Simulations of High -Speed Internal Flows using LES/RANS Models
Simulations of High -Speed Internal Flows using LES/RANS Models
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DOI：
10.2514/6.2009-1324
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发表时间：
2009-01
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影响因子：
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通讯作者：
J. Boles;J. Edwards;R. Baurle
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文献类型：
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作者：
J. Boles;J. Edwards;R. Baurle
本文给出了横向音速喷射乙烯进入马赫数为1.98的横流和马赫数为5的气流进入小规模进气/隔离器结构的计算研究。采用大涡模拟/雷诺平均N-S(LES/RANS)混合湍流模型，RANS部分采用两方程Menter-BSL闭合，LES部分采用Smagorinsky模型。依赖于模拟的湍流变量的随时间变化的混合函数被用来将闭合从RAN转移到LES。乱七八糟的结构通过使用“随机行走”回收/重新调整技术得以维持。用混合模型计算的乙烯注入结果表明，S与空军研究实验室收集到的拉曼散射数据非常吻合。利用LEE-S/RANS数据库检验了喷口下游强混合区施密特数恒定这一常用假设的正确性。与粒子成像测速仪(PIV)和德克萨斯大学获得的壁面压力数据进行了比较，预测了进入进气/隔离器的5马赫流量。文中给出了两种情况下的初步计算结果，其中一种情况下的激波串传播会导致进气不启动。在这里，计算方法似乎预测了比实验中显示的更多的流动分离，导致更强的激波列没有稳定在正确的位置。
Computational stud ies of transverse sonic injection of ethylene into a Mach 1.98 cro ss flow and Mach 5 flow of air into a subscale inlet / isolator configuration are presented . A hybrid large -eddy simulation / Reynolds -averaged Navier -Stokes (LES/RANS) turbulence model is used , with the two -equation Menter -BSL closure for the RANS part of the flow and a Smagorinsky -type model for the LES part of the flow . A time -dependent blending function, dependent on modeled turbulence variables, is used to shift the closure from RANS to LES. Turbulent st ructures are sustained through the use of a ‘random -walk’ recycling / rescaling technique . The ethylene injection results using the hybrid model show s very good agreement with the Raman scattering data collected at the Air Force Research Laboratory . The LE S/RANS database is used to examine the validity of the commonly -used assumption of a constant Schmidt number in the intense mixing zone downstream of the injection location . Predictions of Mach 5 flow into the inlet / isolator are compared with particle imaging velocimetry (PIV) and wall pressure data obtained at the University of Texas . Preliminary computational results are presented for two cases involving shock -train propagation within the isolator, one of which leads to inlet unstart. Here, the compu tational method appears to predict more flow separation than indicated in the experiment, leading to stronger shock trains that are not stabilized at the correct position.