报告摘要：
Methods of controlling flow separation on aircraft have been sought for decades. While conventional vane vortex generators are in frequent use, other means of control are still being sought to provide more efficient aircraft operation, manufacture and performance. Being a type of promising devices for such an application, synthetic-jet actuators have been the focus of intense research for many years. A synthetic jet is a massless jet synthesised from a train of vortex rings emitted from a circular orifice of a cavity which has an oscillating diaphragm attached to one of its walls. It is believed that the interaction between these vortex rings and a boundary layer produces streamwise vortical structures, which are capable of delaying flow separation by entraining faster moving fluid from the freestream to the near-wall region. Nevertheless, despite the proven capability of synthetic jet actuators in delaying flow separation in laboratory experiments, successful applications of these devices at practical settings still wait for a better understanding of the fluid mechanism of synthetic jets. In this seminar, the results from a combined experimental and numerical study of synthetic jets will be presented. The aims of this work are to investigate the detailed nature of vortical structures produced by the interaction of a single synthetic jet with a zero-pressure-gradient boundary layer and its near-wall effect, and to examine the flow control effect of a synthetic jet array operating at different actuation conditions on a separated boundary layer. Based these studies, the mechanism of flow separation delay using synthethic jets is proposed and the actuator operating conditions which yield the best flow control effect with the least energy consumption are also identified. The outcome from this research would be useful to the development of more effective synthetic-jet actuators for practical settings.
钟山简介：
清华大学取得工学学士、工学硕士学位，剑桥大学获得博士学位。
钟山博士一直从事流体流动的研究，专注于研究复杂流体现象的流动机理，擅长使用各种实验方法，尤其是PIV和流动可视化技术。钟山博士是美国航天宇航协会的终身高级成员，同时也是英国皇家航空协会的成员。
时间：2013年10月25日下午15:00-17:00
