. As was usual in Early Renaissance architecture, the components and arrangement of an earlier house became the point of departure for the program and layout of a new house.
A New Plan of the Cloister and Rampart of Saint-Etienne, Toulouse
Authors: Horste Kathryn
Published: April 2006

A newly discovered plan of the medieval rampart of Toulouse in the vicinity of the Cathedral of Saint-Etienne includes a detailed plan of the Romanesque cloister of the Cathedral, which was destroyed in the early years after the Revolution. The plan, an official copy of an original drawn in 1780 by Jacques Paschal Virebent, indicates that the architecture of the cloister was similar to that which has been proposed for the contemporary Cluniac cloister of La Daurade in Toulouse, the model for which was the cloister of the nearby Abbey of Moissac, completed in 1100. Within the limited body of evidence that can be brought to bear on a reconstruction of the sculptural program of the cloister, the new plan is the most concrete and credible document. A much-cited 19th-century lithograph of the cloister and claims made about the provenance of its sculpture by the antiquarian Alexandre Du Mège are, on the other hand, shown to be highly untrustworthy. The plan also provides evidence for the original course of the Gallo-Roman city wall and of the medieval modifications to it in the vicinity of the Cathedral and Gateway of Saint-Etienne.
Zoning and "Zeitgeist": The Skyscraper City in the 1920s
Authors: Willis Carol
Published: April 2006

Originally instituted simply as restrictive legislation with no aesthetic aims, in the 1920s zoning became the principal inspiration behind a new style in skyscraper design and a new vision of the modern metropolis. After reviewing the specific influence and importance of the New York City zoning law of 1916, the country's landmark legislation, the article examines the commentary on zoning in the architectural press, focusing in particular on the predictions of the law's impact on the morphology of the future city. Previous scholarship has treated the history of zoning in a negative light and has ignored its relationship to visionary ideas. Yet in the many prophecies of a rationalized skyscraper city that were advanced in the 1920s, we can preview the birth of what many architects and critics of the period excitedly pronounced a new era in American architecture and urbanism.
Municipal Parks and City Planning: Frederick Law Olmsted's Buffalo Park and Parkway System
Authors: Kowsky Francis R.
Published: April 2006

For three decades beginning in 1868, Frederick Law Olmsted and his partners and successors created for Buffalo, the second largest city in New York State, a series of parks and parkways that attracted national and international attention. Olmsted's work for Buffalo occupied a prominent place in his influential career as park planner and urban reformer. In Buffalo, Olmsted and his partner Calvert Vaux implemented a comprehensive series of parks and parkways that pioneered the concept of the metropolitan recreational system. Initially conceived between 1868 and 1870 and substantially constructed by 1876, Olmsted and Vaux's Buffalo park system carefully modified the city's original plan, framed in 1804 by Joseph Ellicott, and introduced progressive design features inspired by the example of the Second Empire in Paris.
The Chapel of S. Felice in Padua as "Gesamtkunstwerk"
Authors: Edwards Mary D.
Published: April 2006

The Chapel of S. Felice in the southern transept of the Basilica of S. Antonio in Padua was commissioned by the condottiere, Bonifazio de' Lupi in 1372. Its principal designers were the architect and sculptor Andriolo de' Santi, and the painter Altichiero. In transforming the pre-existing transept of the Basilica into the chapel, Andriolo solved many problems. He converted a large, unfocused space into an intimate one; he regularized an irregular ground plan; he resolved a potential conflict of longitudinal and lateral axes; and he established the means to focus the viewer's attention on both the altar and the tombs of the chapel's patron and his kinsmen. Altichiero tailored his frescoes to Andriolo's architectural container to make of the chapel a compelling gesamtkunstwerk. He accentuated the powerful cross axes by pictorial means; he established cogent iconographical and formal interrelationships between the frescoes and other components of the chapel; and, finally, he integrated sunlight and compass orientations with the decorative scheme. By these means the artists fashioned a Trecento masterpiece which heralds the chapels of the Baroque era in which all three media are synchronized with one another and with their setting.
The German Rundbogenstil and Reflections on the American Round-Arched Style
Authors: Curran Kathleen
Published: April 2006

This article investigates the German Rundbogenstil and its influence on the American "round-arched style." A stylistic and theoretical phenomenon of the 19th century, the German Rundbogenstil held both a specific and a generic meaning: as a contemporary building style and as a term for historical round-arched architecture. In modern scholarship, the Rundbogenstil has come to denote any round-arched building with Romanesque or Italianate features designed by certain early to mid-19th-century German architects. A general contextual analysis of the complex nature of the 19th-century round-arched styles or "tendencies" in Germany helps to define more precisely the Rundbogenstil. Following a theoretical and stylistic examination of major monuments in Karlsruhe, Munich, and Berlin, the present paper outlines the salient characteristics of the Rundbogenstil and its influence in America in the hands of certain central European emigrant architects in New York and two major mid-19th-century American architects. The fundamental theoretical change which the style underwent in the United States in both of these groups warrants a distinct label-the American "round-arched style."
Architects Read Vitruvius: Renaissance Interpretations of the Atrium of the Ancient House
Authors: Pellecchia Linda
Published: April 2006

From Alberti to Palladio, Renaissance architects and architectural theorists struggled to interpret the description of the ancient Roman house set forth by Vitruvius in De architectura. The debate concerning the form and function of the atrium-the most essential room of the ancient domus-provides the basis for a case study of the process by which Renaissance readers transformed words into images to visualize the parts of the ancient house. Lacking archaeological remains of the Roman domus, architects were forced to rely on written sources. Their zeal to understand led them to appropriate the philological tools of humanists, explicating Vitruvius's words by reading other texts. The result was a wealth of contradictory information, which permitted, indeed encouraged, a variety of reconstructions of the atrium. During a period of about one hundred years-from the 1450s to the 1560s-the Vitruvian atrium underwent numerous incarnations: a courtyard, a vestibule, a domed octagonal sala, a three-aisled basilica. Despite their often imaginative and probing research, none of the Renaissance architects ever conceived of the atrium exactly as it was in antiquity. Their [mis]interpretations, nonetheless, had an impact on contemporary design. In a period in which patrons wanted houses inspired by antiquity, the reconstructed atriums of Renaissance theorists appeared in the palaces and villas of princes, popes, and cardinals.
Heating Methods and Their Impact on Soane's Work: Lincoln's Inn Fields and Dulwich Picture Gallery
Authors: Willmert Todd
Published: April 2006

During the years of Sir John Soane's practice, there were tremendous advancements in central heating methods. Stoves and fireplaces were no longer the primary means of heating spaces as hot air, steam, and hot water systems were introduced and gained currency. Soane designed expressive stoves, and fireplaces remained especially important to him because of their cultural associations, but he also readily recognized the possibilities of central systems and utilized them as they became available. The result is a compelling dialogue between his architecture and the diversity of available heating strategies. To understand fully Soane's manipulation of space or design intent in such major works as Lincoln's Inn Fields and Dulwich Picture Gallery, it is critical to understand his awareness of heating methods and his expertise in addressing the architectural opportunities they offered.
Inigo Jones's Site Organization at St. Paul's Cathedral: "Ponderous Masses Beheld Hanging in the Air"
Authors: Hart Vaughan
Published: April 2006

In studies of Renaissance architecture, little attention is normally given to the organization of building sites and to the way in which the practicalities of mechanics and material supplies influenced the finished works. This article describes Inigo Jones's site organization at St. Paul's Cathedral where, during the 1630s, he undertook the large and complex task of refacing the existing Gothic structure. Here practical site constraints influenced Jones's design at least as much as theoretical objectives. This study throws light on Jones's relationship with his assistant, John Webb, who oversaw much of the day-to-day work, and illustrates such details as Jones's use of craftsmen to make and amend models in perfecting his designs on-site. In this article the work's accounts are studied in order to reinterpret the few known surviving working drawings and contemporary views that record one of Jones's most important achievements.
From Episcopal to Communal Palaces: Places and Power in Northern Italy (1000-1250)
Authors: Miller Maureen C.
Published: April 2006

This article links the emergence of communal palaces in northern Italian towns to the changing juridical relationship between bishops and communes. Architectural aggrandizement and changes in the words used to describe buildings were integral to the competition for power between these new urban governments and traditional ecclesiastical lords. Bishops' palaces, and the claims to authority they represented, were important influences upon the civic palazzi built in the late twelfth and early thirteenth centuries. The chronology and historical context of the emergence of episcopal palaces links them to the formation of the communes. The bishop, of course, always had a special residence, but throughout the early Middle Ages it was identified as a domus or an episcopium; only the emperor had a palatium. Over the eleventh and early twelfth centuries, however, bishops began calling their residences palatia. This bold change in name and evidence for new constructions closely correspond with the early stages of communal organization. It was usually followed by a period of wary collaboration and intense competition between the developing commune and the bishop. Late in the twelfth century and early in the thirteenth, the balance of power between bishops and communes shifted decisively in favor of the latter, and these urban governments crowned their juridical victories architecturally, building their own palatia.
Urban Interchange in the Southern Cone: Le Corbusier (1929) and Werner Hegemann (1931) in Argentina
Authors: Collins Christiane Crasemann
Published: April 2006

The Southern Cone of the Americas, although geographically remote, had evolved in the 1920s and 1930s into a vital arena for architectural and urban ideas. For European visitors expecting a tabula rasa on which their visions and dreams could be explored, this proved to be a fiction when they encountered sophisticated local schemes and ambitions. This essay provides a look at the urban discourse in Buenos Aires and Rosario that coalesced around the presence of two international urbanists representing distinct positions: Le Corbusier and Werner Hegemann. Consideration is given to the cultural and social ambient. A historical overview of urban development and a discussion of the complex politics in the area are beyond the scope of this study.
Frank Lloyd Wright's Design for the "Capital Journal," Salem, Oregon (1932)
Authors: Johnson Donald Leslie
Published: April 2006

When American architects were arguing the pros and cons of European modernism, Wright presented a design for the Capital Journal building in Salem, Oregon, that was in response to the European's abstract, stark, boxes. Wright's letter forwarding the design drawings to his client George Putnam, published here for the first time, offers a rare glimpse into Wright's methodology for a particular design. In this case we can better understand the architectonics of the proposal, in particular the functional character of glass.
An Architecture for Modern Nerves: Josef Hoffmann's Purkersdorf Sanatorium
Authors: Topp Leslie
Published: April 2006

This reexamination of Josef Hoffmann's Purkersdorf Sanatorium (Purkersdorf, Austria, 1904-1905) takes as its starting point the fact that Hoffmann's building was built as part of a complex founded by the psychologist Richard von Krafft-Ebing as a sanatorium for nervous ailments. Krafft-Ebing believed that the modern metropolis was ruining the nervous health of its inhabitants and called for the widespread establishment of sanatoriums to treat the nervous case. The article proposes that Krafft-Ebing's appeal to the healing power of light, air, nature, simplicity, and regularity influenced Hoffmann's design for the Purkersdorf Sanatorium. Also influential, it argues, was the fact that around 1900 the scientific basis of Krafft-Ebing's physical approach to neurosis was being shaken by Sigmund Freud's psychoanalytic method. The self-consciously "technological" aspects of Hoffmann's design helped to reinforce the perception among patients that their ailments were being treated in a rational, fact-based manner.
Steam and "Sanitas" in the Domestic Realm: Baths and Bathing in Southern Italy in the Middle Ages
Authors: Caskey Jill
Published: April 2006

This study presents five little-known bathing chambers from the region of Amalfi in southern Italy. Dating from the thirteenth century, the baths define with remarkable consistency a type of structure that has not previously been identified or considered in histories of medieval architecture in the West. The study begins with an analysis of the five bathing chambers and their specific architectural features, technological remains, and domestic contexts. The diverse antecedents of the buildings, which appear in ancient Roman, medieval Italian, Byzantine, and Islamic architecture, are explored, along with the implications of this eclecticism for the history of southern Italy. Utilizing the rich array of surviving medieval documents for the region, including episcopal charters, royal decrees, and medical treatises, the study then reconstructs the economic, social, and scientific significance of the baths within medieval Amalfi. As monuments outside the traditional contexts of art production in southern Italy, the baths challenge long-standing characterizations of southern Italy's art and architecture, and point to the existence of a Mediterranean-wide balneal culture in which Byzantine, Islamic, and southern Italian communities participated.
Mansions to Margins: Modernity and the Domestic Landscapes of Historic Delhi, 1847-1910
Authors: Hosagrahar Jyoti
Published: April 2006

This essay examines the ways in which the private, domestic landscape of historic Delhi changed between 1847 and 1910. I look at Delhi's ubiquitous introverted courtyard house, the haveli, during a time of dramatic cultural dislocation. Modernity and the British colonial presence together had the consequence of fragmenting sprawling princely mansions to modest dwellings and tenement houses or redefining them as more rational and efficient homes. Tracing the transformation of the haveli in form and meaning serves as a mirror to the changes in the city during the time. In Delhi, monolithic and oppositional categorization of "traditional" and "modern" masked more complex identities as the quintessential "traditional" city grew and changed in ways that were distinctly "untraditional." The landscapes of domestic architecture reveal a city struggling to define itself as modern-on its own terms.
Mode of inheritance of dermatoglyphic pattern intensity index on fingers in five Indian populations: A comparative study between individual trait and its factor
Authors: Karmakar B. , Yakovenko K. , Kobyliansky E.
Published: April 2006

Our previous study (Karmakar et al. 2005 Ann. Hum. Biol. 32:445–468) was on 500 pedigrees of five different populations, with factor 1 comprising quantitative finger dermatoglyphics (including pattern intensity index, PII) and factor 1 controlled by major genes. The present results of a complex segregation analysis of the individual trait PII of the same five populations were compared with previous results to ascertain the extent of variation between individual trait PII and its factor (factor 1) with respect to mode of inheritance. The comparative findings are very similar in five populations, irrespective of different ethnic groups. This result suggests that the variability of their biological relevance is influenced by the same genetic component, thus representing a similar mode of inheritance with major gene involvement in all populations. Am. J. Hum. Biol. 18:377–386, 2006. © 2006 Wiley‐Liss, Inc.
Cortical and spinal abnormalities in psychogenic dystonia
Authors: Espay Alberto J. , Morgante Francesca , Purzner Jamie , Gunraj Carolyn A. , Lang Anthony E. , Chen Robert
Published: April 2006

Objective

The pathophysiology of psychogenic dystonia has not been examined, but a growing body of literature suggests that abnormal sensory input from repetitive movements can lead to plastic cortical changes. Reduced cortical and spinal inhibition is well documented in organic dystonia. We tested the hypothesis that aberrant sensory input associated with abnormal posture may cause similar abnormalities by testing patients with psychogenic dystonia.

Methods

We assessed cortical and spinal inhibitory circuits and cortical activity associated with voluntary movement in 10 patients with clinically definite psychogenic dystonia, 8 patients with organic dystonia, and 12 age‐matched healthy control subjects.

Results

Three measures of cortical inhibition, resting short‐ and long‐interval intracortical inhibition and cortical silent period, were reduced in both psychogenic dystonia and organic dystonia. Cutaneous silent period mediated by spinal circuitries was increased in psychogenic and organic dystonia. Forearm spinal reciprocal inhibition was reduced in psychogenic dystonia.

Interpretation

Psychogenic and organic dystonia share similar physiological abnormalities. Previous findings of abnormal cortical and spinal excitability in organic dystonia may, in part, be a consequence rather than a cause of dystonia. Alternatively, these findings may represent endophenotypic abnormalities that predispose to both types of dystonia. Ann Neurol 2006;59:825–834
Reactions at Very Low Temperatures: Gas Kinetics at a New Frontier
Authors: Smith Ian W. M.
Published: April 2006

Advances in experimental techniques, especially the development of the CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme) method, allow many gas‐phase molecular processes to be studied at very low temperatures. This Review focuses on the reactions of molecular and atomic radicals with neutral molecules. Rate constants for almost 50 such reactions have been measured at temperatures as low as 13 K by using the CRESU method. The surprising demonstration that so many reactions between electrically neutral species can be extremely rapid at these very low temperatures has excited interest both from theoreticians and from those seeking to understand the chemistry that gives rise to the 135 or so molecules that are present in low‐temperature molecular clouds in the interstellar medium. Theoretical treatments of these reactions are based on the idea that a reaction occurs when the long‐range potential between the reagent species brings them into close contact. The astrochemical context, theoretical studies, and the determination of the rate constants of these low‐temperature reactions are critically discussed.
Developmental toxicity evaluation of berberine in rats and mice
Authors: Jahnke Gloria D. , Price Catherine J. , Marr Melissa C. , Myers Christina B. , George Julia D.
Published: April 2006

BACKGROUND: Berberine, a plant alkaloid, is found in some herbal teas and health‐related products. It is a component of goldenseal, an herbal supplement. Berberine chloride dihydrate (BCD) was evaluated for developmental toxicity in rats and mice.

METHODS: Berberine chloride dihydrate was administered in the feed to timed‐mated Sprague–Dawley (CD) rats (0, 3625, 7250, or 14,500 ppm; on gestational days [GD] 6–20), and Swiss Albino (CD‐1) mice (0, 3500, 5250, or 7000 ppm; on GD 6–17). Ingested doses were 0, 282, 531, and 1313 mg/kg/day (rats) and 0, 569, 841, and 1155 mg/kg/day (mice).

RESULTS:There were no maternal deaths. The rat maternal lowest observed adverse effect level (LOAEL), based on reduced maternal weight gain, was 7250 ppm. The rat developmental toxicity LOAEL, based on reduced fetal body weight per litter, was 14,500 ppm. In the mouse study, equivocal maternal and developmental toxicity LOAELs were 5250 ppm. Due to scattering of feed in the high dose groups, a gavage study at 1000 mg/kg/day was conducted in both species.

CONCLUSIONS: In rats, maternal, but not fetal adverse effects were noted. The maternal toxicity LOAEL remained at 7250 ppm (531 mg/kg/day) based on the feed study and the developmental toxicity NOAEL was raised to 1000 mg/kg/day BCD based on the gavage study. In the mouse, 33% of the treated females died. Surviving animals had increased relative water intake, and average fetal body weight per litter decreased 5–6% with no change in live litter size. The maternal toxicity LOAEL remained at 5250 ppm (841 mg/kg/day) BCD, based on increased water consumption. The developmental toxicity LOAEL was raised to 1000 mg/kg/day BCD based on decreased fetal body weight. Birth Defects Research (Part B) 77:195–206, 2006. Published 2006 Wiley‐Liss, Inc.
Molecular and cellular contractile dysfunction of dystrophic muscle from young mice
Authors: Lowe Dawn A. , Williams Brian O. , Thomas David D. , Grange Robert W.
Published: April 2006

The purpose of this study was to determine whether contractile protein alterations are responsible for force deficits in young dystrophic muscle. Contractility of intact extensor digitorum longus muscles and permeabilized fibers from wild‐type (wt), dystrophin‐deficient (mdx), and dystrophin/utrophin‐deficient (mdx:utrn−/−) mice aged 21 and 35 days was determined. Myosin structural dynamics were assessed by site‐directed spin labeling and electron paramagnetic resonance spectroscopy. The principal finding was that force generation was depressed by ∼20% in mdx muscles, but fiber Ca2+‐activated force and myosin structure were not different from wt animals, suggesting that contractile proteins are not responsible for the force deficits in those muscles. For mdx:utrn−/− mice, muscle and fiber forces were ∼40% lower than wt and the fraction of strong‐binding myosin during contraction was reduced by 13%. These data indicate that contractile protein alterations, in addition to myosin dysfunction, cause force deficit in muscles from young mdx:utrn−/− mice. Elucidating the molecular mechanisms underlying muscle weakness at the onset of disease is important for designing treatment strategies. Muscle Nerve, 2006
Laminar mixing and chaotic mixing in several cavity flows
Authors: Chien W.-L. , Rising H. , Ottino J. M.
Published: April 2006

The objective of this work is an experimental study of laminar mixing in several kinds of two-dimensional cavity flows by means of material line and blob deformation in a new experimental system consisting of two sets of roller pairs connected by belts. The apparatus can be adjusted to produce a range of aspect ratios (0.067–10), Reynolds numbers (0.1–100), and various kinds of flow fields with one or two moving boundaries. Flow visualization is conducted by marking underneath the free surface of the flow with a tracer solution of low diffusivity and of approximately the same density and viscosity as the flowing fluid. The effects of the initial location of the material blob, relative motion of the two bands, and minor changes in the geometry of the flow region are investigated experimentally.

The alternate periodic motion of two bands in a cavity flow is an example of a laminar flow which might lead to chaotic mixing. The governing parameter is the dimensionless frequency of oscillation of the walls f which, under the proper conditions, is able to produce horseshoe functions of various types. The deformation of blobs is central to the understanding of mixing and can be studied to identify horseshoe functions. It is found that the efficiency of mixing depends strongly on the value of f and that there exists an optimal value of f that produces the best mixing in a given time.
Calculations of self-excited impinging jet flow
Authors: Ohring Samuel
Published: April 2006

This paper presents numerical calculations of the self-excited oscillations of an incompressible planar jet impinging upon a wedge for a Reynolds-number range of 250–650. For this Reynolds-number range these flows are experimentally observed to be two-dimensional and laminar. A finite-difference vorticity/stream-function formulation of the Navier-Stokes equations is employed. The self-sustained flow oscillations result in not just one but several well-defined flow frequency components due to nonlinear interaction of two primary components: the most unstable frequency (β) of the jet shear layer and a low-frequency modulating component ($\frac{1}{3}\beta $). The modulating component results from vortex-vortex interaction at the impingement edge of both like and counter-rotating vortices. Although the interaction pattern varies through the Reynolds-number range studied, the pattern adjusts itself to maintain the modulating component $\frac{1}{3}\beta $ which has a strong upstream influence. The numerical results, in agreement with experimental results, strongly suggest the occurrence of such phenomena as frequency jumps and hysteresis. Pressure at the wedge surface has been calculated and compared with experimental results. Numerical results for wedge torque and lift, which have not been experimentally measured, have also been obtained.
Rayleigh-Bénard convection in an intermediate-aspect-ratio rectangular container
Authors: Kolodner Paul , Walden R. W. , Passner A. , Surko C. M.
Published: April 2006

We report a study of the flow patterns associated with Rayleigh—Bénard convection in rectangular containers of approximate proportions 10 × 5 × 1 at Prandtl numbers σ between 2 and 20. The flow is studied at Rayleigh numbers ranging from the onset of convective flow to the onset of time dependence; Nusselt-number measurements are also presented. The results are discussed in the content of the theory for the stability of a laterally infinite system of parallel rolls. We observed transitions between time-independent flow patterns which depend on roll wavenumber, Rayleigh number and Prandtl number in a manner that is reasonably well described by this theory. For σ [lsim ] 10, the skewed-varicose instability (which leads directly to time dependence in much larger containers) is found to initiate transitions between time-independent patterns. We are then able to study the approach to time dependence in a regime of larger Rayleigh number where the instabilities in the flow are found to have an intrinsic time dependence. In this regime, the onset of time dependence appears to be explained by the recent predictions of Bolton, Busse & Clever for a new set of time-dependent instabilities.
Structural characteristics of a developing turbulent planar jet
Authors: Thomas F. O. , Goldschmidt V. W.
Published: April 2006

An experimental study of the developing structural characteristics of a two-dimensional jet in an extremely quiet environment was performed. The jet, at an exit Reynolds number of 6000 and with fluctuation intensity under 0.2% at the mouth, was operated within a large anechoic room. Measurements of energy spectra, fluctuation phase angles and two-dimensionality led to the inference of structural patterns in the flow. These patterns are initially characterized by relatively strong symmetric modes exhibiting limited two-dimensionality and oriented parallel to the mouth of the jet. Subsequent downstream evolution led to the formation of an antisymmetric pattern beyond the jet potential core and the associated development of extended structures possessing a definite large lateral inclination. The results of this work suggest a developing large-scale structural pattern more complicated than previously supposed.
On the skewness of sea-surface elevation
Authors: Srokosz M. A. , Longuet-Higgins M. S.
Published: April 2006

Surface skewness is a statistical measure of the vertical asymmetry of the air-sea interface – exemplified by the sharp crests and rounded troughs of surface gravity waves. Some authors have proposed a constant ratio between surface skewness and the ‘significant slope’ of the waves. Here it is shown theoretically that no such simple relation is to be expected.

Wave records are of at least two different types; Eulerian (as made with a fixed probe) or Lagrangian (as with a free-floating buoy). The corresponding statistical properties are examined. At first sight it might appear that the degree of skewness in corresponding records would be different. However it is shown that to lowest order the skewness is invariant; only the apparent mean level is different, at second order.
On the excitation of long nonlinear water waves by a moving pressure distribution. Part 2. Three-dimensional effects
Authors: Katsis C. , Akylas T. R.
Published: April 2006

The three-dimensional wave pattern generated by a moving pressure distribution of finite extent acting on the surface of water of depth h is studied. It is shown that, when the pressure distribution travels at a speed near the linear-long-wave speed, the response is governed by a forced nonlinear Kadomtsev-Petviashvili (KP) equation, which describes a balance between linear dispersive, nonlinear and three-dimensional effects. It is deduced that, in a channel of finite width 2w, three-dimensional effects are negligible if w [Lt ] h2/a, a being a typical wave amplitude; in such a case the governing equation reduces to the forced Korteweg-de Vries equation derived in previous studies. For aw/h2 = O(1), however, three-dimensional effects are important; numerical calculations based on the KP equation indicate that a series of straight-crested solitons are radiated periodically ahead of the source and a three-dimensional wave pattern forms behind. The predicted dependencies on channel width of soliton amplitude and period of soliton formation compare favourably with the experimental results of Ertekin, Webster & Wehausen (1984). In a channel for which aw/h2 [Gt ] 1, three-dimensional, unsteady disturbances appear-ahead of the pressure distribution.
Numerical simulations of nonlinear axisymmetric flows with a free surface
Authors: Dommermuth Douglas G. , Yue Dick K. P.
Published: April 2006

A numerical method is developed for nonlinear three-dimensional but axisymmetric free-surface problems using a mixed Eulerian-Lagrangian scheme under the assumption of potential flow. Taking advantage of axisymmetry, Rankine ring sources are used in a Green's theorem boundary-integral formulation to solve the field equation; and the free surface is then updated in time following Lagrangian points. A special treatment of the free surface and body intersection points is generalized to this case which avoids the difficulties associated with the singularity there. To allow for long-time simulations, the nonlinear computational domain is matched to a transient linear wavefield outside. When the matching boundary is placed at a suitable distance (depending on wave amplitude), numerical simulations can, in principle, be continued indefinitely in time. Based on a simple stability argument, a regriding algorithm similar to that of Fink & Soh (1974) for vortex sheets is generalized to free-surface flows, which removes the instabilities experienced by earlier investigators and eliminates the need for artificial smoothing. The resulting scheme is very robust and stable.

For illustration, three computational examples are presented: (i) the growth and collapse of a vapour cavity near the free surface; (ii) the heaving of a floating vertical cylinder starting from rest; and (iii) the heaving of an inverted vertical cone. For the cavity problem, there is excellent agreement with available experiments. For the wave-body interaction calculations, we are able to obtain and analyse steady-state (limit-cycle) results for the force and flow field in the vicinity of the body.
Dynamic stall due to unsteady marginal separation
Authors: Elliott J. W. , Smith F. T.
Published: April 2006

A theoretical investigation into the next stage of dynamic stall, concerning the beginnings of eddy shedding from the boundary layer near an aerofoil's leading edge, is described by means of the unsteady viscous-inviscid interacting marginal separation of the boundary layer. The fully nonlinear stage studied in the present paper is shown to match with a previous ‘weakly nonlinear’ regime occurring in the earlier development of the typical eddy from its initially slender thin state. Numerical solutions followed by linear and nonlinear analysis suggest that with confined initial conditions the strong instabilities in the present unsteady flow tend to force a breakdown within a finite time. This leads on subsequently to an unsteady predominantly inviscid stage where the eddy becomes non-slender, spans the entire boundary layer and its evolution then is governed by the Euler equations. This is likely to be followed by the shedding of the eddy from the boundary layer.
Interface conditions for two-phase displacement in Hele-Shaw cells
Authors: Reinelt D. A.
Published: April 2006

In displacing a viscous fluid from the gap between two closely spaced parallel plates, a thin film of the original fluid remains on the surface of each plate. Boundary conditions which connect the approximate equations in the region in front of the interface with the approximate solutions in the thin-film region are determined from local solutions of the equations in the vicinity of the interface edge. These interface conditions depend on both b/R (gap half-width/radius of curvature) and μUn/T, where μ is the viscosity of the original fluid, Un is the normal velocity of the interface edge, and T is the interfacial tension. These conditions are determined using perturbation method when μUn/T [Lt ] 1 and numerical methods when μUn/T is O(1). Though previous theories have shown qualitative agreement with experiments, it is hoped that these new boundary conditions improve the quantitative agreement.
Tidal rectification in lateral viscous boundary layers of a semi-enclosed basin
Authors: Swart H. E. De , Zimmerman J. T. F.
Published: April 2006

The rectified flow, induced by divergence of the vorticity flux in lateral oscillatory viscous boundary layers along the sidewalls of a semi-enclosed basin, is studied as a function of the Strouhal number, k, equivalent to the Reynolds number of the viscous inner oscillatory boundary layer, and of the Stokes number. The squared ratio of these numbers defines another Reynolds number, measuring the strength of the self-advection by the residual flow. For strong self-advection the residual current decays to zero in an outer boundary, its width being large compared to the width of the inner layer. The regimes of small, moderate and strong self-advection are analysed.
Turbulence in radial flow between parallel disks at medium and low Reynolds numbers
Authors: Tabatabai M. , Pollard A.
Published: April 2006

The radial flow of air between two closely spaced parallel disks is studied experimentally and the behaviour of the flow, especially the turbulence decay mechanism, is examined. At high Reynolds numbers the flow resembles fully developed turbulent two-dimensional channel flow. A quasi-laminar boundary layer is found to gradually replace the viscous sublayer as the Reynolds number decreases. At low Reynolds numbers, the turbulence decays and the flow gradually approaches a laminar-type profile. The decay process is shown to be very slow and indications of a weak turbulence-generating mechanism is observed even at very low Reynolds numbers. Relaminarization, rather than being an abrupt change in the state of the flow, is an eventual outcome of the turbulence decay process.
Capillary–gravity waves produced by a heaving body
Authors: Hocking L. M.
Published: April 2006

The vertical oscillation of a partially submerged body produces a surface wave that carries energy away from the body. The amplitude of this wave, when surface-tension effects are not negligible, depends on the conditions applied at the line of contact between the body and the free surface of the fluid. An edge condition that includes both dynamic variation of the contact angle and contact-angle hysteresis is used in this paper; the condition implies a dissipation of energy at the contact line. The amplitude of the wave and the amount of energy dissipated are calculated for a horizontal circular cylinder and for a simple source-and-plate model. This model is shown to be an adequate representation for the qualitative description of heaving motions and to simplify the calculations considerably. The effects of varying the relative importance of surface tension and gravity, the dynamic behaviour of the contact angle, and the amount of hysteresis, are calculated for the source-and-plate model.
Localization of gravity waves on a channel with a random bottom
Authors: Devillard Pierre , Dunlop François , Souillard Bernard
Published: April 2006

We present a theoretical study of the localization phenomenon of gravity waves by a rough bottom in a one-dimensional channel. After recalling localization theory and applying it to the shallow-water case, we give the first study of the localization problem in the framework of the full potential theory; in particular we develop a renormalized-transfer-matrix approach to this problem. Our results also yield numerical estimates of the localization length, which we compare with the viscous dissipation length. This allows the prediction of which cases localization should be observable in and in which cases it could be hidden by dissipative mechanisms.
An investigation of the growth of turbulence in a uniform-mean-shear flow
Authors: Rohr J. J. , Itsweire E. C. , Helland K. N. , Atta C. W. Van
Published: April 2006

A uniform-mean-gradient shear flow was produced using a ten-layer closed-loop water channel, providing long enough dimensionless flow development times (τ = (x/Ū) (∂ Ū/∂z)) for the turbulence to grow. The rate of growth of the turbulence compares well with similar measurements in wind-tunnel-generated uniform shear flows for which the mean shears and centreline velocities are larger by an order of magnitude. Preliminary investigations were undertaken to study the growth of the turbulent intensity as functions of the mean shear, centreline velocity, and initial disturbance lengthscales. Initial disturbance lengthscales were varied by using grids of different mesh sizes.

Turbulent intensities were found to increase nearly linearly with τ. Differences in grid mesh size produce different offsets in the turbulent intensity level, with a larger grid mesh producing a higher positive offset. This offset persists throughout the growth of the turbulent intensity. These observations provide valuable insight in interpreting previous wind-tunnel measurements, in particular the high-shear experiments of Karnik & Tavoularis (1983). Comparison with the theoretical predictions of Tavoularis (1985) allows for an improved universal characterization of evolving turbulence in a uniform mean shear.
The interaction of two spatially resonant patterns in thermal convection. Part 1. Exact 1:2 resonance
Authors: Proctor M. R. E. , Jones C. A.
Published: April 2006

The linear stability of two superimposed layers of fluid, heated from below and separated by a thin conducting plate, is investigated. It is shown that when the ratio of the depths of the layers is close to 1:2, two distinct modes of convection can occur with preferred horizontal wavenumber in the ratio 1:2. The nonlinear evolution of a disturbance consisting of both modes is considered, and it is shown that travelling waves are the preferred mode of nonlinear convection for a wide range of parameter values. Other possible types of behaviour, including modulated waves and an attracting homoclinic trajectory, are also described in detail.
Characteristics of vorticity fluctuations in a turbulent wake
Authors: Antonia R. A. , Browne L. W. B. , Shah D. A.
Published: April 2006

Measurements of the lateral components of the vorticity fluctuation have been made in the self-preserving turbulent wake of a circular cylinder. Each component was obtained separately using two X-wires separated in the appropriate lateral directions. The two velocity derivatives which make up the streamwise vorticity component were also determined but not simultaneously. An approximation to the streamwise vorticity was made from these measurements. Moments, probability density functions and spectra of the three vorticity components across the wake are presented and discussed. The high-wavenumber behaviour of the spectra is compared with calculations, based on local isotropy. Satisfactory agreement with the calculations is obtained for the lateral vorticity components over a significant high-wavenumber range. The approximated streamwise vorticity spectrum tends towards the isotropic calculation at very large wavenumbers.
A stochastic model for dispersion and concentration distribution in homogeneous turbulence
Authors: Kaplan H. , Dinar N.
Published: April 2006

A new approach to contaminant diffusion in homogeneous turbulence is proposed. This approach is based on solving for the Lagrangian trajectories of many particles taking into account the interaction among their velocities. The velocity field at a given instant is composed of many ‘eddies’ distributed randomly and uniformly in space. The velocity of each eddy is proportional to the cube root of its size. In this way the calculated Eulerian correlation function between any two points is consistent with observations. The present model is used to calculate concentration fluctuations, concentration averages and intermittency as functions of location and time. Results were found to be in accordance with experimental measurements. Probability distributions as functions of time and location are also calculated.
Slow drift of a floating cylinder in narrow-banded beam seas
Authors: Agnon Yehuda , Choi Hang S. , Mei Chiang C.
Published: April 2006

For a long cylinder floating on the sea surface, incident sea waves with a narrow frequency band excite body oscillations of short and long periods. Depending on the stiffness of the mooring system, the body displacement of the long-period motion can be comparable with, or even greater than that of the short-period oscillations. By combining the asymptotic methods of multiple scales and inner and outer expansions, we describe an essentially analytical theory for slow sway of both small and large amplitudes. Besides showing results for various quasi-steady and transient incident waves for a rectangular cylinder, we examine the effect of the gap between the keel of the body and the sea bottom. It is found in particular that a small gap can enhance moderate resonance by blocking the flow due to long waves and increase the apparent mass of the cylinder. Real-fluid effects are not included.