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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2015, Vol. 36 ›› Issue (5): 1480-1490.doi: 10.7527/S1000-6893.2014.0331

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

Parameterization and grid deformation techniques for flying-wing aerodynamic optimization

TANG Jing1, DENG Youqi2, MA Mingsheng1,2, LI Bin2   

  1. 1. School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China;
    2. Computational Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang 621000, China
  • Received:2014-07-16 Revised:2014-12-01 Online:2015-05-15 Published:2014-12-11

Abstract:

Geometry shape parameterization and grid deformation techniques are two key issues for aerodynamic shape optimization of aircraft by CFD. The non-uniform rational B-splines (NURBS)-based free-form deformation (NFFD), which is universal for arbitrary representation of geometry, and the dynamic grid technique based on distance weighted function (DWF), which is independent from grid topology and fast on calculation, are widely used for shape optimization. In this paper, the NFFD technique is introduced in detail and the Newton iteration algorithms for inverse local coordinates calculation are developed. The DWF is improved (IDWF) to satisfy larger range grid deformation by increasing the stiffness of grid cells near surface. The parallel implementation algorithms for both techniques are designed and introduced in detail. With an optimization solver based on gradient calculated by discrete adjoint method, the standard flying-wing airfoil EH1590 is inversely designed form the initial airfoil NACA0012, and the ratio of lift and drag is optimized and increased by 18% for a whole flying-wing aircraft in a single design state. The result indicates that for flying-wing aerodynamic shape optimization, the NFFD technique is sufficient for shape parameterization and IDWF technique is efficient for grid deformation.

Key words: shape parameterization, free-form deformation, distance weighted function, dynamic grid, flying-wing, shape optimization

CLC Number: