面向层流减阻设计的转捩预测方法研究

Transition prediction methods towards significant drag reduction via laminar flow technology

  • 摘要: 发展高效可靠的转捩预测方法是飞行器层流减阻设计的关键。本文针对未来飞行器对层流减阻设计的强烈需求,发展了三种工程实用的转捩预测方法,分别为基于线性稳定性理论的双eN方法、基于流场当地变量的γ-Reθ转捩模型和一种基于动模态分解的DMD/eN转捩预测新方法。通过DLR-F4翼身组合体、镰刀形机翼及NLF0416自然层流翼型转捩预测算例的计算值与实验值对比,验证了所发展的转捩预测方法的正确性。以双eN方法为例,将转捩预测方法与优化方法结合,开展了针对中短程民机的跨声速层流机翼优化设计研究。结果表明,优化机翼相对于基准机翼减阻效果明显,证明了本文发展的转捩预测方法有较强的工程应用价值。

     

    Abstract: Efficient and reliable transition prediction methods are of great significance for the development of drag reduction technology through large extension of laminar flow over aircraft. To meet the strong need of engineering design of future laminar aircraft, this article focuses on the development and investigation of three types of transition prediction methods:1) a dual eN method based on linear stability analysis; 2) a γ-Reθ model based on localized flow variables; 3) a novel method combining dynamic model decomposition (DMD) and eN method. These methods are validated by the transition predictions for flows over the DLR-F4 wing-body configuration, the sickle-shaped wing, and the natural-laminar-flow airfoil NLF0416, etc. The results show that the predicted transition points or lines are in good agreement with the experimental data. The dual eN-method, served as an example of the transition prediction methods, is further demonstrated for aerodynamic design of a natural-laminar-flow wing for short-and medium-range transport aircraft. Remarkable drag reduction has been achieved, which shows that the developed transition prediction methods offer great potential for engineering applications.

     

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