Fundamental Study on Flow Characteristics of Synthetic Jets for Development of Blown Flap

射流已被应用于各个领域以控制流动分离。在过去的十年里，几项研究对合成喷气式飞机进行了研究。然而，仍有许多需要澄清，包括合成喷气式飞机的结构和科安达效应的细节。本文通过实验和数值模拟，阐明了自由合成射流和刚性边界附近合成射流的一些基本流动特性。结果表明，自由合成射流的速度分布依赖于K=Re/S^2(雷诺数与斯托克斯数的平方之比)，并可由中心线上的最大速度和射流半宽来确定。应用烟丝法进行了流动显示。此外，还证实了合成射流在刚性边界附近的流动特性和合成射流的再附着长度不仅取决于H_1/b_0(归一化台阶高度)，而且还取决于K。

The jet flows have been applied to various fields to control the flow separation. Over the last decade, several studies have investigated synthetic jets. However, there are still many clarifications needed, including details of the structure and Coanda effect of synthetic jets. The present study clarifies some fundamental flow characteristics of free synthetic jets and synthetic jets near a rigid boundary by conducting an experiment and numerical simulations. As the main results, it is found that the velocity distribution of free synthetic jets depends on K=Re/S^2(the ratio of the Reynolds number to the square of the Stokes number) and can be identified by the maximum velocity at the centerline and the jet half-width. Flow visualization is carried out applying the smoke wire method. In addition, it is confirmed that the flow characteristics of the synthetic jet near a rigid boundary and re-attachment length of the synthetic jet are determined not only by H_1/b_0(normalized step heights) but also K.