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taper ratio etc. could all be tested and innovative
designs analyzed (Fig. 21). After that, Fluent
could be used for fine-tuning and verification of
the different winglets at transonic speeds. With
this process and using more powerful CFD
hardware, it was possible to analyze tens of
configurations in one month, resulting in
improved designs and new innovative
configurations which could result in more
attractive options contemplating structural and
manufacturing constraints. A key aspect was the
combination of skilled CAD work, low fidelity
analysis for configuration parametric analysis
and high fidelity transonic tailoring using
Fluent’s capabilities. As a result, the Embraer
195 program could have different options for
the winglet design in reduced time.
Fig. 21 – A low aspect-ratio winglets were also
investigated to the Embraer 195.
Concluding Remarks
The present work showed that winglets are
becoming an important and common instrument
to achieve performance improvements in the
present highly competitive aircraft market.
Various aspects affecting the design of
winglets were described and highlighted,
ranging from airfoil characteristics to the shape
and importance of correctly designing the
transition surface between the wing and the
winglet.
Embraer has successfully designed and
installed winglets for several of its products
with impressive results. For this task, CFD tools
proved to be mandatory for an efficient design
of winglets for transonic aircraft configurations.
Extensive wind-tunnel testing and CFD has
enabling the design of efficient winglets
The experience gathered by Embraer
and the widespread use of winglets in new
aircraft designs allow to conclude that the old
question of the feasibility of winglet adoption
by designers is no longer valid. Instead a new
issue concerning the choice of the best wingtip
device configuration is currently in place.
References
1. Dess, P., Stowell, M., "737-800
Winglet Integration," Aicraft Congress and
Exhibition, paper No. 2001-01-2989, California,
USA, 2001.
2. De Mattos, B. S., "Winglets da
Embraer," Engenharia Automotiva e
Aeroespacial Magazine, SAE, 2nd Year, No. 7.
3. FLUENT 5.3 User’s Guide, Vols. 1-4.
FLUENT Incorporated, Lebanon, New
Hampshire, USA.
4. Boeing Aero Magazine, No. 17,
January 2002.
5. “Engineering Methods in Aerodynamic
Analysis and Design of Aircraft,” AGARD R-
783 Report, January 1992.
6. Richard T. Whitcomb, “A Design
Approach and Selected Wind-Tunnel Results at
High Subsonic Speeds for Wing-Tip Mounted
Winglets,” NASA TN D-8260, July 1976.
7. Drela, M., "Newton Solution of
Coupled Viscous/Inviscid Multielement Airfoil
Flows," AIAA Paper 90-1470, 1990.
8. Drela, M., and Giles, M. B., “Viscous-
Inviscid Analysis of Transonic and Low
Reynolds Number Airfoils,” AIAA Journal,
Vol. 25, No. 10, 1987, pp. 1347-1355.
9. Flight Safety Digest, October 1998.
10. Drela, M., “XFOIL: An Analysis and
Design System for Low Reynolds Number
Airfoils,“Conference on Low Reynolds Number
Airfoil Aerodynamics, University of Notre
Dame, June 1989.
Building a specialized static analyzer
The Astr´ee experience
Antoine Min´e
CNRS, ´Ecole Normale Sup´erieure
Security and Reliability of Software Systems
12 December 2008
Antoine Min´e Building a specialized static analyzer p. 1 / 112
Introduction
Analyse Statique Temps R´EEl
check statically for the absence of run-time errors (RTE)
on synchronous reactive codes, in a subset of C
fast ('50 KLoc/h), precise (aims at 0 alarms) and sound
Development team
CNRS / ENS
(B. Blanchet), P. Cousot, R. Cousot, L. Mauborgne,
(D. Monniaux), J. Feret, A. Min´e, X. Rival
http://www.astree.ens.fr
Antoine Min´e Building a specialized static analyzer p. 2 / 112
The Astr´ee analyzer
academic tool, with industrial applications in mind
110 000 lines of OCaml
Time-line
Nov. 2001 Astr´ee project starts
Nov. 2003 primary control software of the Airbus A340
analyzed
proof of the absence of RTE
Jan. 2004 start working on Airbus A380
(while A380 development in progress)
Apr. 2005 maiden flight of the A380
proof of the absence of RTE (for current version)
Sep. 2008 study on applicability to space software
Antoine Min´e Building a specialized static analyzer p. 3 / 112
　
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