三角翼的垂直涡阵风遭遇

中文摘要 AI 辅助

本研究采用直接数值模拟方法，分析了在攻角10度、雷诺数1000条件下，一个垂直涡与后掠角60度的无尾NACA 0012三角翼的遭遇。鉴于在城市峡谷、山区、野火或车辆集群等复杂环境中飞行的需求，我们聚焦于垂直涡阵风对三角翼的影响，以补充先前主要研究展向和流向涡遭遇的工作。垂直方向可在所有六个自由度上施加强烈的瞬态载荷，我们特别关注将这些载荷与流动响应联系起来。通过改变阵风的横向位置、尺寸和强度，我们发现了一个表征垂直涡阵风遭遇的基本过程。阵风始终在翼面留下一个低压核心。演化的核心产生逆压梯度，扭曲了基准的表面摩擦模式，并诱发分离，抬升边界层。这些抬升的边界层被阵风的应变拉长并扭曲成瓣状涡结构，力元分析表明这些结构对升力有至关重要的贡献。当阵风的横向位置从翼根变化到翼尖时，低压核心和诱发的流动分离越来越集中在最靠近阵风的前缘附近，改变了瓣的演化，并导致力和力矩响应随阵风位置的变化呈现复杂依赖性，而相比之下，它们随阵风尺寸和强度的变化则基本呈单调关系。

英文摘要

The present study analyzes encounters of a vertical vortex with a tailless NACA 0012 delta wing with a sweep angle of 60 degrees at an angle of attack of 10 degrees and Reynolds number 1000 using direct numerical simulations. Motivated by the need to fly in complex settings such as urban canyons, mountainous areas, wildfires, or vehicle swarms, we focus on the influence of a vertical vortex gust on the delta wing, complementing previous efforts that predominantly studied spanwise and streamwise vortex encounters. The vertical orientation can impose strong transient loads on all six degrees of freedom, and particular attention is devoted to connecting these loads to the flow response. By varying the gust's lateral position, size, and strength, we find a fundamental process that characterizes vertical vortex gust encounters. The gust consistently imprints a low-pressure core on the wing surface. The evolving core creates an adverse pressure gradient that distorts the baseline skin-friction pattern and induces separation that lifts the boundary layers. These lifted boundary layers are elongated and twisted by the gust's strain into lobed vortical structures, which are shown by force element analysis to make a critical contribution to the lift. As the gust's lateral position is varied from root to tip, the low-pressure core and the induced flow separation are increasingly localized around the leading edge closest to the gust, modifying the lobe evolution and leading to complex dependence of the force and moment response on gust position compared to the largely monotonic dependence on gust size and strength.

发表机构

• University of California, Los Angeles（加州大学洛杉矶分校）

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