Cédric Decrocq, Bastien Martinez, Marie Albisser, Simona Dobre, Patrick Gnemmi, Yannick Bailly and Jean-Claude Roy
The present paper deals with weapon aerodynamics and aims to describe preliminary studies that were conducted for developing the next generation of long-range guided ammunition…
Abstract
Purpose
The present paper deals with weapon aerodynamics and aims to describe preliminary studies that were conducted for developing the next generation of long-range guided ammunition. Over history, ballistic research scientists were constantly investigating new artillery systems capable of overcoming limitations of range, accuracy and manoeuvrability. While futuristic technologies are increasingly under development, numerous issues concerning current powdered systems still need to be addressed. In this context, the present work deals with the design and the optimization of a new concept of long-range projectile with regard to multidisciplinary fields, including flight scenario, steering strategy, mechanical actuators or size of payload.
Design/methodology/approach
Investigations are conducted for configurations that combine existing full calibre 155 mm guided artillery shell with a set of lifting surfaces. As the capability of the ammunition highly depends on lifting surfaces in terms of number, shape or position, a parametric study has to be conducted for determining the best aerodynamic architecture. To speed-up this process, initial estimations are conducted thanks to low computational cost methods suitable for preliminary design requirements, in terms of time, accuracy and flexibility. The WASP code (Wing-Aerodynamic-eStimation-for-Projectiles) has been developed for rapidly predicting aerodynamic coefficients (static and dynamic) of a set of lifting surfaces fitted on a projectile fuselage, as a function of geometry and flight conditions, up to transonic velocities.
Findings
In the present study, WASP predictions at Mach 0.7 of both normal force and pitching moment coefficients are assessed for two configurations.
Originality/value
Analysis is conducted by gathering results from WASP, computational-fluid-dynamics (CFD) simulations, wind-tunnel experiments and free-flight tests. Obtained results demonstrate the ability of WASP code to be used for preliminary design steps.
Details
Keywords
Laurène Muller, Michel Libsig, Yannick Bailly and Jean-Claude Roy
This paper aims to propose a dedicated measurement methodology able to simultaneously determine the stability derivative Cmα and the pitch damping coefficient sum Cmq + Cmα in a…
Abstract
Purpose
This paper aims to propose a dedicated measurement methodology able to simultaneously determine the stability derivative Cmα and the pitch damping coefficient sum Cmq + Cmα in a wind tunnel using a single and almost non-intrusive metrological setup called MiRo.
Design/methodology/approach
To assess the MiRo method’s reliability, repeatability and accuracy, the measurements obtained with this technique are compared to other sources like aerodynamic balance measurements, alternative wind tunnel measurements, Ludwieg tube measurements, free-flight measurements and computational fluid dynamics (CFD) simulations. Two different numerical approaches are compared and used to validate the MiRo method. The first numerical method forces the projectile to describe a pure oscillation motion with small amplitude along the pitch axis during a rectilinear flight, whereas the second numerical approach couples the one degrees of freedom simulation motion equations with CFD methods.
Findings
MiRo, a novel and almost non-intrusive technique for dynamic wind tunnel measurements, has been validated by comparison with five other experimental and numerical methodologies. Despite two completely different approaches, both numerical methods give almost identical results and show that the holding system has nearly no impact on the dynamic aerodynamic coefficients. Therefore, it could be assessed that the attitude of MiRo model in the wind tunnel is very close to the free-flight one.
Originality/value
The MiRo method allows studying the attitude of a projectile in a wind tunnel with the least possible impact on the flow around a model.
Details
Keywords
This study offers a political risk prediction model that replicates a known political risk index on the basis of economic and political variables. The results show that the…
Abstract
This study offers a political risk prediction model that replicates a known political risk index on the basis of economic and political variables. The results show that the political risk is affected by the level of the United Nations human development index, the gross domestic savings as a percentage of gross domestic product, the labor force as a percentage of total population, the total expenditures on health and education as a percentage of gross domestic product and the level of the terms of trade.
The following list is a first attempt to catalogue and describe systematically the British Museum's extensive holdings of early opera librettos and related plays. The great…
Abstract
The following list is a first attempt to catalogue and describe systematically the British Museum's extensive holdings of early opera librettos and related plays. The great importance of these unpretentious booklets as supplementary and, more often than not, even primary sources for the history and bibliography of dramatic music, besides or instead of the scores, was already clearly recognized in the eighteenth century by Dr. Burney and other scholars. But it is only since 1914, the year in which O. G. T. Sonneck's Library of Congress Catalogue of opera librettos printed before 1800 appeared, that their documentary value could to any greater extent be put to general use in international musicological research. A similar bibliography of the British Museum librettos, while naturally duplicating many Washington entries, would produce a great number of additional tides, not a few of them otherwise unrecorded; it would provide the musical scholar with the key to a collection unequalled elsewhere in Europe, which owing to the peculiar nature of the material is not easily accessible by means of the General Catalogue.
Ahmad Shawan, Jean-Claude Léon, Gilles Foucault and Lionel Fine
Preparing digital mock-ups (DMUs) for finite element analyses (FEAs) is currently a long and tedious task requiring many interactive CAD model transformations. Functional…
Abstract
Purpose
Preparing digital mock-ups (DMUs) for finite element analyses (FEAs) is currently a long and tedious task requiring many interactive CAD model transformations. Functional information about components appears to be very useful to speed this preparation process. The purpose of this paper is to shows how DMU components can be automatically enriched with some functional information.
Design/methodology/approach
DMUs are widespread and stand as reference model for product description. However, DMUs produced by industrial CAD systems essentially contain geometric models, which lead to tedious preparation of finite element Models (FEMs). Analysis and reasoning approaches are developed to automatically enrich DMUs with functional and kinematic properties. Indeed, geometric interfaces between components form a key starting point to analyze their behaviors under reference states. This is a first stage in a reasoning process to progressively identify mechanical, kinematic as well as functional properties of components.
Findings
Inferred semantics adds up to the pure geometric representation provided by a DMU and produce also geometrically structured components. Functional information connected to a structured geometric model of a component significantly improves FEM preparation and increases its robustness because idealizations can take place using components’ functions and components’ structure helps defining sub-domains of FEMs.
Research limitations/implications
Future research will carry on improving algorithms for geometric interfaces identification, processing a wider range of component functions, which will contribute to a formalization of the concept of functional consistency of a DMU.
Originality/value
Simulation engineers benefit from this automated enrichment of DMUs with functional information to speed up the preparation of FEAs of large assemblies.
Details
Keywords
Tanusree Dutta, Subhadip Roy, Soumya Sarkar and Sudipa Nag
This study aims to investigate the nuances of celebrity spokesperson effectiveness in business-to-business (B2B) advertising. Specifically, the study addresses the question of…
Abstract
Purpose
This study aims to investigate the nuances of celebrity spokesperson effectiveness in business-to-business (B2B) advertising. Specifically, the study addresses the question of endorser effectiveness in the presence of product complexity (high vs low) and how this effect is moderated by endorser gender. In addition, the study also explores whether the way an endorser is placed in the advertisement (product-facing vs audience-facing) would have differential effects on the buyer.
Design/methodology/approach
The present study uses experimental design to fulfil the study objectives. Two experiments are conducted (total n = 201) on employees in a purchasing role in organisations, with the dependent variable being dwell time (captured using an eye-tracking device).
Findings
Major findings indicate that celebrity gender has a moderating effect depending on the product complexity. Results also indicate a significant effect of how the celebrity is placed in the advertisement on the buyer.
Research limitations/implications
The findings emphasise the role of the spokesperson in B2B advertising using neuro-behavioural data. It also contributes to the theoretical nuances of spokesperson gender in B2B advertising and the role of kinesics in advertising using spokespersons.
Practical implications
The study provides guidelines on the choice of the spokesperson and their physical posture in the advertisement for B2B advertisers that may lead to communication effectiveness.
Originality/value
The present study is in a domain that is scarcely researched in B2B and adds novelty as it uses physiological data instead of self-reported measures.
Details
Keywords
The archives of François Perroux deposited at IMEC bear witness to the fact that he has devoted, beyond his scientific production, great energy to the most material aspects of…
Abstract
The archives of François Perroux deposited at IMEC bear witness to the fact that he has devoted, beyond his scientific production, great energy to the most material aspects of research: setting up and maintaining networks to publicize his work and that of other economists, either directly or through the institutes and the journals he headed; organize seminars and symposiums; take care of relations with colleagues and the press; create collections and journals; and so on.
In this chapter, we concentrate our attention on the archives relating to the management of the institutes, those attesting to the lines and themes of the producer’s research, and those concerning his important correspondence.
Thanks to the archives deposited at IMEC, it is possible to follow the development of the theoretical work of François Perroux by contextualizing it. They also show the itinerary of a Christian intellectual, whose attachment to social Catholicism constitutes a guiding thread and is reflected in all his activities. Finally, the archives illuminate his substantial role in the institutionalization of research in economics in the France of the twentieth century.