自由圆射流对声激励的非线性响应分析  

An analysis of nonlinear response of free circular jets to acoustic excitation

作　　者：郭鹏 赵马杰 朱旻明[1] 叶桃红[1] GUO Peng;ZHAO Majie;ZHU Minming;YE Taohong(Department of Thermal Science and Energy Engineering,University of Science and Technology of China,Hefei 230027,China)

机构地区：[1]中国科学技术大学热科学和能源工程系,安徽合肥230027

出　　处：《中国科学技术大学学报》2019年第6期465-475,516,共12页JUSTC

基　　金：国家自然科学基金(51576182,91441117)资助.

摘　　要：声激励是控制流动和燃烧的有效手段.为研究声激励对圆射流流场的控制作用,采用大涡模拟方法计算了不同频率的声激励下的圆射流流场(Re=2020),分析了流场对声激励的非线性响应过程.对涡量和Q函数的分析表明流场拟序结构的变化与激励频率有关.通过传递函数分析及脉动速度的分解,揭示出扰动波在流场中有三种传播模式,即对流传播模式、声波—对流混合传播模式和声波传播模式,与实验结果符合较好.通过分析速度功率谱(PSD)在空间的分布,反映出激励引起湍流能量在频率空间的重新分配.研究表明,射流响应对激励频率的选择特性不仅表现在流场结构的变化,还与扰动波的传播模式密切相关.当激励频率在射流优势频率附近时,扰动波以对流模式传播,流场结构及能量在频域的分布都发生明显变化.Acoustic excitation is an effective means of flow and combustion control.To investigate the modulation effects of acoustic excitation on the circular jet,large eddy simulation was adopted to calculate the circular jet(Re=2020)submitted to acoustic modulation with different frequencies.The nonlinear response of the flow field to acoustic excitation was studied.The analysis of vorticity field and Q criterion demonstrate that the response of the flow field structure is dependent on the excitation frequency.The analysis of transfer function and decomposition of fluctuating velocity reveal that the propagation of perturbation wave has three modes:convective mode,mixed acoustic-convective mode and acoustic mode,which agrees well with the experimental results.The spatial distributions of power spectrum density(PSD)of velocity display the redistribution of turbulent energy in the frequency space.It is shown that the response of jets to excitation reflects the flow structures and is closely related to the propagation mode of the perturbations.When the excitation frequency is near the preferred frequency of the jet,the perturbations propagate in a convective mode,while the flow structures and energy distribution in frequency space exhibit a significant change.

关 键 词：射流 声激励 传播模式 大涡模拟 

分 类 号：TK121[动力工程及工程热物理—工程热物理]