Flow control effects of three types of nanosecond (NS) dielectric barrier discharge (DBD) plasma actuations in suppressing the flow separation of a compressor airfoil at low Reynolds number are investigated using large-Eddy simulation. It has been found that the NS DBD plasma actuation can effectively suppress the flow separation and two mechanisms behind the flow control effect have been uncovered. First, the NS DBD plasma actuation can induce distorted flow structure (DFS) within the flowfield, and the induced DFS of plasma actuations located upstream of the flow separation zone can bring the Kelvin–Helmholtz instability of the shear layer between mainstream flow and separated flow froward to the separation point. Then, a large-scale spanwise vortex, which promotes the mixing of the main flow and the separated flow, is induced within the flow separation zone, thus resulting in suppression of the flow separation. Second, the plasma actuation located at the blade leading edge can improve the momentum of the laminar boundary layer, owing to the propagations of compressive waves as well as DFS along the blade surface. The plasma actuation located within the separation zone fails to suppress the boundary-layer flow separation effectively because the induced DFS cannot influence the shear layer between mainstream flow and separated flow.

使用大涡模拟研究了三种类型的纳秒 (NS) 介质阻挡放电 (DBD) 等离子体驱动在抑制压缩机翼型在低雷诺数下的流动分离方面的流量控制效果。已经发现，NS DBD 等离子体驱动可以有效地抑制流动分离，并且揭示了流动控制效应背后的两种机制。首先，NS DBD 等离子体驱动会在流场内引起扭曲的流动结构（DFS），位于流动分离区上游的等离子体驱动的诱导 DFS 会导致主流流和分离流之间剪切层的 Kelvin-Helmholtz 不稳定性向前到分离点。然后，一个大规模的展向涡流，促进了主流和分离流的混合，在流动分离区内被诱导，从而导致流动分离的抑制。其次，由于压缩波和 DFS 沿叶片表面的传播，位于叶片前缘的等离子体驱动可以改善层流边界层的动量。位于分离区内的等离子体驱动未能有效抑制边界层流分离，因为诱导的 DFS 不能影响主流流和分离流之间的剪切层。