Direct Numerical Simulation on Mach Number and Wall Temperature Effects in the Turbulent Flows of Flat-Plate Boundary Layer  

作　　者：Xian Liang Xinliang Li 

机构地区：[1]School of Mathematics and Information Science,Beifang University for Nationalities,Yinchuan 750021,China [2]LHD,Institute of Mechanics,Chinese Academy of Sciences,No.15 Beisihuanxi Road,Beijing 100190,China

出　　处：《Communications in Computational Physics》2015年第1期189-212,共24页计算物理通讯（英文）

基　　金：This work is supported by the NSFC Projects(No.11072248);the 973 Program(No.2009CB724100);the 863 Program(No.2012AA01A304);the CAS Information Project(INFO-115-B01).The authors thank the Supercomputing Center of the Chinese Academy of Sciences(SCCAS),the Shanghai Supercomputer Center(SSC)and the National Supercomputing Center in Tianjin(NSCC-TJ)for providing the computing time.

摘　　要：In this paper,direct numerical simulation(DNS)is presented for spatially evolving turbulent boundary layer over an isothermal flat-plate at Ma∞=2.25,5,6,8.When Ma∞=8,two cases with the ratio of wall-to-reference temperature T_(w)/T_(∞)=1.9 and 10.03 are considered respectively.The wall temperature approaches recovery temperatures for other cases.The characteristics of compressible turbulent boundary layer(CTBL)affected by freestream Mach number and wall temperature are investigated.It focuses on assessing compressibility effects and the validity of Morkovin’s hypothesis through computing and analyzing the mean velocity profile,turbulent intensity,the strong Reynolds analogy(SRA)and possibility density function of dilatation term.The results show that,when the wall temperature approaches recovery temperature,the effects of Mach number on compressibility is insignificant.As a result,the compressibility effect is very weak and the Morkovin’s hypothesis is still valid for Mach number even up to 8.However,when Mach number equal to 8,the wall temperature effect on the compressibility is sensitive.In this case,when T_(w)/T_(∞)=1.9,the Morkovin’s hypothesis is not fully valid.The validity of classical SRA depends on wall temperature directly.A new modified SRA is proposed to eliminate such negative factor in near wall region.Finally the effects of Mach number and wall temperature on streaks are also studied.

关 键 词：HYPERSONIC directly numerical simulation compressibility effects turbulent boundary layer strong Reynolds analogy 

分 类 号：O35[理学—流体力学]