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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2022, Vol. 43 ›› Issue (12): 126132-126132.doi: 10.7527/S1000-6893.2021.26132

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

Discrete adjoint-based optimization approach for laminar flow wings

YANG Tihao1, WANG Yiwen2, WANG Yutong4, SHI Yayun3, ZHOU Zhu4   

  1. 1. School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China;
    2. Unmanned System Research Institute, Northwestern Polytechnical University, Xi'an 710072, China;
    3. School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, China;
    4. China Aerodynamics Research and Development Center, Mianyang 621000, China
  • Received:2021-07-20 Revised:2021-09-22 Published:2022-01-26
  • Supported by:
    National Natural Science Foundation of China (11902320, 12002284)

Abstract: Laminar flow is one of the key technologies in the future development of green aviation, while an efficient and reliable design optimization approach for problems with a large number of design variables is the key to promoting the industrial application of the laminar flow technique. Based on the high-fidelity RANS solver, and combined with the quasi-three-dimensional laminar boundary layer equation, Drela-Giles and C1 criteria, a transition prediction method, which can simultaneously capture Tollmien-Schlichting (TS) and Crossflow (CF) instabilities, is established. Comparison of the simulation results with typical wind tunnel and flight tests shows the reliability of the simulation approach. An accurate intermittency function is obtained by strictly interpolating the surface values to eliminate the numerical noise for the aerodynamic forces simulation. The coupled adjoint equation considering transition is derived accurately, and solved efficiently by combining the matrix-free technique, the chain rule, the hybrid reverse automatic differentiation, and the Coupled Krylov (CK) algorithm. Finally, the discrete adjoint-based laminar flow wings optimization method is built. The optimization of a wing-body configuration with typical characteristics of regional airliners demonstrates that the transition is effectively delayed, with 10.48% of the total drag reduced. The optimization results reveal that the gradient-based laminar flow wings optimization framework can deal with complex three-dimensional laminar flow wings optimization problems with multiple transition mechanisms.

Key words: discrete adjoint, laminar-turbulent transition, drag reduction, gradient-based optimization, streamwise transition, crossflow transition

CLC Number: