bluuebunny/crossref_metadata_2025 huggingface dataset:
The Bank of Commerce by Asa Beebe Cross: "A Building of the Latest Architecture"
Authors: Ehrlich George
Published: April 2006

A commission in 1883 for a bank "of the latest style" led Asa Beebe Cross to travel extensively as a prelude to designing the Bank of Commerce in Kansas City, Missouri. Cross chose to adapt the style of Frank Furness, especially that of the Provident Bank in Philadelphia. Analysis of relevant documents in the Cross Family Papers, and of contemporary commentaries, provides an insight into architectural practice of the period, and why the Furness style was selected by an architect not otherwise sympathetic to the "latest styles."
Ransome at Bayonne
Authors: Banham Reyner
Published: April 2006

The Anglo-Californian engineer, Ernest L. Ransome, has a secure place in the annals of reinforced concrete because of the very large number of patents issued to him in the last two decades of the 19th century. At the end of the sequence, in 1902, comes a patented "system" which foreshadows modern concrete-framed factory-construction. Ransome clearly understood the difference between wall-and-window and frame-and-fill, but the building where he made the change, the Pacific Coast Borax plant at Bayonne, New Jersey, has been overlooked so far by historians. The article gives a brief account of the structure, which is still standing in all its crucial parts, and attempts an assessment of its historical importance for later developments, such as the rise of the International Style.
Carlo Rainaldi's Façade Project for S. Lorenzo in Lucina
Authors: Habel Dorothy Metzger
Published: April 2006

Recently discovered documents record Carlo Rainaldi's work on the convent facility at the church of S. Lorenzo in Lucina in Rome. In addition, a Rainaldi drawing found in the archives demonstrates the architect's project to redesign radically the façade of the church. The design is modest and was never executed, but the project is clearly related to Rainaldi's work at S. Maria in Campitelli. Moreover, the façade design suggests a new dimension of Alexander VII's planning for this area of the city.
Bouvard's Boulevards: Beaux-Arts Planning in Istanbul
Authors: Çelik Zeynep
Published: April 2006

From the early 18th century on, the ruling elite of the Ottoman Empire equated European civilization with progress. Not only technological innovations, but also social, cultural, and aesthetic values of the Western World were warmly embraced. A renovation project prepared in 1902 for the imperial capital, Istanbul, reflected this attitude in the field of urban design and architecture. Its author was a prominent Beaux-Arts-trained Parisian architect, Joseph Antoine Bouvard. Bouvard's five large-sized watercolor drawings, now in the Istanbul University Library, depict his proposals for the Hippodrome, Beyazit Square, Valide Square, and the Galata Bridge. The Hippodrome is made a geometrically landscaped park; Beyazit Square is converted into a civic center; the new Valide Square duplicates the Trocadero scheme of the 1878 Paris International Exposition; and the design features of the 1900 Pont Alexandre III in Paris are adopted for the Galata Bridge. Largely disregarding the architectural heritage as well as the geographical characteristics of the capital, the architect proposed a major facelifting operation with the intention of turning Istanbul into the Paris of the East. Although the abstract nature of this project made its application impossible, the image, transmitted through Bouvard's masterful drawings, enjoyed a great deal of praise from Sultan Abdülhamit II and his entourage. This article analyzes Bouvard's avant-projet against the background of early-20th-century Istanbul's urban fabric.
John Vanbrugh's Architecture: Some Sources of His Style
Authors: McCormick Frank
Published: April 2006

This essay posits three basic sources for the vocabulary of Vanbrugh's mixed style: namely, (1) the interior architecture and scene design of the contemporary theatre, with which Vanbrugh became familiar in his capacity as dramatist and manager of the Queen's Theatre at the Haymarket; (2) the medieval forms of the walled city of Chester in which he spent his youth; and (3) the donjon and courtyards of the Chateau of Vincennes, which Vanbrugh would have come to know during his imprisonment there in 1691. The first two operate as rather general sources of the "theatrical" and the "medieval" elements in Vanbrugh's buildings. In the case of the Chateau of Vincennes the influence is more specific: the arrangement of the Chateau's donjon and courtyards supplied a model for the typical design of Vanbrugh's large-scale buildings in which forward-thrusting wings are attached to a deeply recessed centerblock. David Cast's neo-Hobbesian suggestions for "seeing" Vanbrugh are invoked as a means of making aesthetic sense of Vanbrugh's use of his three sources.
The Balliol That Might Have Been: Pugin's Crushing Oxford Defeat
Authors: Litvack Leon B.
Published: April 2006

Augustus Welby Pugin (Fig. 1) was the acknowledged leader of the Gothic revival in 19th-century England. Examples of his work appear everywhere in the country-everywhere, that is, except Oxford. This man was guided by strict principles of "pointed" or "Christian" architecture; however, unlike many architects of his day, Pugin's beliefs were also governed by a fervent-and sometimes oppressive-devotion to the Roman Catholic Church. He was convinced that outward signs of devotion were indispensable, and that the Church of Rome was the true expounder of Christian faith. Pugin would have loved to erect a building based on these principles in what he called "the most Catholic-looking city in England." The aim of this article is to demonstrate that the rejection of Pugin as architect for the new buildings at Balliol in 1843 was not simply a case of a Roman Catholic's working in a hostile Protestant environment; rather, he was dismissed because of the vehemence with which he pressed his own cause and derided that of others. Balliol was a great loss to Pugin; the course of events described in these pages serves as a painful reminder of overabundant zeal in pursuit of a goal.
Architecture for the Boston & Albany Railroad: 1881-1894
Authors: Ochsner Jeffrey Karl
Published: April 2006

Between 1881 and 1894 the Boston & Albany Railroad undertook a major program of capital investment and improvements to the physical facilities of the line, including the construction of over 30 new passenger stations. H. H. Richardson's close friends, James A. Rumrill and Charles S. Sargent, as the two members of the B&A Board most interested in construction, were given responsibility for this program. They directed the commissions to Richardson and after his death to his successors, Shepley, Rutan and Coolidge. Richardson's nine B&A station designs were generally variations on a simple theme-small rectangular stone blocks with overhanging roofs providing sheltered waiting space at trackside. The continuation of this approach by Shepley, Rutan and Coolidge in 23 additional station designs resulted in a remarkable consistency of character and quality throughout the B&A system. This consistency was also fostered by the continuing participation of Norcross Brothers of Worcester (Richardson's "Master Builder") as contractor, and by the participation of F. L. Olmsted, whose design of landscaped settings for many of the stations contributed to the establishment of the B&A program of "railroad gardening." While the stations were small commissions, the totality of the B&A program represents an impressive collaboration of designer, contractor, and client which has seldom been equalled.
The Francesco di Giorgio Material in the Zichy Codex
Authors: Kolb Carolyn
Published: April 2006

The purpose of this article is to describe and analyze part of the contents of an Italian manuscript and model book compiled in Venice by Angelo dal Cortivo between 1489 and 1536-the Zichy Codex, now in Szabó Ervin Központi Könyvtár (Erwin Szabo Public Library), Budapest. This analysis demonstrates that the contents of the manuscript represent the earliest version thus far discovered of Francesco di Giorgio Martini's first treatise as found in Saluzzianus 148, Biblioteca Reale, Turin. The article proceeds from an account of the history of the manuscript, including an extensive bibliography and unpublished documents for the life of its compiler, to comparisons of the material in the Zichy Codex with that in Saluzzianus 148 of the Biblioteca Reale, Turin. A list, paragraph by paragraph, of the contents and their parallels in the Turin manuscript is found in Table I. Table II compares the subject matter organization of the two texts. Textual and visual material from the Zichy Codex is discussed, showing that it contains material not found in other Francesco di Giorgio texts, that the understanding of Vitruvius found in the Zichy Codex is poorer than that demonstrated in Saluzzianus 148, and that a purposeful re-organization of the material in the Zichy Codex occurred before the writing of the Turin manuscript. A date in the 1460s is proposed for the Francesco di Giorgio material found in the Zichy Codex.
A Drawing for the Façade of Giulio Romano's House in Mantua
Authors: Magnusson Børje
Published: April 2006

This article presents a newly discovered drawing for the façade of Giulio Romano's House in Mantua. It is argued that the drawing shows successive ideas for the façade which preceded the eventual executed solution. Restorations in the 19th century have partly obscured the architect's design, which can be better appreciated with reference to the newly discovered drawing.
Ludwig Mies van der Rohe and Egon Eiermann: The Dictate of Order
Authors: Boyken Immo , Oestmann Hans J.
Published: April 2006

A comparison of the works of two of Germany's most important architects, Ludwig Mies van der Rohe and Egon Eiermann, reveals two similar but subtly different approaches to theory and design in the years following World War II. While there is no evidence of a close personal relationship between the two architects, their theoretical views were largely compatible. Both believed in the "universal validity" of pre-determined architectural forms, and they adhered closely to the principle of architectural "order." Eiermann's designs, however, are never as rigid as those of Mies, and he made many more allowances for technology and human need in his buildings. As a result, Eiermann's architecture is characterized today by a certain charm that sets it apart from the strict formalism of Mies van der Rohe.
Carlo Rainaldi, Nicola Michetti, and the Patronage of Cardinal Giuseppe Sacripante
Authors: Kelly Cathie C.
Published: April 2006

The chapel dedicated to Beata Lucia in the cathedral of Narni has been attributed to Nicola Michetti on the basis of both style and the fact that he had worked elsewhere for the patron, Cardinal Giuseppe Sacripante. The configuration of the altar surround, however, is not typical of Michetti's work. That structure, in fact, is by Carlo Rainaldi and originally stood in the chapel of S. Antonio di Padova in SS. Apostoli in Rome. Sacripante purchased the altar surround in October 1711 and had it set up in Narni sometime between 1712 and 1714. Michetti's contribution to the design of the chapel, therefore, is limited to the revetment of the walls, the windows, and the transverse oval dome. Rainaldi's altar surround is an important find. Conceived in 1652 and constructed between 1654 and c. 1656, it is the immediate forerunner of his urbanistic masterpieces of the early 1660s, S. Maria di Montesanto and S. Maria dei Miracoli, on piazza del Popolo.
Some Observations about the Romanesque Choir of Ely Cathedral
Authors: Mcaleer J. Philip
Published: April 2006

Due to the collapse of the Romanesque central tower in 1322, the original eleventh-century choir of Ely Cathedral has been almost totally rebuilt. However, a few fragments remain to suggest something about its original form. The responds marking the entrance to the vanished apse are the major and most conspicuous survivors. Somewhat similar shafts at the west end of the choir, adjacent to the piers of the fourteenth-century Octagon, have recently been interpreted as evidence that the choir elevation possessed vertical articulation. A close examination of these western shafts reveals that they are actually fourteenth-century, not eleventh-century, masonry. The choir, therefore, most likely was, like the early south transept arm, not vertically articulated. It may also not have had alternating supports, unlike the transept. Other traces of the choir remain at gallery and clerestory levels. One of the most interesting fragments is located in the north clerestory, behind the respond of the lost apse. Here is found evidence of a newel stair in a position similar to one of a pair at nearby Peterborough Abbey, where they are associated with an apse, as was likely the case at Ely. These features, as well as the lack of a crypt, may further distance the choir of Ely from its supposed model, Winchester Cathedral, begun in 1079.
A Rational, National Architecture: Viollet-le-Duc's Modest Proposal for Russia
Authors: O'Connell Lauren M.
Published: April 2006

Viollet-le-Duc earned a privileged place in the annals of modern architecture by elaborating a general theory that could respond flexibly to a variety of local traditions, cultural practices, and material resources. In 1877 he undertook to test this theory by applying it to an unfamiliar case-the architecture of Russia. The first study of its type to appear in the West, L'Art russe chronicled Russia's architectural past and predicted its future. The book touched a nationalist nerve in the Russian audience and engendered a heated debate in Russia about the nation's ethnic identity and architectural destiny. Analysis of the text and its critical reception will demonstrate the political timeliness of Viollet-le-Duc's argument for the eminent rationality of allowing national traditions, tastes, and resources to inspire the architect's design choices.
What Do Victorian Churches Mean? Symbolism and Sacramentalism in Anglican Church Architecture, 1850-1870
Authors: Hall Michael
Published: April 2006

In a challenging but little-studied article published in Architectura in 1985, David B. Brownlee argued that the religious concept of the development of doctrine influenced the belief of architects in the Anglican Church in the 1840s that they should attempt to "develop" architecture in a radical new direction. The result was the style we now call "High Victorian." This article takes up Professor Brownlee's argument in two ways. First, it looks at how architects in the 1850s sought to create a progressive style by drawing on ideas and images from contemporary science, specifically geology, for which development was also a key word. Second, it addresses the question of why the idea of development fell so suddenly from favor in avant-garde architectural circles in the 1860s. It argues that as science and religion withdrew into their separate spheres, architects turned instead to an ideal based not on historical development but on the imitation of a stylistic paradigm. This approach was influenced by High Church belief that the sacraments, most importantly the Eucharist, were the material realization of a timeless supernatural reality. Changing attitudes to time and precedent had important consequences for the way architects viewed restoration, archaeology, and the use of historical models.
Washington and Ottawa: A Tale of Two Embassies
Authors: Gournay Isabelle , Loeffler Jane C.
Published: April 2006

In 1927, when the United States and Canada established their first relatively unpretentious legations in Ottawa and Washington, no one imagined how quickly they would become functionally and symbolically obsolete. By the end of World War II, both countries were seeking to expand their office space, and by the late 1960s, they were looking for ways to build new buildings. Each understood that the challenge was how most effectively to enhance the building's diplomatic presence. At the same time, planners in both capitals saw these projects as means of reinforcing the city's governmental core and promoting urbanity and civic identity. They encouraged the two governments to choose conspicuous downtown locations of great symbolic significance. Arthur Erickson designed the Canadian Embassy (1981-89), which stands on Pennsylvania Avenue at the foot of Capitol Hill, and David M. Childs headed the team at Skidmore, Owings & Merrill that designed the U. S. Embassy (1994-99) for an equally prominent site across from Ottawa's Parliament. Both architects faced daunting challenges: how to create a multipurpose structure to accommodate an array of different government offices; how to make a bold statement of national identity while showing respect for the host city and its urban design; and how to reconcile openness and accessibility with ever-increasing demands for security. This study examines architecture's role in public diplomacy and uses the two chanceries to explore the process through which design becomes purposeful civic achievement.
Molecular genetic analysis of Wanggu remains, Inner Mongolia, China
Authors: Fu Yuqin , Zhao Han , Cui Yinqiu , Zhang Quanchao , Xu Xuelian , Zhou Hui , Zhu Hong
Published: April 2006

The Wanggu tribe, which contributed significantly to the foundation of the Yuan Dynasty, was one of the groups living on the Mongolian steppes during the Jin‐Yuan period (AD 1127–1368) of Chinese history. However, there has been both archaeological and historical dispute regarding the origin of the ancient tribe. Recently, we discovered human remains of the Wanggu tribe in the Chengbozi cemetery in the Siziwang Banner of Inner Mongolia, China. To investigate the genetic structure of the Wanggu tribe and to trace the origins of the tribe at a molecular level, we analyzed the control‐region sequences and coding regions of mitochondrial DNA (mtDNA) from the remains by direct sequencing and restriction‐fragment length polymorphism analysis. In combination with mtDNA data of 15 extant Eurasian populations, we performed phylogenetic analysis and multidimensional scaling analysis. Our results show that the genetic structure of the Wanggu tribe in the Jin‐Yuan period is a complex matriline, containing admixture from both Asian and European populations. In addition, we reveal that on the basis of mtDNA data, the ancient tribe may share a recent common ancestor with the Turkic‐speaking Uzbeks and Uighurs. Am J Phys Anthropol, 2007. © 2006 Wiley‐Liss, Inc.
Volume and process of care in high‐risk cancer surgery
Authors: Birkmeyer John D. , Sun Yating , Goldfaden Aaron , Birkmeyer Nancy J.O. , Stukel Therese A.
Published: April 2006

BACKGROUND

Although relations between procedure volume and operative mortality are well established for high‐risk cancer operations, differences in clinical practice between high‐volume and low‐volume centers are not well understood. The current study was conducted to examine relations between hospital volume, process of care, and operative mortality in cancer surgery.

METHODS

Using the Medicare claims database (2000‐2002), we identified all patients undergoing major resections for lung, esophageal, gastric, liver, or pancreatic cancer (n = 71,558). Preoperative, intraoperative, and postoperative processes of care potentially related to operative mortality were identified from inpatient, outpatient, and physician claims files using appropriate International Classification of Diseases – Clinical Modification (ICD‐9) and Current Procedural Terminology (CPT) codes. We then assessed variation in the use of each process according to hospital volume, adjusting for patient characteristics and procedure type. Study Participants were US Medicare patients. The main outcome measure was specific processes of care.

RESULTS

Relative to those at low‐volume centers (lowest 20th by volume), patients at high‐volume hospitals (highest 20th) were significantly more likely to undergo stress tests (odds ratio [OR]: 1.51, 95% confidence interval [CI]: 1.21‐1.87), but not other preoperative imaging tests. They were more likely to see medical or radiation oncologists (OR: 1.37, 95% CI: 1.16‐1.62), but not other specialists, preoperatively. Although blood transfusions and use of epidural pain management did not vary significantly by volume, patients at high‐volume hospitals had significantly longer operations and were more likely to receive perioperative invasive monitoring (OR: 2.56, 95% CI: 1.82‐3.60). Differences in measurable processes of care did not explain volume‐related differences in operative mortality to any significant degree.

CONCLUSIONS

Although high‐volume and low‐volume hospitals differ with regard to many aspects of perioperative care, mechanisms underlying volume–outcome relations in high‐risk cancer surgery remain to be identified. Cancer 2006. © 2006 American Cancer Society.
Stepwise Sulfuration of the Terminal Phosphido Complex trans‐[PtCl(PHCy2)2(PCy2)]: Synthesis of [Pt(κ2S,S′‐PS2Cy2)(PHCy2)2]Cl and [Pt(κ2S,S′‐PS2Cy2){κP‐P(S)Cy2}(PHCy2)] and Crystal Structure of [Pt(κ2‐S,S‐PCy2S2)(κ‐S‐PCy2S2)(PHCy2)]
Authors: Gallo Vito , Latronico Mario , Mastrorilli Piero , Nobile Cosimo Francesco , Ciccarella Giuseppe , Englert Ulli
Published: April 2006

The terminal phosphido complex trans‐[PtCl(PHCy2)2(PCy2)] (1) has been prepared, exploiting the reversibility of the reaction with HCl, by action of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) on [PtCl(PHCy2)3]Cl, and its reactivity towards elemental sulfur studied. The first product obtained by reaction of 1 with 1 equiv. of sulfur is trans‐[PtCl(PHCy2)2{κP‐P(S)Cy2}] (2), which rapidly isomerises in halogenated solvents into cis‐[PtCl(PHCy2)2{κP‐P(S)Cy2}] (3). Further addition of sulfur causes the formation of a mixture of [Pt(κ2S,S′‐PS2Cy2)(PHCy2)2]Cl (4) and [Pt(κ2S,S′‐PS2Cy2){κP‐P(S)Cy2}(PHCy2)] (5), which could be selectively synthesised; the first upon sulfuration of pure 3 and the second by reaction of 4 with 1 equiv. of sulfur in the presence of DBU. Complex 5 can be further sulfurated to [Pt(κ2S,S′‐PCy2S2)(κS‐PCy2S2)(PHCy2)] (6), which is fluxional in solution and was also characterised by single‐crystal X‐ray diffraction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
An Efficient and Facile Synthesis of Capsaicin‐Like Compounds as Agonists of the TRPV1 Receptor
Authors: Tran Van H. , Kantharaj Ravi , Roufogalis Basil D. , Duke Colin C.
Published: April 2006

A new versatile synthetic route is described for the preparation of capsaicin‐like molecules which contain an α‐hydroxy ketone functional group mimicking the amide functional group in the capsaicin structure. The key reaction in this synthesis was the formation of α‐(dimethylamino)alkanenitriles as intermediates. These nitriles were successfully prepared from both aliphatic and aromatic aldehydes by reaction with dimethylamine and aqueous sodium cyanide. Treatment of the nitriles with lithium diisopropylamide (LDA) followed by reaction with various aldehydes led to the formation of α‐hydroxy ketone compounds, examples of which include 2‐hydroxy‐1‐(4‐hydroxy‐3‐methoxyphenyl)dodecan‐3‐one,(5R)‐ and (5S)‐2‐hydroxy‐1‐(4‐hydroxy‐3‐methoxyphenyl)‐5,9‐dimethyldec‐8‐en‐3‐one, representing novel capsaicin‐like molecules. Formation of (4‐benzyloxy‐3‐methoxyphenyl)acetaldehyde was also described from the Wittig reaction of 4‐benzyloxy‐3‐methoxybenzadehyde with an ylide reagent (methoxymethyl)triphenylphosphonium bromide followed by acid hydrolysis to form the title compound. This aldehyde represents a useful precursor for the synthesis of capsaicin‐like structures.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
On the steady solutions of the problem of Rayleigh–Taylor instability
Authors: Tan M. J.
Published: April 2006

The problem of Rayleigh–Taylor instability is reexamined within the framework of incompressible, inviscid and irrotational fluid flow in a bounded three-dimensional domain. A relation proposed by Pimbley (1976) between the slope and the amplitude of the interface at the rigid boundary is adopted as the interface boundary condition. Steady solutions are derived in approximate form by using bifurcation theory. It is shown that under the conditions given some of the steady solutions exhibit the features of the well-known bubbles-and-spikes configuration and can be stable to infinitesimal disturbances.
Eulerian and Lagrangian aspects of surface waves
Authors: Longuet-Higgins M. S.
Published: April 2006

Surface waves can be recorded in two kinds of ways, either with a fixed (Eulerian) probe or with a free-floating (Lagrangian) buoy. In steep waves, the differences between corresponding properties can be very marked.

By a simple physical model and by accurate calculation it is shown that the Lagrangian wave period may differ from the Eulerian wave period by as much as 38 %. The Lagrangian mean level is also higher than the Eulerian mean, leading to possible discrepancies in remote sensing of the ocean from satellites.

Surface accelerations are of interest in relation to the incidence of breaking waves, and for interactions between short (gravity or capillary) waves and longer gravity waves. Eulerian accelerations tend to be very non-sinusoidal, with large downwards peaks, sometimes exceeding -gin magnitude, near to sharp wave crests. Lagrangian accelerations are much smoother; for uniform gravity waves they lie between −0.388gand +0.315g. These values are verified by laboratory experiments. In wind-generated waves the limits are probably wider.

In progressive gravity waves in deep water the horizontal accelerations generally exceed the vertical accelerations. In steep waves, the subsurface accelerations can slightly exceed those at the free surface.

A novel application is made to the rolling motion of ships. In very steep, irrotational waves it is shown theoretically that the flow near the wave crest can lead to the rotation of the hull through angles up to 120° by a single wave, even if the wave is not breaking. This is confirmed by simple experiments. The efficiency of the keel appears to promote capsizing.
Remarks on a paper by Aref and Flinchem
Authors: Pierrehumbert R. T.
Published: April 2006

It is shown that the vortex filament in background shear considered in Aref & Flinchem (1984) is unstable to infinitesimal disturbances, and that the numerical results described therein are consistent with the characteristics of the instability.
Maximal two-layer exchange through a contraction with barotropic net flow
Authors: Armi L. , Farmer D. M.
Published: April 2006

The gravitational exchange of two fluids with different densities between reservoirs connected by a channel of constant depth and slowly varying breadth is analysed as a problem of internal hydraulics. It is shown that maximal two-way exchange with a net barotropic flow requires the presence of two controls, one at the narrrowest section and a second or ‘virtual’ control lying to one side of the narrowest section. The two controls are connected by a subcritical region, but are separated from subcritical conditions in the reservoirs by supercritical flow and stationary internal bores. Solutions are found for maximal exchange without a net barotropic component, in which case the problem is similar to that first examined by Stommel & Farmer (1953). The Stommel & Farmer analysis is shown to be a rather special limiting example of submaximal exchange, not generally applicable to natural flows. The addition of a net barotropic flow yields a range of different flow types, including maximal exchange, one-layer baroclinic flow, one-layer barotropic flow, submaximal flow governed by a reservoir condition and two-layer unidirectional flow. The maximal-exchange solution is integrated for periodic barotropic flow.
The neutral curve for stationary disturbances in rotating-disk flow
Authors: Malik Mujeeb R.
Published: April 2006

The neutral curve for stationary vortex disturbances in rotating-disk flow is computed up to a Reynolds number of 107 using the sixth-order system of linear stability equations which includes the effects of streamline curvature and Coriolis force. It is found that the neutral curve has two minima: one at R = 285.36 (upper branch) and the other at R = 440.88 (lower branch). At large Reynolds numbers, the upper branch tends to Stuart's asymptotic solution while the lower branch tends to a solution that is associated with the wave angle corresponding to the direction of zero mean wall shear.
A numerical solution of the second-order wave-diffraction problem for a submerged cylinder of arbitrary shape
Authors: Vada Torgeir
Published: April 2006

The first- and second-order wave-diffraction problems are solved for a submerged cylinder of arbitrary shape by the integral-equation method based on Green's theorem. The integral equation is solved by an element method using cubic splines. The first- and second-order force components, transmission and reflection coefficients are presented for two fifferent contours. The results for the circular contour are compared with experimental results.
A wake source model for airfoils with separated flow
Authors: Parkinson G. V. , Yeung W.
Published: April 2006

In an extension of an earlier potential-flow theory using conformal mapping and source singularities in the wake region to simulate two-dimensional bluff-body flow, new mapping sequences and additional boundary conditions are presented for the application of the method to lifting airfoils fitted with upper-surface spoilers or lower-surface split flaps of arbitrary size, location, and erection angle. The only empirical input is the base pressure coefficient. Calculations are presented of pressure distribution and lift for several cases of a Joukowsky airfoil fitted with a spoiler or a split flap, and these results are compared with experimental data from wind tunnel tests. Good agreement is found.
The stability of inviscid flows over passive compliant walls
Authors: Yeo K. S. , Dowling A. P.
Published: April 2006

The linear temporal stability of incompressible semi-bounded inviscid parallel flows over passive compliant walls is studied. It is shown that some of the well-known classical results for inviscid parallel flows with rigid boundaries can, in fact, be extended in modified form to passive compliant walls. These include a result of Rayleigh (1880) which shows that the real part of the phase velocity of a non-neutral disturbance must lie within the range of the velocity distribution; the semi-circle theorem of Howard (1961) and a result of Høiland (1953) which places a bound on the temporal amplification rates of unstable disturbances. The bounds on the phase velocity and the temporal amplification rates of unstable two-dimensional disturbances provide useful guides for numerical studies.

The results are valid for a large class of passive compliant walls. This generality is achieved through a variational-Lagrangian formulation of the essential dynamics of wall motion. A general treatment of the marginal stability of thin shear flows over general passive compliant walls is given. It represents a generalization of the analysis given by Benjamin (1963) for membrane and plate surfaces. Sufficient conditions for the stability of thin shear flows over passive compliant walls are deduced. The applications of the stability criteria to simple cases of compliant wall are described to illustrate the use and the effectiveness of these criteria.
A description of the organized motion in the turbulent far wake of a cylinder at low Reynolds number
Authors: Antonia R. A. , Browne L. W. B. , Bisset D. K. , Fulachier L.
Published: April 2006

The topology of the organized motion has been obtained in the slightly heated self-preserving far wake of a circular cylinder at a Reynolds number, based on the cylinder diameter, of about 1200. In a frame of reference moving with the organized motion, the toplogy in the plane of main shear reduces to a succession of centres and saddles, located at about the wake half-width. Centres are identifiable by large values of spanwise vorticity associated with the coherent large-scale motion. Saddles occur at the intersection of converging and diverging separatrices, the latter being identifiable with the high strain rate due to the large-scale motion. Large values of the longitudinal turbulence intensity associated with the smaller-scale motion occur at the centres. High values of the normal and shear stresses, the temperature variance and heat fluxes associated with the large-scale motion occur on either side of each saddle point along the direction of the diverging separatrix. Contours for the production of energy and temperature variance associated with the small-scale motion are aligned along the diverging separatrices, and have maxima near the saddle point. Contours for one component of the dissipation of small-scale temperature variance also have a high concentration along the diverging separatrix. Flow visualizations in the far wake suggest the existence of groups of three-dimensional bulges which are made up of clusters of vortex loops.
Systematic forcing of large-scale geophysical flows by eddy-topography interaction
Authors: Holloway Greg
Published: April 2006

The interaction of eddies with variations in topography, together with a tendency for large-scale wave propagation, generates a systematic stress which acts upon large-scale mean flows. This stress resists the midlatitude tropospheric westerlies, resists the oceanic Antarctic Circumpolar Current, and may be a dominant mechanism in driving coastal undercurrents. Associated secondary circulation provides a systematic upwelling in coastal oceans, pumping deeper water onto continental shelf areas. The derivation rests in turbulence closure theory and is supported by numerical experiments.
A boundary-element analysis of flagellar propulsion
Authors: Phan-Thien N. , Tran-Cong T. , Ramia M.
Published: April 2006

The swimming of a flagellar micro-organism by the propagation of helical waves along its flagellum is analysed by a boundary-element method. The method is not restricted to any particular geometry of the organism nor does it assume a specific wave motion for the flagellum. However, only results for an organism with a spherical or ellipsoidal cell body and a helically beating flagellum are presented here.

With regard to the flagellum, it is concluded that the optimum helical wave (amplitude α and wavenumber k) has αk ≈ 1 (pitch angle of 45°) and that for the optimum flagellar length L/A = 10 (L being the flagellar length, A being the radius of the assumed spherical cell body) the optimum number of wavelengths Nλ is about 1.5. Furthermore there appears to be no optimal value for the flagellar radius a, with the thinner flagella being favoured. These conclusions show excellent quantitative agreement with those of slender-body theory.

For the case of an ellipsoidal cell body, the optimum aspect ratios B/A and C/A of the ellipsoid are about 0.7 and 0.3 respectively; A, B and C are the principal radii of the ellipsoid. These and all of the above conclusions show good qualitative agreement with experimental observations of efficiently swimming micro-organisms.
Natural convection in vertical enclosures containing simultaneously fluid and porous layers
Authors: Beckermann C. , Viskanta R. , Ramadhyani S.
Published: April 2006

A numerical and experimental study is reported of natural convection in a vertical rectangular fluid enclosure that is partially filled with a fluid-saturated porous medium. Velocities, stresses, temperatures, and heat fluxes are assumed to be continuous across the fluid/porous-medium interface, and the conservation equations for the fluid and the porous regions are combined into a single set of equations for numerical solution. Thermocouples as well as a Mach-Zehnder interferometer are used to measure temperature distributions and infer fluid flow patterns within the fluid and the porous medium. For various test cells, porous-layer configurations and fluid-solid combinations, the model predictions show excellent agreement with the experimental measurements. It is found that the intensity of natural convection is always much stronger in the fluid regions, while the amount of fluid penetrating into the porous medium increases with increasing Darcy and Rayleigh numbers. The degree of penetration of fluid into the porous medium depends strongly on the porous-layer geometry and is less for a horizontal porous layer occupying the lower half of the test cell. If penetration takes place, the flow patterns in the fluid regions are significantly altered and the streamlines show cusps at the fluid/porous-medium interfaces. For a high effective-thermal-conductivity porous medium, natural convection in the medium is suppressed, while the isotherms bend sharply at the fluid/porous-medium interface.
Jeffery-Hamel boundary-layer flows over curved beds
Authors: Eagles P. M.
Published: April 2006

We find certain exact solutions of Jeffery-Hamel type for the boundary-layer equations for film flow over certain beds. If β is the angle of the bed with the horizontal and S is the arclength these beds have equation sin β = (const.)S−3, and allow a description of flows on concave and convex beds. The velocity profiles are markedly different from the semi-Poiseuille flow on a plane bed.

We also find a class of beds in which the Jeffery-Hamel flows appear as a first approximation throughout the flow field, which is infinite in streamwise extent. Since the parameter γ specifying the Jeffery-Hamel flow varies in the streamwise direction this allows a description of flows over curved beds which are slowly varying, as described in the theory, in such a way that the local approximation is that Jeffery-Hamel flow with the local value of γ. This allows the description of flows with separation and reattachment of the main stream in some cases.
Three-dimensional instability of a plane free shear layer: an experimental study of the formation and evolution of streamwise vortices
Authors: Lasheras J. C. , Choi H.
Published: April 2006

The three-dimensional development of a plane free shear layer subjected to small sinusoidal perturbations periodically placed along the span is experimentally studied. Both laser induced fluorescence and direct interface visualization are used to monitor the interface between the two fluids. The development of the different flow stabilities is obtained through analysis of the temporal and spatial evolution of the interface separating the two streams. It is shown that the characteristic time of growth of the two-dimensional shear instability is much shorter than that of the three-dimensional instability. The primary Kelvin-Helmholtz instability develops first, leading to the formation of an almost two-dimensional array of spanwise vortex tubes. Under the effect of the strain field created by the evolving spanwise vortices, the perturbed vorticity existing on the braids undergoes axial stretching, resulting in the formation of vortex tubes whose axes are aligned with the principal direction of the positive strain field. During the formation of these streamwise vortex tubes, the spanwise vortices maintain, to a great extent, their two-dimensionality, suggesting an almost uncoupled development of both instabilities. The vortex tubes formed through the three-dimensional instability of the braids further undergo nonlinear interactions with the spanwise vortices inducing on their cores a wavy undulation of the same wavelength, but 180° phase shifted with respect to the perturbation. In addition, it is shown that owing to the nature of the three-dimensional instability, the effect of vertical and axial perturbations are coupled. Finally, the influence of the amplitude and wavelength of the perturbation on the development of the two- and three-dimensional instabilities is described.
Electrically driven vortices in a strong magnetic field
Authors: Sommeria Joël
Published: April 2006

A steady isolated vortex is produced in a horizontal layer of mercury (of thickness a), subjected to a uniform vertical magnetic field. The vortex is forced by an electric current going from an electrode in the lower plane to the circular outer frame. The flow is investigated by streak photographs of small particles following the free upper surface, and by electric potential measurements. The agreement with the asymptotic theory for high values of the Hartmann number M is excellent for moderate electric currents. In particular all the current stays in the thin Hartmann layer of thickness a/M, except in the vortex core of horizontal extension a/M½. For higher currents, the size of the core becomes larger and depends only on the local interaction parameters. When the current is switched off, we measure the decay due to the Hartmann friction. A similar study is carried out for a vortex created by an initial electric pulse, and for a pair of vortices of opposite sign. For all these examples, the dynamics can be described by the two-dimensional Navier-Stokes equations with Hartmann friction, except in the vortex cores. Finally a vortex is produced near a lateral wall and a detachment of the boundary layer parallel to the magnetic field occurs, by which a second vortex of opposite sign is generated.
A new approximate expression for the response of a hot-wire anemometer
Authors: Nishioka Michio , Asai Masahito
Published: April 2006

Bruun's (tabulated) universal function for the response of a hot-wire anemometer is examined in detail to see if the function has some unique relationship with King's law. As a result of the analysis, an approximate expression is derived and proposed for the response over a wide range of wind speeds. Although the expression is like King's law with an additional correction term and is thus quite simple in form, it agrees with Bruun's universal function (and also with the derivative, i.e. the velocity sensitivity) to within 3% over the range of wind speeds from 2 to 120 m/s. There is little doubt that the proposed response equation may serve as a helpful guide in calibrating a hot-wire probe, in constructing a simple linearizer circuit of high accuracy, and in linearization by means of a computer.
Studying turbulence using direct numerical simulation: 1987 Center for Turbulence Research NASA Ames/Stanford Summer Programme
Authors: Hunt J. C. R.
Published: April 2006

This paper is an account of a summer programme for the study of the ideas and models of turbulent flows, using the results of direct numerical stimulations of the Navier-Stokes equations. These results had been obtained on the computers and stored as accessible databases at the Center for Turbulence Research (CTR) of NASA Ames Research Center and Stanford University. At this first summer programme, some 32 visiting researchers joined those at the CTR to test hypotheses and models in five aspects of turbulence research: turbulence decomposition, bifurcation and chaos; two-point closure (or k-space) modelling; structure of turbulent boundary layers; Reynolds-stress modelling; scalar transport and reacting flows.

A number of new results emerged including: computation of space and space-time correlations in isotropic turbulence can be related to each other and modelled in terms of the advection of small scales by large-scale motion; the wall layer in turbulent boundary layers is dominated by shear layers which protrude into the outer layers, and have long lifetimes; some aspects of the ejection mechanism for these layers can be described in terms of the two-dimensional finite-amplitude Navier-Stokes solutions; a self-similar form of the two-point, cross-correlation data of the turbulence in boundary layers (when normalized by the r.m.s. value at the furthest point from the wall) shows how both the blocking of eddies by the wall and straining by the mean shear control the lengthscales; the intercomponent transfer (pressure-strain) is highly localized in space, usually in regions of concentrated vorticity; conditioned pressure gradients are linear in the conditioning of velocity and independent of vorticity in homogeneous shear flow; some features of coherent structures in the boundary layer are similar to experimental measurements of structures in mixing-layers, jets and wakes.

The availability of comprehensive velocity and pressure data certainly helps the investigation of concepts and models. But a striking feature of the summer programme was the diversity of interpretation of the same computed velocity fields. There are few signs of any convergence in turbulence research! But with new computational facilities the divergent approaches can at least be related to each other.
On vortex formation from a cylinder. Part 1. The initial instability
Authors: Unal M. F. , Rockwell D.
Published: April 2006

Vortex shedding from a circular cylinder is examined over a tenfold range of Reynolds number, 440 ≤ Re ≤ 5040. The shear layer separating from the cylinder shows, to varying degrees, an exponential variation of fluctuating kinetic energy with distance downstream of the cylinder. The characteristics of this unsteady shear layer are interpreted within the context of an absolute instability of the near wake. At the trailing-end of the cylinder, the fluctuation amplitude of the instability correlates well with previously measured values of mean base pressure. Moreover, this amplitude follows the visualized vortex formation length as Reynolds number varies. There is a drastic decrease in this near-wake fluctuation amplitude in the lower range of Reynolds number and a rapid increase at higher Reynolds number. These trends are addressed relative to the present, as well as previous, observations.
The slow dripping of a viscous fluid
Authors: Wilson S. D. R.
Published: April 2006

The problem considered is the determination of the mass of the drops which break away when a viscous liquid drips slowly out of a narrow vertical tube. A simple one-dimensional theory of the unsteady extension of a viscous thread under its own weight is given, which holds when viscosity, capillarity and gravity are important but inertia is negligible. A comparison with experiment is given. There are several systematic errors, the most important of which are associated with detailed behaviour at the pipe exit where die-swell and wetting are difficult to assess. With due allowance for these errors, agreement is fairly good.
A laboratory study of the minimum wind speed for wind wave generation
Authors: Kahma Kimmo K. , Donelan Mark A.
Published: April 2006

The minimum wind speed for wind wave generation has been investigated in a laboratory wind-wave flume using a sensitive slope gauge to measure the initial wavelets about 10 μm high. The growth at very low wind speeds was higher than predicted by the viscous shear-flow instability theory. Assuming that the growth is exponential, the inception wind speed at which the growth rate becomes positive can be defined. It occurred at (friction velocity)u*≈ 2 cm/s, somewhat lower than theu*≈ 4–5 cm/s predicted by shear-flow instability theory. However, the observed growth rates were close to the theory at higher wind speeds when the waves were higher than 1 mm. The effect of temperature on the wind speed at which the waves become readily visible is shown to be appreciable and in keeping with the temperature dependent viscous damping. Other sources of growth are discussed. Our estimates show that the Phillips resonance mechanism might be sufficiently effective to generate the observed growth at very low wind speeds.