高超声速边界层转捩的几点认识  

Recent progresses on hypersonic boundary-layer transition

作　　者：陈坚强[1,2] 袁先旭[1,2] 涂国华[1] 陈久芬[3] 张毅锋[1] 徐国亮[1] 童福林[1] 万兵兵 CHEN JianQiang;YUAN XianXu;TU GuoHua;CHEN JiuFen;ZHANG YiFeng;XU GuoLiang;TONG FuLin;WAN BingBing(State Key Laboratory of Aerodynamics,China Aerodynamics Research and Development Center,Mianyang 621000,China;Computational Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China;Hypervelocity Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China)

机构地区：[1]中国空气动力研究与发展中心,空气动力学国家重点实验室,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,绵阳621000 [3]中国空气动力研究与发展中心,超高速空气动力研究所,绵阳621000

出　　处：《中国科学：物理学、力学、天文学》2019年第11期121-134,共14页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家重点研发计划(编号:2016YFA0401200);国家自然科学基金(编号:11772350,11872370)资助项目

摘　　要：边界层转捩问题是高超声速飞行器研制过程中必须关注的关键问题之一,世界各航空航天大国都大力支持相关研究,且近几年的资助呈现增长趋势.本文结合风洞实验、数值模拟和理论分析,对该领域目前存在的一些热点问题开展了相关研究,并提出了自己的观点.(1)在Φ1 m高超声速风洞中得到了单位雷诺数、攻角和头部钝度对钝锥边界层转捩的影响规律.(2)头部钝度对高超声速边界层转捩的影响存在趋势反转现象,但国际学术界迄今尚未找到合理解释.本文提出应考虑前缘激波对自由流扰动的影响,同时应从钝前缘感受性和熵层效应两个角度研究这种反转现象.本文从这两个角度出发,通过直接数值模拟(DNS)和稳定性分析获得了一些初步结果.(3)在转捩后期,第二模态扰动波增长到一定阶段后会出现安静区,紧接着出现低频模态,本文通过DNS和模态分解等方法揭示了第二模态和低频模态之间的关系.(4)最后介绍一种新的饱和横流涡二次失稳模态,它的增长率与Z模态相当,但是由法向剪切引起,被命名为Y′模态.Boundary-layer transition(BLT) is one of the key problems in developing hypersonic aircrafts. Major aerospace countries all over the world have been heavily supporting relevant researches, and the project funding keeps increasing in recent years. In this paper, wind tunnel experiments, numerical simulations and theoretical analysis are combined to study some hot issues in this area, which include effects of unit Reynolds number, angle of attack and nose bluntness,nonlinear interactions during breakdown, secondary instability of crossflow vortices, etc. Some of our views on understanding hypersonic BLT are summarized. The wind tunnel tests are conducted in the Φ1 m hypersonic wind tunnel of China Aerodynamics Research and Development Center, and the relation between transition location and different unit Reynolds numbers, angles of attack and nose bluntness is obtained. It is well known that hypersonic BLT undergoes an important phenomenon called "nose-bluntness inversal", but a worldwide accepted reasonable explanation for this phenomenon is still missing. To investigate the "nose-bluntness reversal", we suggest to consider the influence of front shock waves because free-stream disturbances are changed by shock waves. Meanwhile, we should also consider the following two aspects: blunt-nose receptivity and entropy-layer effect. Some premiliary but encouraging results are presented on these two aspects via direct numerical simulations(DNS) and stablity analysis. During the late stage of transition, a "quiet zone" may appear when the second mode waves reach large amplitude, and this is followed by lowfrequency modes. DNS and the dynamic mode decomposition are applied to study this problem. The results indicate that the relation between the second modes and the low-frequency modes is possibly mode transformation. In the end of this paper, a newly discovered secondary unstable mode of saturated crossflow vortices is introduced. This mode has the same level of growth rate as Z mode, but is related to the wall-normal s

关 键 词：高超声速 边界层转捩 感受性 二次失稳 钝锥 

分 类 号：V21[航空宇航科学与技术—航空宇航推进理论与工程]