高亚声速射流的流声分离及束缚波特性分析  

HYDRODYNAMIC AND ACOUSTIC MODE DECOMPOSITION OF HIGH SUBSONIC TURBULENT JET AND ANALYSIS OF TRAPPED WAVE

作　　者：韩帅斌 王益民 武从海 罗勇 李虎 Han Shuaibin;Wang Yimin;Wu Conghai;Luo Yong;Li Hu(State Key Laboratory of Aerodynamics,Mianyang 621000,Sichuan,China;Computational Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,Sichuan,China)

机构地区：[1]空天飞行空气动力科学与技术全国重点实验室,四川绵阳621000 [2]中国空气动力研究与发展中心计算空气动力研究所,四川绵阳621000

出　　处：《力学学报》2024年第11期3142-3151,共10页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金资助项目(12202474,12102450,12172374和12372257).

摘　　要：高亚声速射流噪声是民航客机推进系统噪声的重要来源,其噪声组分包含了宽频湍流混合噪声和近来发现的近场离散频率束缚波.束缚波受到近场动力学脉动干扰,导致难以清晰识别其空间结构和传播特性.准确分离射流近场中的束缚波是揭示其物理特性的关键.文章发展了模态分解与物理属性耦合的HD-SPOD流声分离方法,可识别并分离脉动速度场的动力学模态和可压缩模态,其中可压缩模态可用于表征声模态并反映声模态的主要特征,为揭示流动近场流声特性提供了分析工具.应用该方法分析了射流马赫数为0.9的高亚声速射流的脉动速度场,获得了对应于束缚波频率的主导SPOD模态的动力学模态和声模态,并研究两种模态的空间结构特征和传播特性.研究发现:亚声速射流势核内不仅存在声模态束缚波,也存在动力学模态“束缚波”,其中声模态束缚波存在多阶径向结构,动力学模态“束缚波”沿径向则只存在单阶结构;声模态束缚波主要存在于势核前端,在势核内向上游传播;动力学模态“束缚波”则分布于整个势核内并向下游输运.The high subsonic turbulent jet noise is the main component of the aircraft propulsion system noise.The jet noise contains both the far field broadband turbulent mixing noise and the recently found near field discrete trapped wave.The trapped wave is buried in the strong hydrodynamic perturbation in the near field,which poses difficulty in revealing the spatial structure and propagation property of the trapped wave.Accurately decomposing the trapped wave in the near field of the jet is the key to reveal the physical property of trapped wave.To better understand trapped wave,the mode decomposition and physical property based HD-SPOD method for hydrodynamic and acoustic mode decomposition is developed.The method is able to separate the hydrodynamic and compressible component of the perturbation velocity field,with the latter being able to characterize the acoustic mode and reveal the main features of acoustic mode.The method provides tool for analyzing flow and acoustic features of the near flow field.The HD-SPOD method is applied to a jet Mach number 0.9 high subsonic turbulent jet.The hydrodynamic and acoustic modes of the leading SPOD modes whose frequencies corresponding to the trapped wave are decomposed.The spatial structure and propagation properties of the hydrodynamic and acoustic modes are analyzed.It is found that in the subsonic turbulent jet potential core,both the acoustic trapped wave and hydrodynamic"trapped wave"exist.The acoustic trapped wave shows multi-radial order structures,while the hydrodynamic"trapped wave"only has single order radial structure.The acoustic trapped wave exists in the front part of potential core and propagates upstream,while the hydrodynamic"trapped wave"exists through the potential core and transports downstream.

关 键 词：亚声速射流 流声分离 束缚波 

分 类 号：O354.1[理学—流体力学] O358[理学—力学]