激流丝扰动下回转体边界层流动转捩的模态特征  

Mode characteristics of transition flow in the boundary layerof the revolved body under wire spoiler disturbances

作　　者：赵祎佳 肖加兵 刘建华 李孝检 赵明[2] ZHAO Yijia;XIAO Jiabing;LIU Jianhua;LI Xiaojian;ZHAO Ming(School of Mechanical Engineering,Tianjin University of Commerce,Tianjin 300134,China;School of Mechanical Engineering,Tianjin University,Tianjin 300354,China;Taihu Laboratory of Deepsea Technological Science,China Ship Scientific Research Center,Wuxi 214082,China)

机构地区：[1]天津商业大学机械工程学院,天津300134 [2]天津大学机械工程学院,天津300354 [3]中国船舶科学研究中心深海技术科学太湖实验室,无锡214082

出　　处：《实验流体力学》2024年第2期59-67,共9页Journal of Experiments in Fluid Mechanics

基　　金：国家自然科学基金项目(91952301,12102298);天津市教委科研计划项目(2023KJ205)。

摘　　要：水下航行体首部边界层转捩会产生较强的噪声,严重影响其通信及探测性能。为探明诱发水动力噪声的主要流动结构,本文以SUBOFF缩比模型为研究对象,采用高速水洞实验及大涡模拟方法,获得激流丝扰动下的水下回转体边界层流场。研究发现:边界层内流动在激流丝下游形成分离泡,在分离泡中后部发生转捩,诱发了大量多尺度非定常涡系。采用本征正交分解方法研究了边界层转捩区流向、法向速度脉动及压力脉动的模态特征,发现流向速度脉动的主导模态是分离泡及其沿流向的破碎和下游流向涡,其中分离泡区域流向速度脉动为低于3000 Hz的复合频率,下游流向涡为低于200 Hz的低频结构。法向速度脉动与压力脉动模态特征相似,都呈现出高频、宽频脉动特征,在分离泡附近强度最大。由此推测,分离泡及其破碎是边界层转捩的主要诱因,其诱发的法向速度脉动是产生高/宽频噪声的主要原因,流向速度脉动仅与低频噪声有关。The boundary layer transition of underwater vehicles produces strong noise,whichseriously affects the communication and detection performance.In order to explore the main flowstructures that induce the flow noise,a SUBOFF model is used as the research object,and theexperiment and the large eddy simulation method are used to obtain the boundary layer flow fieldof the underwater revolved body under wire spoiler disturbances.The flow in the boundary layerfirst forms a separation bubble downstream of the wire spoiler,and a transition occurs in theposterior part of the separation bubble,which induces a large number of multi-scale unsteadyvortices.Furthermore,based on the proper orthogonal decomposition method,the modecharacteristics of the streamwise and normal velocity pulsation as well as the pressure pulsationin the boundary layer transition zone are studied.It is found that the dominant mode of the streamwise velocity pulsation is the separation bubble and its breakdown along the streamwisedirection as well as streamwise vortex downstream.The streamwise direction pulsation in theseparated bubble area has a composite frequency of<3000 Hz,and in the downstream vortexregion has a low-frequency structure of<200 Hz.The mode characteristics of the normal velocitypulsation and pressure pulsation are similar.They are both high-frequency,broad-frequencymodal structures with the greatest intensity near the separation bubble.It is inferred that theseparation bubble and its breakdown are the main inducements of boundary layer transition,theinduced normal velocity pulsation is the main source of high/broadband noise,and thestreamwise velocity pulsation is only related to low frequency noise.

关 键 词：水下回转体 激流丝 大涡模拟 本征正交分解 模态特征 

分 类 号：TV131.2[水利工程—水力学及河流动力学]