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细长旋成体亚声速超大攻角非定常流动特性研究

SUBSONIC UNSTEADY AERODYNAMIC CHARACTERISTICS ON SLENDER REVOLUTIONARY BODY AT EXTRA-WIDE ANGLE-OF-ATTACK

  • 摘要: 空空导弹作为现代空战的主要攻击手段, 要求比目标飞机更高的机动性和敏捷性. 新型空空导弹在面对新一代飞机时必须具备全方位攻击能力, 尤其对来自后方目标的威胁, 则需要更高转弯率和更大机动包络线的航向反转机动等先进高效机动方法. 为了保证高效机动的顺利完成, 要求导弹在超大攻角(α = 0° ~ 180°)范围内具有飞行和机动控制能力. 以往对超大攻角流动的观测和研究大多集中在α = 40° ~ 60°范围内, 最大角度不超过90°. 本文采用数值模拟(delayed detached eddy simulation, DDES)与风洞试验(油流显示试验)结合的方法, 研究了细长体亚声速下(Ma = 0.6)攻角α = 0° ~ 180°范围内的瞬时流动特性以及非定常特性. 研究表明, 数值模拟与油流显示试验获得的物面流线吻合较好, 在攻角α = 0° ~ 90°范围内, 细长体背风侧流动主要为圆柱段引起的集中涡主导, 体现为非对称、非定常和涡脱落等流动现象; 在攻角α = 90° ~ 180°范围内, 这时细长体底部朝前, 由此带来较大的回流区, 回流区内存在较多小尺度旋涡相互作用干扰, 随着流动逐渐沿轴向向后发展, 背风侧流动逐渐以非对称涡流动为主导. 非对称旋涡诱导的物面压力脉动频率St范围St = 0.19 ~ 0.33, 底部回流区诱导的物面压力脉动St范围为St = 1.55 ~ 1.64.

     

    Abstract: As the main means of attack in modern air combat, air-to-air missile requires higher maneuverability and agility than target aircraft. What’s more, in the face of the new generation of aircraft, the new air-to-air missile must possess all-round attack capability, especially to the threat from the rear target. Therefore, advanced and efficient maneuver methods such as higher turning rate and larger maneuver envelope are needed. In order to ensure the successful completion of efficient maneuvering, the new advanced air-to-air missile is required to have flight and maneuvering control capability within the range of extra-wide angle-of-attack (α = 0° ~ 180°). In the past, most of the observation and research on unsteady flow with extra-wide large angle-of-attack were concentrated in the range α = 40° ~ 60°, and the maximum angle-of-attack was less than 90°. In this paper, numerical simulation (delayed detached eddy simulation, DDES) and wind tunnel test in FD-12 (oil-flow visualization experiment) are used to study the transient flow characteristics and unsteady characteristics in Mach number 0.6 at the angle-of-attack of α = 0° ~ 180° of the slender revolutionary body. At the angle-of-attack of α = 0° ~ 90°, the flow on the leeward side of the slender revolutionary body is mainly dominated by concentrated vortices caused by cylindrical segments, which are characterized by asymmetric vortice, unsteady vortice and vortex shedding. At the angle-of-attack of α = 90° ~ 180°, the bottom of the slender revolutionary body is forward, which leads to a large separation area, and many small-scale eddy interaction in the separation area. As the flow gradually develops backward along the axial direction, the leeward flow is gradually dominated by asymmetric vortex flow. The frequency St number of surface fluctuating pressure induced by asymmetric vortices ranges from 0.19 to 0.33, and the frequency St number of surface fluctuating pressure induced by bottom separation region ranges from 1.55 to 1.64.

     

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