Advances in the study of methods and mechanism\\ of
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摘要:首先从涡脱落生成理论出发对钝体尾流控制方法进行了分类,并简单介绍了国内尾流控制研究情况.之后介绍了我们用窄条或小方柱取代小圆柱后,对Strykowsky和Sreenivasan控制方法的改进及其在高雷诺数下对圆柱和方柱尾流涡脱落的有效抑制情况,并探讨了控制件钝度对抑制效果的影响.第3部分用实验数据对各个涡脱落生成模型做了分析与检验,指出控制件方法的机理与改变钝体分离位置、减小钝体背压吸力、改变流动的展向相关性、防止钝体两侧剪切层相互作用等无关,而与钝体近尾流速度剖面的局部修正及其稳定性的改变有关.最后简单介绍了控制件方法今后研究工作展望及其工程应用前景.Abstract:In the first section,we classify the control methods of vortex shedding in bluff bodywakes according to the control ideas that originate from thetheoretical models of vortex generation, and then brieflyintroduce the recent works of the control in china. In the secondsection, we present our work on a modified Strykowski \&Sreenivasan's method, in which the circular control element isreplaced by an element of strip or square cross-section. Theresult shows an improvement on suppression of vortex shedding froma circular cylinder and from a square cylinder at high Reynoldsnumber flow. The influence of the degree of control element'sbluffness on the suppression is investigated. In the thirdsection, the theoretical models of vortex generation are analyzedand examined by using experimental data. We conclude that themechanism of the element control is not related to the change ofseparation position or to the reduction of base suction, or to thechange of span-wise correlation of the flow, or to the preventionof interactions between the separated shear layers, but is relatedto the local modifications of the velocity profiles downstream thebluff body and the change in their instability nature. In thefinal section, we discuss the future study of the control elementmethod and the prospects for engineering applications.
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