可压缩壁湍流热力学量统计特性分析  

Statistical properties of thermodynamic fluctuations in compressible wallbounded turbulence

作　　者：傅亚陆 袁先旭[1] 刘朋欣 余明 FU Yalu;YUAN Xianxu;LIU Pengxin;YU Ming(State Key Laboratory of Aerodynamics,Mianyang 621000,China)

机构地区：[1]空气动力学国家重点实验室,绵阳621000

出　　处：《航空学报》2023年第9期156-169,共14页Acta Aeronautica et Astronautica Sinica

基　　金：国家重点研发计划(2019YFA0405200);空气动力学国家重点实验室创新基金(SKLA-JBKYC190109);国家数值风洞工程;国家自然科学基金(92052301)。

摘　　要：可压缩壁湍流中的速度脉动统计特性已经得到了较为广泛的研究,而热力学量脉动及其互相关的研究依然较少。为了探明压缩性对热力学量脉动的影响机制,对直接数值模拟数据库进行分析,对可压缩槽道湍流中温度、熵、密度和压力等热力学量的相干结构和统计特性随法向高度、马赫数和壁温的变化规律开展系统研究。统计结果表明,在壁面附近,压缩性效应对相干结构形态和统计特性的影响十分明显,主要表现为与强压缩事件相关的正密度脉动和压力脉动更强,使得其近壁处的偏斜度和平坦度更高,具有更强的不对称性和间歇性。而在远离壁面的外区,温度、熵和密度脉动的相干结构和统计特性随马赫数和壁温变化趋势类似,具有较强的相关性。速度脉动对温度和熵脉动的输运作用类似,表明可采用与温度脉动模型化相同的方法对熵脉动进行模型化。The statistical properties of velocity fluctuations have been widely investigated in compressible wallbounded turbulence.However,fluctuations of thermodynamic variables and their correlations require further understanding.This study exploits the direct numerical simulation databases to systematically investigate the effects of Mach numbers and wall temperatures on coherent structures and statistical properties(e.g.,root-mean-square,skewness/flatness factor,correlation)of thermodynamic variables(e.g.,temperature,entropy,density and pressure).It is found that the compressibility effects have significant influence on coherent structures and statistical properties in the near-wall region,manifested as stronger positive density/pressure fluctuations associated with strong compressive events,resulting in higher skewness and flatness that indicate stronger asymmetry and intermittency.Nevertheless,in the outer region,coherent structures and statistical properties of temperature/entropy/density fluctuations with different Mach numbers and wall temperatures show a similar trend with a strong correlation.In addition,velocity fluctuations have similar effects on the transport of temperature/entropy fluctuations,indicating that entropy fluctuations can be modeled in the same way as temperature fluctuations.

关 键 词：可压缩壁湍流 直接数值模拟 热力学量 相干结构 统计特性 湍流输运 

分 类 号：V411.3[航空宇航科学与技术—航空宇航推进理论与工程] O357.5[理学—流体力学]