Far-field drag extraction has the advantage over near-field integration of providing a phenomenological breakdown of drag. A decomposition into components linked to shock waves, viscous interactions and lift-induced vortices is straightforward for steady flows. A formulation by Van der Vooren and Destarac is used at Onera and by Onera's partners but is restricted to steady cases. A generalization to unsteady flows of Van der Vooren's formulation has been developed and tested on three unsteady cases in a previous work. The proposed method allowed the breakdown of drag into the three usual components only, the induced drag coefficient remaining however ill-defined. This unsteady formulation is here modified to better express the induced drag. A new drag component is identified as a propagation and acoustics contribution. The new formulation is then applied to complex cases: a 2D pitching NACA0012 profile in a viscous flow, the same pitching airfoil in an inviscid flow, a 3D elliptical wing in an inviscid flow and finally an OAT15A profile subject to buffet simulated by Zonal-DES computations.
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机译:远场阻力提取的优势在近场集成提供拖动的现象学崩溃。分解成与冲击波连接的组件,粘性相互作用和升力引起的涡流对于稳定流动是简单的。 Van der Vooren和Destarac的配方在Onera和Onera的合作伙伴中使用,但仅限于稳定的情况。在前一项工作中的三个不稳定案件中开发并测试了van der Vooren的制剂的不稳定流的概括。所提出的方法仅允许拖动到三个常规组件中,诱导拖动系数剩余仍然存在义。此不稳定的配方在此修改为更好地表达诱导的拖动。新的阻力组件被标识为传播和声学贡献。然后将新的配方应用于复杂的情况:在粘性流动中的2D俯仰NaCa0012轮廓,在缺陷流中的相同的俯仰翼型,缺陷流中的3D椭圆翼,最后通过Zonal-des模拟自助液的oat15a型材。计算。
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