A Study on Promotion of the Near-Wall Turbulence Mixing by Phase Control of the Pulsed Vortex Generator Jet Row.

湍流边界层中的涡发生器射流具有主动控制边界层失速的重要潜力，因此本文对其进行了研究。本课题研究的是脉冲涡发生器射流通过单孔在边界层中产生周期性纵向涡。采用高响应流量传感器测量了相平均流速和壁面剪应力。在某些脉冲注射条件下，在注射孔下游和注射结束时靠近壁面的区域观察到较高的速度。相平均壁剪应力在注入结束时达到峰值。得到了最佳注射条件。此外，双射流的重要流动参数是它们的排列和喷射相位差。在共相共流向下排列时，相平均壁面剪应力在喷射结束时的峰值高于单射流。因此，通过脉冲注入在壁面附近形成的低动量流体的扫掠效应对抑制边界层分离是有效的。

A vortex generator jet in a turbulent boundary layr has been investigated, since it has a significant potential for the active control of boundary layr stall. The present project concerns the pulsed vortex generator jet through a single hole which generates periodic longitudinal vortices in the boundary layr. Phase averaged streamwise velocity and wall shear stress were measured by a flow sensor with a high response. Under some pulsed ingection conditions, higher velocity is observed in the region downstream of the injection hole and close to wall at the end of injection. Phase averaged wall shear stress has a peak at the end of injection. The optimum injection condition is also obtained.Furthermore, the important flow parameters of double jets are their arrangement and phase difference of injection. In common flow down arrangement with the common phase, phase averaged wall shear stress has a higher peak at the end of injection than that of single jet. As a result, such a sweep-effect of low momentum fluid near the wall by a pulsed injection is effective in the suppression of the boundary layr seperation.