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Multipoint Aerodynamic Shape Optimization Investigations of the Common Research Model Wing

TitleMultipoint Aerodynamic Shape Optimization Investigations of the Common Research Model Wing
Publication TypeConference Papers
Year of Publication2014
AuthorsKenway, GKW, Martins, JRRA
Conference Name2015 AIAA SciTech
Date Published01/2015
Conference LocationKissimmee, FL
Aerodynamic shape optimization of wings in transonic flow is an inherently challenging problem.
In addition to the high computational cost of solving the Reynolds-averaged Navier–Stokes (RANS)
equations, there is a complex interdependence between the cross-sectional shape, wave drag and
viscous effects. Furthermore, it is necessary to perform multipoint optimizations to ensure good performance
for a range of flight conditions. The choice of which flight conditions should be considered
in the multipoint optimization, and how many points should be considered is still not well understood.
We address this issue by solving a series of six benchmark optimizations developed by the
Aerodynamic Shape Optimization Discussion Group. These optimization cases include a single point
optimization, four 3-point optimizations, and a 9-point optimization. The optimization consists in
minimizing the weighted drag coefficient subject to lift, moment, thickness, and volume constraints.
The optimizations are performed with respect to 768 shape design variables, and an angle of attack for
each flight condition. The single point optimization was able to achieve a 7.5% drag reduction relative
to the initial design, but it exhibits poor off-design performance. All optimized designs were compared
using a contour plot of ML/cD to evaluate the wing performance over the complete transonic flight
operating envelope. Each of the four 3-point optimizations successfully mitigated the poor off-design
performance of the single point design. However, the 3-point optimization with widely spaced Mach
numbers yielded a much more complexML/cD contour with two distinct local maxima. Finally, the
9-point optimization yielded the most robust off-design performance.
Citation Key1194