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Article
Publication date: 11 July 2024

Francisco Sánchez-Moreno, David MacManus, Fernando Tejero, Josep Hueso-Rebassa and Christopher Sheaf

The decrease in specific thrust achieved by Ultra-High Bypass Ratio (UHBPR) aero-engines allows for a reduction in specific fuel consumption. However, the typical associated…

89

Abstract

Purpose

The decrease in specific thrust achieved by Ultra-High Bypass Ratio (UHBPR) aero-engines allows for a reduction in specific fuel consumption. However, the typical associated larger fan size might increase the nacelle drag, weight and the detrimental interference effects with the airframe. Consequently, the benefits from the new UHBPR aero-engine cycle may be eroded. This paper aims to evaluate the potential improvement in the aerodynamic performance of compact nacelles for installed aero-engine configuration.

Design/methodology/approach

Drooped and scarfed non-axisymmetric compact and conventional nacelle designs were down selected from a multi-point CFD-based optimisation. These were computationally assessed at a set of installation positions on a contemporary wide-body, twin-engine transonic aircraft. Both cruise and off-design conditions were evaluated. A thrust and drag accounting method was applied to evaluate different aircraft, powerplant and nacelle performance metrics.

Findings

The aircraft with the compact nacelle configuration installed at a typical installation position provided a reduction in aircraft cruise fuel consumption of 0.44% relative to the conventional architecture. However, at the same installation position, the compact design exhibits a large flow separation at windmilling conditions that is translated into an overall aircraft drag penalty of approximately 5.6% of the standard cruise net thrust. Additionally, the interference effects of a compact nacelle are more sensitive to deviations in mass flow capture ratio (MFCR) from the nominal windmilling diversion condition.

Originality/value

This work provides a comprehensive analysis of not only the performance but also the aerodynamics at an aircraft level of compact nacelles compared to conventional configurations for a range of installations positions at cruise. Additionally, the engine-airframe integration aerodynamics is assessed at an off-design windmilling condition which constitutes a key novelty of this paper.

Details

Aircraft Engineering and Aerospace Technology, vol. 96 no. 6
Type: Research Article
ISSN: 1748-8842

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Article
Publication date: 9 December 2022

Fernando Tejero, David MacManus, Jesús Matesanz García, Avery Swarthout and Christopher Sheaf

Relative to in-service aero-engines, the bypass ratio of future civil architectures may increase further. If traditional design rules are applied to these new configurations and…

265

Abstract

Purpose

Relative to in-service aero-engines, the bypass ratio of future civil architectures may increase further. If traditional design rules are applied to these new configurations and the housing components are scaled, then it is expected that the overall weight, nacelle drag and the effects of aircraft integration will increase. For this reason, the next generation of civil turbofan engines may use compact nacelles to maximise the benefits from the new engine cycles. The purpose of this paper is to present a multi-level design and optimisation process for future civil aero-engines.

Design/methodology/approach

An initial set of multi-point, multi-objective optimisations for axisymmetric configurations are carried out to identify the trade-off between intake and fancowl bulk parameters of highlight radius and nacelle length on nacelle drag. Having identified the likely optimal part of the design space, a set of computationally expensive optimisations for three-dimensional non-axisymmetric configurations is performed. The process includes cruise- and windmilling-type operating conditions to ensure aerodynamic robustness of the downselected configurations.

Findings

Relative to a conventional aero-engine nacelle, the developed process yielded a compact aero-engine configuration with mid-cruise drag reduction of approximately 1.6% of the nominal standard net thrust.

Originality/value

The multi-point, multi-objective optimisation is carried out with a mixture of regression and classification functions to ensure aerodynamic robustness of the downselected configurations. The developed computational approach enables the optimisation of future civil aero-engine nacelles that target a reduction of the overall fuel consumption.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 33 no. 4
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 30 September 2022

Fernando Tejero, David MacManus, Josep Hueso-Rebassa, Francisco Sanchez-Moreno, Ioannis Goulos and Christopher Sheaf

Aerodynamic shape optimisation is complex because of the high dimensionality of the problem, the associated non-linearity and its large computational cost. These three aspects…

172

Abstract

Purpose

Aerodynamic shape optimisation is complex because of the high dimensionality of the problem, the associated non-linearity and its large computational cost. These three aspects have an impact on the overall time of the design process. To overcome these challenges, this paper aims to develop a method for transonic aerodynamic design with dimensionality reduction and multifidelity techniques.

Design/methodology/approach

The developed methodology is used for the optimisation of an installed civil ultra-high bypass ratio aero-engine nacelle. As such, the effects of airframe-engine integration are considered during the optimisation routine. The active subspace method is applied to reduce the dimensionality of the problem from 32 to 2 design variables with a database compiled with Euler computational fluid dynamics (CFD) calculations. In the reduced dimensional space, a co-Kriging model is built to combine Euler lower-fidelity and Reynolds-averaged Navier stokes higher-fidelity CFD evaluations.

Findings

Relative to a baseline aero-engine nacelle derived from an isolated optimisation process, the proposed method yielded a non-axisymmetric nacelle configuration with an increment in net vehicle force of 0.65% of the nominal standard net thrust.

Originality/value

This work investigates the viability of CFD optimisation through a combination of dimensionality reduction and multifidelity method and demonstrates that the developed methodology enables the optimisation of complex aerodynamic problems.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 33 no. 4
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 25 July 2024

Francisco Sánchez-Moreno, David MacManus, Fernando Tejero and Christopher Sheaf

Aerodynamic shape optimisation is a complex problem usually governed by transonic non-linear aerodynamics, a high dimensional design space and high computational cost…

44

Abstract

Purpose

Aerodynamic shape optimisation is a complex problem usually governed by transonic non-linear aerodynamics, a high dimensional design space and high computational cost. Consequently, the use of a numerical simulation approach can become prohibitive for some applications. This paper aims to propose a computationally efficient multi-fidelity method for the optimisation of two-dimensional axisymmetric aero-engine nacelles.

Design/methodology/approach

The nacelle optimisation approach combines a gradient-free algorithm with a multi-fidelity surrogate model. Machine learning based on artificial neural networks (ANN) is used as the modelling technique because of its ability to handle non-linear behaviour. The multi-fidelity method combines Reynolds-averaged Navier Stokes and Euler CFD calculations as high- and low-fidelity, respectively.

Findings

Ratios of low- and high-fidelity training samples to degrees of freedom of nLF/nDOFs = 50 and nHF/nDOFs = 12.5 provided a surrogate model with a root mean squared error less than 5% and a similar convergence to the optimal design space when compared with the equivalent CFD-in-the-loop optimisation. Similar nacelle geometries and aerodynamic flow topologies were obtained for down-selected designs with a reduction of 92% in the computational cost. This highlights the potential benefits of this multi-fidelity approach for aerodynamic optimisation within a preliminary design stage.

Originality/value

The application of a multi-fidelity technique based on ANN to the aerodynamic shape optimisation problem of isolated nacelles is the key novelty of this work. The multi-fidelity aspect of the method advances current practices based on single-fidelity surrogate models and offers further reductions in computational cost to meet industrial design timescales. Additionally, guidelines in terms of low- and high-fidelity sample sizes relative to the number of design variables have been established.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 34 no. 9
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 February 1973

R.A. Christophers

The disadvantages of notifying libraries' holdings to Regional Library Bureaux by means of BNB numbers are described. Since mid‐1970 an ISBN‐based notification system has been…

29

Abstract

The disadvantages of notifying libraries' holdings to Regional Library Bureaux by means of BNB numbers are described. Since mid‐1970 an ISBN‐based notification system has been used by LASER: member libraries notify holdings as lists of ISBNs which are key‐punched and used to update a master magnetic tape record. The LASER location index is output as COM film every two months. The technical and administrative features of the extension of this system to other Regional Bureaux are described.

Details

Program, vol. 7 no. 2
Type: Research Article
ISSN: 0033-0337

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Article
Publication date: 1 October 2020

Christopher Scott Thompson

This paper aims to reintroduce to proponents of natural disaster readiness worldwide the history and content of the most renowned tsunami mitigation tale in Japan, “Inamura no Hi”…

285

Abstract

Purpose

This paper aims to reintroduce to proponents of natural disaster readiness worldwide the history and content of the most renowned tsunami mitigation tale in Japan, “Inamura no Hi” (“The Rice Bale Fire”) for the purpose of reconnecting with its many virtues that have made it a cross-cultural pedagogical catalyst for tsunami preparedness education. At a time in the planet's history when global warming mitigation and pandemic advertence in a milieu in which equity, diversity and human rights are highly valued, the insights it contains pertaining to tsunami preparedness, plot design and the politics of its popularity make it particularly instructive.

Design/methodology/approach

The study used methods, approaches and techniques prevalent in cultural anthropology, i.e. primary texts, historical analysis, linguistic natural hazard preparedness education theory and ethnographic insights to assess how and why “Inamura no Hi” (“The Rice Bale Fire”) has come to be used so broadly on an international scale as a tsunami preparedness teaching tool and the politics involved in this process.

Findings

The study revealed that the cross-cultural relevance of “Inamura no Hi” (“The Rice Bale Fire”) is related to its unique authorship and development which has cultivated in it three qualities highly compatible with effective disaster mitigation at the international level. These are the simplicity of its message, the practical advice it dispenses and the universally agreeable morality it supports. However, the way in which the Japanese Government has promoted this story does not effectively encourage equity, diversity, or a respect for human rights as a major facilitator of preparedness among the many nations like itself in the region and in the world that are vulnerable to natural hazards.

Research limitations/implications

The main limitations of the study are that it is based on a historic investigation of the origins of “Inamura no Hi” (“The Rice Bale Fire”) using materials in English and Japanese, a genealogical interpretation of the story using approaches prevalent in translation studies and a qualitative analysis of historical uses of the story, all of which are difficult to quantify. Since the study seeks to find social and cultural patterns in the relevant material presented, the analysis reflects a subjectivity common in all social scientific studies of this kind.

Practical implications

Educating its readers about tsunami preparedness is one of the most important functions of this paper. The study confirms that “Inamura no Hi” (“The Rice Bale Fire”) provides Japanese and non-Japanese alike with the opportunity to envision and construct a customized culturally specific sense of tsunami readiness by harnessing this dynamic. For Japanese, the story provides a chance to contemplate an astute view of Japanese-style tsunami management from the viewpoint of an outsider who became a well-respected citizen. For non-Japanese, the story offers an opportunity to be reflexive about tsunami readiness based on a cross-culturally adaptable template that Hamaguchi's protagonist Gohei provides.

Social implications

Pedagogically speaking, “Inamura no Hi” (“The Rice Bale Fire”) makes the most sense when regarded as a starting point for preparing for any natural disaster anywhere. The story reminds us that the most educational, globally relevant tsunami preparedness narratives are those that complement and extend the latest of what the world knows about these destructive ocean waves to keep vulnerable citizens safe and alive. This study reveals that as important as the story is the politics of its delivery to provide the best first line of defense against tsunami amnesia which in Japan and many other countries has historically taken far too many lives.

Originality/value

The paper argues that “Inamura no Hi” (“The Rice Bale Fire”) is an example of a tsunami preparedness story that contains a variety of insights that continue to contribute to tsunami awareness education cross culturally that must not be underestimated. However, the way it is currently promoted by the Japanese Government needs to be improved, so that more representatives from more countries involved in tsunami preparedness and natural hazard readiness worldwide can benefit. These are insights not accessible by a researcher who is not bilingual in English and Japanese; thus, by using an ethnographic approach and participant observation utilizing both languages as part of long-term fieldwork, the researcher can gain these insights.

Details

Disaster Prevention and Management: An International Journal, vol. 30 no. 2
Type: Research Article
ISSN: 0965-3562

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Article
Publication date: 1 February 1941

WHILE so many things are happening and are expected to happen in the war field, the attention that libraries receive is to be watched carefully. One could hope, so far as their…

23

Abstract

WHILE so many things are happening and are expected to happen in the war field, the attention that libraries receive is to be watched carefully. One could hope, so far as their finances are concerned, that they might be treated as last year but otherwise forgotten. This is most unlikely, and the reports that reach us show that we are facing the most critical days since 1919. There is, however, this difference; during the last war, the penny‐rate limit seemed to exclude all recovery from the drastic cuts then made. Hereafter such recovery can be as rapid as the value of our work persuades our authorities to make it—that is, if and when they have the means. The crisis for many of the towns which have been “coventrated” or otherwise heavily attacked must be severe. The destruction of shopping streets must mean a substantial loss of rateable value for the time being. At the same time all rate‐supported services must continue, and these continue to increase in cost. For some towns it may be difficult to sustain some public services at all.

Details

New Library World, vol. 43 no. 7
Type: Research Article
ISSN: 0307-4803

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Article
Publication date: 1 March 1914

IN the death of Mr. JAMES DUFF BROWN, the library profession loses one of its most striking personalities and librarianship its most powerful influence for progress. Any attempt…

37

Abstract

IN the death of Mr. JAMES DUFF BROWN, the library profession loses one of its most striking personalities and librarianship its most powerful influence for progress. Any attempt at present to estimate the extent of his influence upon the modern public library must necessarily be inadequate, because not only are some of the movements he started only beginning to gather force, but his retiring nature made him refrain from labelling many things as his own. With the possible reservation that he was unable to do himself justice on the platform, he was the ideal born public librarian. As an organiser and teacher of librarianship, as a keen and discerning student and critic of tendencies, methods and results, and as an expounder of professional knowledge through the medium of the written page, he was without an equal. Like all pioneers and men of strong opinions, he did not make only friends ; but he had world‐wide friendships, and he forced the attention and respect of all library workers. On another page of this issue an old friend and one‐time colleague of his gives a brief outline of his life and works, and we need not do the same again here. But as his successors in the editorship of THE LIBRARY WORLD, which he founded and edited until a year or two ago, we cannot refrain from adding our tribute to his memory. Representing the best type of efficiency and progress in librarianship, he was a real friend and teacher, and his death leaves a sad gap in our ranks.

Details

New Library World, vol. 16 no. 9
Type: Research Article
ISSN: 0307-4803

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Article
Publication date: 1 December 1907

THE enterprise of two London newspapers, the Tribune (for the second time) and the Daily Chronicle, in organizing exhibitions of books affords a convenient excuse for once again…

33

Abstract

THE enterprise of two London newspapers, the Tribune (for the second time) and the Daily Chronicle, in organizing exhibitions of books affords a convenient excuse for once again bringing forward proposals for a more permanent exhibition. On many occasions during the past twenty years the writer has made suggestions for the establishment of a central book bazaar, to which every kind of book‐buyer could resort in order to see and handle the latest literature on every subject. An experiment on wrong lines was made by the Library Bureau about fifteen years ago, but here, as in the exhibitions above mentioned, the arrangement was radically bad. Visiting the Daily Chronicle show in company with other librarians, and taking careful note of the planning, one was struck by the inutility of having the books arranged by publishers and not by subjects. Not one visitor in a hundred cares twopence whether books on electricity, biography, history, travel, or even fairy tales, are issued by Longmans, Heinemann, Macmillan, Dent or any other firm. What everyone wants to see is all the recent and latest books on definite subjects collected together in one place. The arrangements at the Chronicle and Tribune shows are just a jumble of old and new books placed in show‐cases by publishers' names, similar to the abortive exhibition held years ago in Bloomsbury Street. What the book‐buyer wants is not a miscellaneous assemblage of books of all periods, from 1877 to date, arranged in an artistic show‐case and placed in charge of a polite youth who only knows his own books—and not too much about them—but a properly classified and arranged collection of the newest books only, which could be expounded by a few experts versed in literature and bibliography. What is the use of salesmen in an exhibition where books are not sold outright? If these exhibitions were strictly limited to the newest books only, there would be much less need for salesmen to be retained as amateur detectives. Another decided blemish on such an exhibition is the absence of a general catalogue. Imagine any exhibition on business lines in which visitors are expected to cart away a load of catalogues issued separately by the various exhibitors and all on entirely different plans of arrangement! The British publisher in nearly everything he does is one of the most hopeless Conservatives in existence. He will not try anything which has not been done by his grandfather or someone even more remote, so that publishing methods remain crystallized almost on eighteenth century lines. The proposal about to be made is perhaps far too revolutionary for the careful consideration of present‐day publishers, but it is made in the sincere hope that it may one day be realized. It has been made before without any definite details, but its general lines have been discussed among librarians for years past.

Details

New Library World, vol. 10 no. 6
Type: Research Article
ISSN: 0307-4803

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Article
Publication date: 1 January 2002

Amy Wong and Amrik Sohal

Attempts to examine the concepts of trust and commitment, on two levels of retail relationships: the salesperson level as well as the store level, and test their impact on…

14033

Abstract

Attempts to examine the concepts of trust and commitment, on two levels of retail relationships: the salesperson level as well as the store level, and test their impact on relationship quality. Based on a review of the literature, a conceptual model has been developed that links trust and commitment to relationship quality. A number of research hypotheses have been formulated to examine the relationships proposed. The paper presents the model developed and discusses some empirical findings from a survey of 1,261 shoppers in a departmental store setting in Victoria, Australia. In particular, the two levels of relationships (salesperson and store level) are examined from the customer’s perspective, using structural equation modelling (LISREL VIII). Concludes with a discussion of the implications of the study and provides directions for future research.

Details

International Journal of Retail & Distribution Management, vol. 30 no. 1
Type: Research Article
ISSN: 0959-0552

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