Suppression of vortex shedding from a pantograph head using vortex generator-type plasma actuators

Abstract

A vortex generator (VG) is one of the most successful devices used for suppression of flow separation. A conventional VG is a passive control device, so that it may suffer from an inherent drag penalty. As an alternative, we use a dielectric-barrier-discharge plasma actuator (PA) as a VG. Since few studies have been made on such a vortex generator-type plasma actuator (VG-PA), many questions still remain open, e.g., the effectiveness and the performance of the VG-PA for suppression of vortex shedding from a bluff body. In the present study, we experimentally evaluate the performance of the VG-PA by applying it to a pantograph head model of high-speed trains. The Reynolds number based on the freestream velocity and the width of the pantograph head model is 7200. The spanwise velocity induced by the VG-PA is about 33% of the freestream velocity. The flow field is measured by using particle image velocimetry. The present results show that the vortex shedding from a pantograph head model can significantly be suppressed by the VG-PA, which amounts to about 60% reduction in the transverse velocity fluctuations. It is also shown that a burst discharge control significantly improves the control effect in the single-side configuration, in which the vortex shedding is not much suppressed in the continuous mode.

Keywords

• flow separation control
• plasma actuator
• vortex generator
• pantograph head
• burst signal input