Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

20000061433 Pisa Univ., Dipartimento di Ingegneria Aerospaziale, Italy
Aerodynamics for MDO of an Innovative Configuration
Bernardini, G., Pisa Univ., Italy; Frediana, A., Pisa Univ., Italy; Morino, L., Rome Univ., Italy; Aerodynamic Design and Optimisation
of Flight Vehicles in a Concurrent Multi-Disciplinary Environment; June 2000, pp. 16-1 - 16-11; In English; See also
20000061419; Copyright Waived; Avail: CASI; A03, Hardcopy
A numerical methodology for the evaluation of aero-dynamic loads acting on a complex lifting configuration is presented.
The work is limited to the case of attached high-Reynolds number flows. A viscous/potential interaction technique is utilized to
take into account the effects of the viscosity. For the potential-flow analysis, a boundary element formulation is used; for simplicity,
only incompressible flows are examined. The theoretical basis of the present methodology is briefly described. Comparisons
with available, numerical and experimental results are included.
Author
Aerodynamic Loads; Numerical Analysis; Evaluation; Loads (Forces)
20000061443 Synaps Ingenieur-Gesellschaft m.b.H., Bremen, Germany
A Conceptual Design Methodology to Predict the Wave Drag of a Transonic Wing
Kribler, T., Synaps Ingenieur-Gesellschaft m.b.H., Germany; Aerodynamic Design and Optimisation of Flight Vehicles in a Concurrent
Multi-Disciplinary Environment; June 2000, pp. 27-1 - 27-8; In English; See also 20000061419; Copyright Waived; Avail:
CASI; A02, Hardcopy
A conceptual design methodology to predict the wave drag of a transonic wing for use within multidisciplinary aircraft design
was developed. to achieve this, a database of cross section designs optimized with respect to total drag was set up varying the
design parameters Ma, t/c, C(sub L) and Re. Mathematical formulations for the aerodynamic cross section characteristics total
drag, viscous drag and the local shock location were derived from the database as functions of the design parameters. The cross
section wave drag was then derived using these formulations. A locally infinite swept wing is assumed and simple sweep theory
using the shock sweep angle is used to transform the wave drag. The wave drag of a 3-D wing is predicted summing locally infinite
swept wing sections in spanwise direction. The achieved drag prediction is accurate enough for use within conceptual aircraft
design and predicts well the trends in wave drag development as a function of the design parameters Ma, t/c, C(sub L), Re and
the wing planform.
Author
Aircraft Design; Design Analysis; Wave Drag; Transonic Flow; Wing Planforms
20000061444 Florida Univ., Dept. of Aerospace Engineering, Mechanics and Engineering Science, Gainesville, FL USA
Airfoil and Wing Planform Optimization for Micro Air Vehicles
Sloan, J. G., Florida Univ., USA; Shyy, W., Florida Univ., USA; Haftka, R. T., Florida Univ., USA; Aerodynamic Design and
Optimisation of Flight Vehicles in a Concurrent Multi-Disciplinary Environment; June 2000, pp. 28-1 - 28-14; In English; See
also 20000061419; Copyright Waived; Avail: CASI; A03, Hardcopy
Low Reynolds number flight for micro air vehicles (microAVs) suffers from laminar separation resulting in reduced lift and
increased drag. The objective of the present work is to use the response surface methodology (RSM) to identify correlations
between the airfoil and the wing planform to facilitate a two-level optimization procedure in which an optimized airfoil and wing
planform are reached simultaneously. Several approaches have been considered in this work. A constant cross-section wing is
modeled with maximum camber, y(sub c), maximum thickness, y(sub t) and aspect ratio,AR, as design variables at two different
Reynolds numbers of 8.0 x 10(exp 4) and 2.0 x 10(exp 5). This is done to determine how the optimal airfoil may change for different
aspect ratios and Reynolds numbers. A variable cross-section wing defined by root camber and angle-of-attack and tip camber
and angle-of-attack is modeled in order to determine how the optimal airfoil may change from the root to the tip of the wing. Due
to the size restrictions on microAVs, a fixed-span approach is used to model an aircraft subject to the constraints of steady flight
with the aspect ratio and camber as design variables. This third approach balances trade-offs between wing area, aspect ratio, and
Reynolds number in determining the overall flight efficiency. Optimal airfoils exhibit characteristics which change little with wing
aspect ratio or location on the wing planform. There appears to be a trend of increasing optimal camber with decreasing Reynolds
number. While the optimal design seems to favor airfoils with minimum thickness and relatively modest camber of about 4 to 5%
of the chord, a higher camber may be a better choice if higher lift coefficient at minimum power is used as a design goal. Measurements
of both the global and the local response surface prediction accuracy combined with design space refinement help to assess
the reliability of the response surface approximations and optimal design predictions.
Author
Airfoils; Wing Planforms; Optimization; Camber; Design Analysis; Low Reynolds Number
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