Plasma virtual roughness elements for cross-flow instability control
Plasma virtual roughness elements for cross-flow instability control
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DOI：
10.1007/s00348-018-2609-x
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发表时间：
2018-10
影响因子：
2.4
通讯作者：
K. Choi;Jung‐Hoon Kim
中科院分区：
文献类型：
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作者：
K. Choi;Jung‐Hoon Kim
最近的实验和数值模拟表明，离散粗糙元可以用来控制后掠机翼的横流不稳定性。在这里，这种被动技术的应用需要一排薄的圆柱形元件的几微米高的直接下游的前缘，以激发次临界模式的横流不稳定性。通过适当选择粗糙元的展向间距，可以抑制大多数不稳定模态的增长，从而延迟转捩。然而，这种控制横流不稳定性的被动技术对离散粗糙度的大小（直径和高度）、形状和位置非常敏感。为了模仿离散的粗糙度元素，并能够动态地调整粗糙度参数，虚拟粗糙度元素的基础上介质阻挡放电等离子体致动器已被开发和测试。在本文中，我们通过描述虚拟粗糙元与进入的层流边界层相互作用产生涡流的机制，展示了用于横流不稳定性控制的几种不同原型虚拟粗糙元的等离子体诱导流场。图形摘要
AbstractRecent experiments and numerical simulations demonstrated that discrete roughness elements can be used to control cross-flow instability over a swept wing. Here, the application of this passive technique requires a row of thin cylindrical elements of a few microns high immediately downstream of the leading edge to excite the subcritical modes of cross-flow instability. By properly choosing the spanwise spacing of these roughness elements, one can suppress the growth of most unstable modes, thereby delay transition. However, this passive technique of controlling cross-flow instability is very sensitive to the size (diameter and height), shape and location of discrete roughness. To mimic the discrete roughness elements and to be able to adjust the roughness parameters dynamically, virtual roughness elements based on dielectric-barrier-discharge plasma actuators have been developed and tested. In this paper, we show the plasma-induced flow field of several different prototype virtual roughness elements for cross-flow instability control, by describing the mechanisms of vortex generation from the virtual roughness elements through an interaction with the incoming laminar boundary layer.Graphical abstract