Control of an axisymmetric turbulent wake by a pulsed jet
Control of an axisymmetric turbulent wake by a pulsed jet
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脉冲射流控制轴对称湍流尾流
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
A. Qubain
中科院分区：
文献类型：
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作者：
J. Morrison;A. Qubain
结果表明，轴对称尾迹主要受三种失稳机制的支配：在极低频率下回流气泡的轴对称“泵送”，在后驻点下游形成的螺旋涡结构引起的反对称涨落，以及分离剪切层的几种较高频率的轴对称失稳模式。减阻的环境要求更加强调钝体的底压恢复。钝体周围分离流的主动控制倾向于集中在二维体上[2，3]，证明了在接近von Karman脱落频率的频率下，通常通过控制吹气可以实现大的减阻。然而，在控制方面，尽管3D钝体在许多实际问题中出现了这种构型，但受到的关注却相当少。即使在那时，主动控制也倾向于关注分离的延迟[4]。在本工作中，我们证明了来自零净质量通量(ZNMF)装置的高频射流可以提高钝化后缘的基压。
It has been shown [1] that the axisymmetric wake is dominated by three types of instability mechanism: an axisymmetric “pumping” of the recirculation bubble at very low frequencies, antisymmetric fluctuations induced by a helical vortex structure that forms just downstream of the rear stagnation point and several higher-frequency, axisymmetric instability modes of the separated shear layer. The environmental requirement for drag reduction has placed a greater emphasis on base-pressure recovery of bluff bodies. The active control of separating flow around bluff bodies has tended to focus on 2D bodies [2, 3] demonstrating that large drag reductions are possible, usually by controlled blowing, at frequencies close to the von Karman shedding frequency. However, in terms of control, 3D bluff bodies have received considerably less attention even though this configuration appears in many practical problems. Even then, active control has tended to focus on the delay of separation [4]. In the present work, we show that the base pressure of a blunt trailing edge may be increased by a high-frequency jet from a zero-net-mass-flux (ZNMF) device.