等离子体激励器诱导射流的湍流特性研究  

INVESTIGATION ON THE TURBULENT CHARACTERISTICS OF THE JET INDUCED BY A PLASMA ACTUATOR

作　　者：张鑫[1] 黄勇[2] 阳鹏宇[2] 唐坤[2] 李华星[1] Zhang Xin;Huang Yong;Yang Pengyu;Tang Kun;Li Huaxing(School of Aeronautics,Northwestern P olytechnical University,Xi ＇an 710072,China;China Aerodynamics Research and Development Center,Mianyang 621000,Sichuan,China)

机构地区：[1]西北工业大学航空学院,西安710072 [2]中国空气动力研究与发展中心,四川绵阳621000

出　　处：《力学学报》2018年第4期776-786,共11页Chinese Journal of Theoretical and Applied Mechanics

基　　金：装备预先研究项目资助(51313010204)

摘　　要：为了进一步掌握等离子体流动控制机理,完善等离子体激励器数学模型,提升等离子体激励器扰动能力,采用粒子图像测速技术,在静止空气下开展了介质阻挡放电等离子体激励器诱导射流特性研究.实验时,将非对称布局激励器布置在平板模型上,随后将带有激励器的模型放置在有机玻璃箱内,从而避免环境气流对测试结果的影响.基于激励器诱导流场,分析了激励电压对诱导射流特性的影响,揭示了较高电压下诱导射流近壁区的拟序结构,获得了卷起涡、二次涡等拟序结构的演化发展过程,计算了卷起涡脱落频率,阐述了卷起涡与启动涡的区别,初步探索了卷起涡的耗散机制.结果表明:(1)层流射流不能完全概括等离子体诱导射流特性,激励电压是影响射流特性的重要参数.当电压较低时,诱导射流为层流射流;当电压较高时,诱导射流的雷诺数提高,射流剪切层不稳定,层流射流逐渐发展为湍流射流.(2)等离子体诱导湍流射流包含着卷起涡、二次涡等拟序结构;在固定电压下,这些涡结构存在恒定的卷起频率.(3)当激励电压较高时,流动不稳定使得卷起涡发生了拉伸、变形,引起了流场湍动能增大,从而加速了卷起涡的耗散.研究结果为全面认识激励器射流特性,进一步挖掘激励器卷吸掺混能力,提升激励器控制能力积累基础.In order to understand the controlling mechanism of plasma actuator and develop the mathematical model of plasma actuator, the turbulent characteristics of the jet induced by a dielectric barrier discharge（DBD） plasma actuator in quiescent air was studied in a closed chamber using particle image velocimetry（PIV）. Here, an asymmetrical DBD plasma actuator was mounted on the plate model. First, measured time-averaged velocity field induced by the DBD plasma actuator indicated that voltage amplitude is an important parameter and could affect the flow characteristics of the induced jet. When the plasma actuator was driven at low voltage, the induced jet was a laminar wall jet. On the other hand, the Reynolds number of induced jet was improved and the shear layer was instability when the plasma actuator was actuated at high voltage. Then the induced jet became a turbulent wall jet. Secondly, the results of transient flow field structure suggested that the induced turbulent wall jet had some coherent structures, such as rolling up vortex and secondary vortex in the near-wall region. And these structures were linked to a dominant frequency of f_0= 109Hz. The rolling up vortices had the process of formation, movement, merging and breakdown. Thirdly, the rolling vortex was stretched and collapsed due to the instability of flow field when the plasma actuator was actuated at high voltage. Then turbulence kinetic energy of induced flow filed was increased and the breakdown of rolling vortex was accelerated. The turbulent characteristics of the induced jet could enhance the entrainment effect of plasma actuator between the outside airflow and boundary layer flow, which is very important for flow control applications.

关 键 词：湍流特性 射流 等离子体 介质阻挡放电 拟序结构 

分 类 号：V211[航空宇航科学与技术—航空宇航推进理论与工程]