Control of Coherent Structure by Streamwise Vortices Induced by Plasma Actuators

涡轮机械内部的相干结构会导致涡轮机效率的降低和噪声的增加。在涡轮机械中，对相干结构进行控制是十分必要的。最近，提出了一种使用等离子体致动器的新方法。本研究的目的是利用等离子体激励器诱导的等离子体射流来控制平板叶片后的相干结构。不同的旋涡形成相对于等离子体射流的展向长度。下洗涡在平板叶片后产生中心流动。平板叶片后雷诺应力增加近25%，尾迹宽度减小。因此，涡轮机的涡轮机效率的增加是通过下洗涡流预期的。

The coherent structure in the turbo machines causes the reduction of the turbine efficiency and the increasing of the acoustic noise. It is necessary to control the coherent structure in the turbo machine. Recently, a new approach using the plasma actuators is proposed. The aim of this study is to control the coherent structure behind a flat plate blade using the plasma jet induced by the plasma actuators. The different vortices are formed with respect to the spanwise length of the plasma jet. The downwash vortices induce the centrally-directed flow behind the flat plate blade. Reynolds stress increases nearly 25% and the wake width decreases behind the flat plate blade. Therefore, the increase of the turbine efficiency of the turbo machines is anticipated by the downwash vortices.