高频阵列电弧控制激波附面层干扰不稳定性机理研究

The unsteadiness of shock wave boundary layer interaction can cause extremely negative effect on internal and external flow for high speed vehicles. Novel high-frequency surface arc array becomes a research focus in supersonic shock wave boundary layer interaction flow control due to its high intensity, fast response, and simple structure. Therefore, an application is filed to start the mechanism investigation on using high-frequency surface arc array to control the unsteadiness of shock wave/boundary layer interaction. Based on high-frequency actuation array pattern, advanced testing and analytical methods such as nano-particle laser scattering, PIV, high-speed schlieren and dynamic pressure will be applied to reveal the thermal and vortex characteristic for high-frequency surface arc array. With comprehensive test and theoretical analysis on flow characteristic induced by actuation, the influence rule of actuation frequency, timing sequence and relevant parameters on control effect will be systematically discussed. Combined with flow visualization and surface dynamic pressure fluctuation, the operating process of high-frequency arc array actuation on interaction flow configuration will be analyzed and the control mechanism of shock wave boundary layer interaction unsteadiness will be revealed. The project findings are expected to establish theoretical model and general theory for shock wave boundary interaction controlled by high-frequency arc actuation array, which will provide fundamental research for further development of plasma flow control on shock wave boundary layer interaction.

激波附面层干扰不稳定性给高速飞行器的内外流动带来十分不利的影响。新型高频阵列表面电弧因其激励强度大、响应快、结构简单，成为超声速激波附面层干扰流动控制的研究热点。本项目申请开展高频阵列电弧控制激波/附面层干扰不稳定性机理研究。基于高频阵列式的激励模式，综合运用纳米粒子激光散射、PIV、高速纹影、动态压力等先进测试手段和分析方法，揭示高频阵列电弧等离子体激励的热效应和涡效应特性；通过激励诱导的流动特性综合测试与理论分析，系统研究激励频率、时序、参数对控制效果的影响规律；结合流动显示和壁面动态压力脉动，分析高频阵列电弧激励对干扰结构的作用过程，获得激波附面层干扰不稳定性流动控制机理；项目研究成果有望获得高频阵列电弧激励控制激波附面层干扰的理论模型和普适性理论，为激波附面层干扰等离子体流动控制发展提供基础支撑。

开展了阵列式高频电弧放电等离子体激励器控制超声速压缩拐角激波附面层干扰流动机理的实验研究和理论分析。综合运用高速纹影、粒子激光散射技术、动态压力、粒子图像测速技术等先进测试手段和分析方法，揭示阵列电弧等离子体激励的热效应和涡效应特性。结合流动显示和壁面动态压力脉动，分析高频阵列电弧激励对干扰结构的作用过程。发现控制机理主要包括热效应机理和涡效应机理。热效应机理就是通过改变激波前后的气流参数，使得激波减弱，能量达到一定程度后，消波现象明显。这也是通过等离子体在局部产生热气泡控制激波的主要机理。在高频激励的条件下激励器产生更多的微弱尾迹扰动结构，其空间尺度较小，这种尺度的尾迹结构释放的能量也不足以直接改变激波前后的气流参数，相应的控制机理也无法用热效应机理来解释。因此，进行了超声速风洞高频激励实验验证，深入揭示高频阵列式电弧激励对激波附面层的作用机制，其机理是激励产生热气泡在向下游传播的过程中，由于附面层的剪切效应，形成大量的尾迹涡结构，这些结构进一步促进附面层湍流化，增强其抵抗激波产生逆压梯度的能力，并在附面层内部形成一系列高频能量，进步改善了激波附面层干扰诱导的低频不稳定性，压缩拐角诱导的强分离激波在高频激励下转换成微弱的压缩波结构。通过超声速风洞实验验证；深入揭示了超声速流场高频阵列电弧等离子体动力学机制和流体动力学机制，探索建立了激波/附面层干扰高频等离子体流动控制理论模型。

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