High-fidelity aerodynamic shape optimization of modern transport wing using efficient hierarchical parameterization
Aerodynamic shape optimization technology is presented, using an efficient domain element parameterization approach. This provides a method that allows geometries to be parameterized at various levels, ranging from gross three-dimensional planform alterations to detailed local surface changes. Design parameters control the domain element point locations and, through efficient global interpolation functions, deform both the surface geometry and corresponding computational fluid dynamics volume mesh, in a fast, high quality, and robust fashion. This results in total independence from the mesh type (structured or unstructured), and optimization independence from the flow-solver is achieved by obtaining gradient information for an advanced gradient-based optimizer by finite-differences. Hence, the optimization tool can be used in conjunction with any flow-solver and/or mesh generator. Results have been presented recently for two-dimensional aerofoil cases, and shown impressive results; drag reductions of up to 45% were demonstrated using only 22 active design parameters. This paper presents the extension of these methods to three dimensions, with results for highly constrained optimization of a modern aircraft wing in transonic cruise. The optimization uses combined global and local parameters, giving 388 design variables, and produces a shock-free geometry with an 18% reduction in drag, with the added advantage of significantly reduced root moments. Copyright (C) 2009 John Wiley & Sons, Ltd.
aerodynamics cfd shape parameterization mesh deformation radial basis functions numerical optimization drag minimization