Experimental assessment of spanwise-oscillating dielectric electroactive surfaces for turbulent drag reduction in an air channel flow
Experimental assessment of spanwise-oscillating dielectric electroactive surfaces for turbulent drag reduction in an air channel flow
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DOI：
10.1007/s00348-015-1983-x
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发表时间：
2015-05-01
影响因子：
2.4
通讯作者：
Tropea, Cameron
中科院分区：
文献类型：
--
作者：
Gatti, Davide;Guettler, Andreas;Tropea, Cameron
在目前的工作中，壁面振荡的湍流表面摩擦阻力的减少实现了在空气湍流管道流的展向振荡的活性表面的基础上的电介质电活性聚合物。致动器系统产生820 mm/s半振幅的展向壁速度振荡，其共振频率为65 Hz，同时消耗几个100 mW的有功功率。作动器实现了2.4%的最大整体减阻。最大净功率节省，预算的功率效益和成本的控制，是第一次测量与壁振荡。虽然是负的，但净节能比以前的研究估计的要高出一个数量级。两个新的直接数值模拟的湍流通道流表明，有限尺寸的致动器只能部分地解释较低的值的积分减阻通常在实验室实验中实现的数值模拟相比。
In the present work, wall oscillations for turbulent skin friction drag reduction are realized in an air turbulent duct flow by means of spanwise-oscillating active surfaces based on dielectric electroactive polymers. The actuator system produces spanwise wall velocity oscillations of 820 mm/s semi-amplitude at its resonance frequency of 65 Hz while consuming an active power of a few 100 mW. The actuators achieved a maximum integral drag reduction of 2.4 %. The maximum net power saving, budget of the power benefit and cost of the control, was measured for the first time with wall oscillations. Though negative, the net power saving is order of magnitudes higher than what has been estimated in previous studies. Two new direct numerical simulations of turbulent channel flow show that the finite size of the actuator only partially explains the lower values of integral drag reduction typically achieved in laboratory experiments compared to numerical simulations.