AC/NS-DBD等离子体激励分离剪切层的涡量输运特性  

Vorticity transport characteristics of separated shear layer under AC/NS-DBD plasma actuation

作　　者：赵光银 杨永东[1] 李婷婷 肖春华[1] 阎丽[1] ZHAO Guangyin;YANG Yongdong;LI Tingting;XIAO Chunhua;YAN Li(Low-speed Aerodynamics Institute of China Aerodynamics Research and Development Center,Mianyang 621000,China)

机构地区：[1]中国空气动力研究与发展中心低速空气动力研究所,四川绵阳621000

出　　处：《空气动力学学报》2023年第12期48-60,共13页Acta Aerodynamica Sinica

基　　金：国家自然科学基金(11802341)。

摘　　要：AC-DBD激励和NS-DBD激励是等离子体流动控制中的典型激励形式。研究发现二者均能在翼型分离剪切层处诱导形成展向涡,进而实现流动控制。为深入理解AC-DBD激励和NS-DBD激励在诱导展向涡形成上的区别,在Ma=0.1、Re=7.5×10^(5)条件下开展数值模拟,研究了两种激励对翼型大迎角(α=20°)分离的控制。将AC-DBD激励和NS-DBD激励分别以空间分布的动量源项和能量源项的形式耦合到非定常雷诺平均Navier-Stokes方程。引入二维涡量动力学方程,分析了两种激励诱导展向涡量的来源。在激励施加时,对于AC-DBD激励,涡量体积力项是边界涡量变化的主要来源;对于NS-DBD激励,涡量斜压项是边界涡量变化的主要来源。在两种激励施加结束后1 ms时,前缘上翼面附近逐渐形成展向涡结构;展向涡形成后,发现两种激励诱导当地涡量变化的主要因素均是对流项,区别最大的是斜压项,其次是斜黏项,原因是NS-DBD激励后的残留热引起了流体密度梯度和机械应力(黏性应力和压力)梯度的不平行。通过分析AC-DBD激励诱导涡量的变化和发展,提出了提升前缘AC-DBD激励控制流动分离效果的反向激励方法。AC-DBD actuation and NS-DBD actuation are two typical actuation forms in plasma flow control,both of which can induce spanwise vortices in the separated shear layer to control the flow.In order to understand the difference between AC-DBD actuation and NS-DBD actuation in the formation of induced spanwise vortices,flow separation control by the two actuations on the airfoil at a high angle of attack(α=20°)is investigated numerically at Ma=0.1,Re=7.5×10^(5).The AC-DBD actuation and the NS-DBD actuation are coupled to the unsteady Reynolds averaged Navier-Stokes equations in the forms of spatially distributed momentum source term and energy source term,respectively.The two-dimensional vorticity evolution equation is used to analyze the source of the induced spanwise vorticity.For AC-DBD actuation,the body force term is the main source of the boundary vorticity variation;while for NS-DBD actuation,the baroclinic term is the main source of the boundary vorticity variation.At 1 ms after the actuation,spanwise vortex structures are gradually formed on the upper wing surface around the leading edge.Then,it is found that the main cause of the local vorticity variation for the two kinds of actuations comes from the convective term.For the vorticity transport under the two actuations,the largest difference lies in the baroclinic term,followed by the cross product of density gradient and viscous force gradient,due to the non-parallel of the fluid density gradient and the mechanical stress(viscous stress and pressure)gradient caused by the residual heat after the NS-DBD actuation.By analyzing the variation and development of the vorticity induced by the AC-DBD actuation,a reverse actuation method is proposed to improve the flow control effect of the leading-edge AC-DBD actuation.

关 键 词：分离剪切层 等离子体激励 展向涡 涡量输运方程 介质阻挡放电 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程] O539[理学—等离子体物理]