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1 – 10 of over 18000M. Kharati Koopaee, M.M. Alishahi and H. Emdad
The purpose of this paper is to discuss the capability of nonlinear frequency domain (NLFD) method in predicting surface pressure coefficient presented in the time domain in…
Abstract
Purpose
The purpose of this paper is to discuss the capability of nonlinear frequency domain (NLFD) method in predicting surface pressure coefficient presented in the time domain in unsteady transonic flows.
Design/methodology/approach
In this research, the solution and spatial operator are approximated by discrete form of Fourier transformation and resulting nonlinear equations are solved by use of pseudo‐spectral approach. Considered transonic flows involve different flow pattern on the airfoil surfaces. One of the test cases involves moving shocks on both lower and upper airfoil surfaces and in the two other test cases a moving shock occurs only on the upper surface.
Findings
Pressure distributions presented in the time domain using NLFD are compared with three test cases. Results show that NLFD predicts reasonable pressure distributions in time domain except in vicinity of shock positions. Although this method may predict unfair results near shock positions, however gives good estimates for global properties such as lift coefficient.
Originality/value
In the previous works on NLFD method, the flow field results have been limited to representing the pressure in the frequency domain or global coefficients such as lift coefficients. No details of pressure distributions in the time domain have been provided in such investigations. In this research, by presenting the pressure in the time domain, the conditions on which good pressure distributions are obtained are demonstrated.
SO much of the aircraft designer's attention has lately been diverted toward major developments such as supersonics, that there is some possibility of old‐established hazards like…
Abstract
SO much of the aircraft designer's attention has lately been diverted toward major developments such as supersonics, that there is some possibility of old‐established hazards like inadvertent stalls being forgotten. The only difference in these nowadays is that stalling speeds are generally higher and aircraft can strike the ground harder. There is perhaps therefore good reason for considering stalling hazards once again. In doing so, my remarks are confined to civil aircraft, partly because the safety of Service aircraft must often give way to their operational needs and partly because their accident statistics are not readily available for discussion.
In a volume of the Cornhill Magazine published in the year 1860 we have discovered an article entitled “Adulteration and its Remedy” which well deserves the attention of those…
Abstract
In a volume of the Cornhill Magazine published in the year 1860 we have discovered an article entitled “Adulteration and its Remedy” which well deserves the attention of those persons who imagine that we have made “wonderful progress” during the past half century and that the trade morality of to‐day is infinitely superior to the trade morality of the past. The unknown author of this article must have had a very clear appreciation of the nature of the gigantic evil upon which he wrote and of the character and probable effectiveness of the remedies to be applied. The adulteration of the period is described by him as a “strange, disgusting and poisonous demon” and while it is true that at the time, as shown by the revelations of the “Lancet Sanitary Commission,” there existed many forms of gross, disgusting and poisonous adulteration which are but rarely detected nowadays, our author's somewhat hyperbolic definition may still be regarded as applicable. For many of the grosser forms of adulteration prevalent fifty years ago were largely due to the ignorance of the adulterator. His prototype of the present day is no more troubled with moral scruples than he was. The dissemination and absorption of knowledge has not been accompanied, as some rabid “educationalists’ would have us believe, by any improvements in morality and virtue. The “faker ” of to‐day is merely a more skilful “faker” than his predecessor. He knows the value and makes full use of “expert” assistance, both scientific and legal, for the purpose of facilitating his escape—easy enough in any case—from what grip there is in that cranky and lumbering legislative machinery which is innocently supposed by the majority of people in this country to act as a sufficiently effective deterrent and repressant.
A methodology for implementing CAPM systems is described. Theresearch was motivated by evidence of dissatisfaction with theperformance of current systems, and the existence of no…
Abstract
A methodology for implementing CAPM systems is described. The research was motivated by evidence of dissatisfaction with the performance of current systems, and the existence of no generic methodology. A superposition process was employed. Areas of functional management were explored for sources of implementation methodologies and yielded a number of attributes for successful implementation. The emergent structure was then validated against field studies. The result, a methodology for improving control, is a three‐level hierarchy. The first level assesses the ability of the organisation to absorb change. The next considers the options for better control. The lowest level is concerned with implementation.
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David Clark, Kathryn McCann, Ken Morrice and Rex Taylor
In her recent discussion of women's incorporation into their husbands' employment Janet Finch produces a useful maxim for prospective wives:
The relationship between technology and strategic competitivenessis investigated. It is suggested that effective management of employeesand equipment can speed technological…
Abstract
The relationship between technology and strategic competitiveness is investigated. It is suggested that effective management of employees and equipment can speed technological advances to customers. However, managerial technological knowledge of the production process and technical aspects of equipment are of paramount importance for the successful implementation of any competitive strategy. Future areas of empirical investigation through testable propositions are suggested. Each proposition is a hypothesis and major study in itself, and it is hoped that future researchers will statistically analyse each proposition to confirm or deny its validity.
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THE design of a flying boat hull is a compromise between the usually conflicting requirements of good performance on the water and in flight. For example, from aerodynamic…
Abstract
THE design of a flying boat hull is a compromise between the usually conflicting requirements of good performance on the water and in flight. For example, from aerodynamic considerations the hull should be without discontinuities, while for low water resistance when planing, discontinuities are necessary in the form of steps and chines, the former to localise the wetted area to that portion providing lift, and the latter to keep the spray as low as possible. Again, though the minimum air drag results from symmetry about the longitudinal axis, it is usual to curve the tail of a hull upwards to give the tail plane sufficient water clearance.
RISING FUEL, service and maintenance prices have highlighted the need for strict cost monitoring of basic flying training, both in the military and commercial spheres. This…
Abstract
RISING FUEL, service and maintenance prices have highlighted the need for strict cost monitoring of basic flying training, both in the military and commercial spheres. This requirement has become particularly acute in the multi‐engined aircraft primary training context. The use of conventional twin‐engined aircraft for this purpose is expensive, both in terms of first cost and in operation. Moreover, the simulation of the “engine out” condition can, on occasions, prove hazardous.
The job redesign framework is implicit in the Quality Control Circle literature. It separates QCC′s from any policy considerations and creates grave distortions of view. The…
Abstract
The job redesign framework is implicit in the Quality Control Circle literature. It separates QCC′s from any policy considerations and creates grave distortions of view. The required broadened conception of American companies′ operations core can only be achieved if the languages of different disciplines merge to confront crucial management issues.
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The investigation arose in connection with fitting an autoslot system to the “Atlas,” and includes the development of a system of interconnecting the slot with the ailerons.