锥体效应对超音速湍流边界层统计特性的影响

THE INFLUENCE OF THE TURBULENT STATISTICAL CHARACTERISTICS BY CONE EFFECT IN A SUPERSONIC BOUNDARY LAYER

通过直接数值模拟,计算了空间模式下,来流马赫数为2.5,半锥角为5°,零攻角的绝热钝锥湍流边界层,研究了湍流的统计特性,并把结果与超音速平板湍流边界层和马赫数为6的高超音速钝锥湍流边界层的结果进行了比较,重点定量地考察了锥体效应对边界层湍流统计特性的影响.研究发现,锥体效应对平均温度剖面以及压缩性的影响是显著的;而其它统计量,比如速度壁面律、雷诺应力的分布和湍动能各项的贡献等,受锥体效应的影响很小.

A spatial direct numerical simulation （DNS） was performed to study the turbulent statistical characteristics in the turbulent boundary layer on a blunt cone with an adiabatic wall at an oncoming Mach 2.5, zero angle of attack and the cone semi-angle of 5° in this paper. The results were compared with the simulated cases of the supersonic turbulent boundary layer over a flat plate and the hypersonic turbulent boundary layer on a blunt cone at Mach 6, suggesting the influence of the turbulent statistics with the cone effect. The results showed that, the cone effect is significant on the mean temperature profile and the compressibility, but unimportant on the scaling velocity law, the distribution of Reynolds stress and the budget of turbulent kinetic energy.