| 双振子同异步振动主动控制湍流边界层减阻实验研究 |
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| 引用本文： | 白建侠,赵凯芳,程肖岐,姜楠.双振子同异步振动主动控制湍流边界层减阻实验研究[J].力学学报,2023,55(1):52-61. |
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| 作者姓名： | 白建侠 赵凯芳 程肖岐 姜楠 |
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| 作者单位： | *.天津仁爱学院数学教学部, 天津 301636 |
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| 基金项目： | 国家自然科学基金(12202309, 11972251, 11902218, 12172242, 12272265, 12202310), 中德合作研究小组基金项目(GZ1575)和中国博士后基金项目(2022M712357) |
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| 摘 要： | 本文以镶嵌在平板上沿展向对放的两个压电陶瓷振子为主动控制激励器,自主设计了零质量射流主动控制湍流边界层减阻实验方案.在风洞中开展了双压电振子同步和异步振动主动控制湍流边界层减阻的实验研究,实现了压电振子的周期扰动对湍流边界层多尺度相干结构的干扰和调制,施加控制后减小了壁面摩擦阻力,获得减阻效果.当异步控制100 V, 160 Hz工况时得到最大减阻率为18.54%.小波多尺度分析结果表明,施加控制工况中PZT振子的周期性扰动使得小尺度结构的湍流脉动强度增强,改变了近壁区大尺度和小尺度结构的含能分布,且异步控制工况比同步控制工况的减阻效果好.当双振子振动频率为160 Hz时,流向脉动速度的小波系数PDF曲线呈现出波动特征,尾部变宽显著,近壁湍流脉动更加有序和规则,湍流间歇性减弱.对小尺度脉动进行条件相位平均的结果表明,施加PZT周期扰动后使得大尺度结构破碎成为小尺度结构,小尺度脉动强度增强,实现减阻.随着流向位置离PZT振子越来越远,周期性扰动对相干结构的调制作用逐渐减弱.
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| 关 键 词： | 零质量射流 相干结构 压电振子 主动控制 减阻 |
| 收稿时间： | 2022-06-04 |
EXPERIMENTAL INVESTIGATION ON ACTIVE CONTROL TURBULENT BOUNDARY LAYER DRAY REDUCTION BY SYNCHRONOUS AND ASYNCHRONOUS VIBRATION OF DUAL VIBRATORS |
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| Affiliation: | *.Department of Mathematics, Tianjin Renai College, Tianjin 301636, China?.Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin 300354, China**.Tianjin Key Laboratory of Modern Engineering Mechanics, Tianjin 300354, China |
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| Abstract: | In order to achieve the drag reduction effect, the experimental scheme of zero-mass jet active control turbulent boundary layer is designed independently in the paper. Dual piezoelectric (PZT) oscillators as the active control actuators are symmetrically distributed embedded along the spanwise direction of the flat plate in turbulent boundary layer. The experimental investigation is carried out by synchronous (syn) and asynchronous (asyn) vibration active control mode to achieve drag reduction with the periodic vibration of dual PZT oscillators in a wind tunnel. It realizes the periodic interference and modulation to the multi-scale coherent structure in turbulent boundary layer. Furthermore, it reduces the skin friction and realizes drag reduction effect in all controlled cases.The consequence shows that the maximum drag reduction rate of 18.54% is obtained at 100 V, 160 Hz asynchronous vibration case.The multi-scale wavelet analysis of streamwise velocity shows that the energy of the small-scale coherent structure increases while the large-scale coherent structure decreases in all controlled conditions.Meanwhile, it adjusts the energy distribution of the large-scale and small-scale coherent structures in near-wall regions of turbulent boundary layer .The drag reduction effect of the asynchronous controlled case is better than the synchronous controlled case at the same voltage and frequency of vibration. When the vibration frequency of the PZT oscillators is 160 Hz, the PDF curves of the wavelet coefficient show the fluctuation characteristics and the tails of the PDF curve widen significantly. The pulsations of near-wall regions become more ordered and regular and the turbulence weakens intermittently after control in turbulent boundary layer.The results of the conditional phase averaging of small-scale coherent structure show that the periodic perturbations of the PZT oscillators enhance the turbulence intensity of the small-scale coherent structures. Furthermore, drag reduction effect is also achieved by breaking the large-scale coherent structure into the small-scale coherent structure. As the streamwise position is far away from the PZT oscillators, the modulation effect of the coherent structure in turbulent boundary layer gradually weakens. |
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