摘要
针对高超声速湍流边界层开展了直接数值模拟研究,对高温气体效应与湍流的耦合作用机理进行了分析。研究表明,高温气体效应使边界层内平均温度显著降低,平均密度显著升高。对于湍流脉动量,高温气体效应对温度脉动有较强的抑制作用,而对流向及壁面法向速度脉动和密度脉动的影响趋势在近壁面区域和边界层外层是相反的。在近壁面区域,流向和壁面法向速度脉动和密度脉动都被增强,而在边界层外层,高温气体效应则会抑制该速度脉动和密度脉动。在整个边界层内,高温气体效应使展向速度脉动降低。对于边界层内的雷诺应力,在y+>500区域,高温气体效应会使雷诺应力值减小;而在y+<500的近壁面区域内,高温气体效应明显增大了雷诺应力值,进而增强了湍流引起的动量交换,从而使壁面处速度梯度增加,最终使摩擦阻力增加。对壁面热流,高温气体效应引起的较明显的平均温度降低使得壁面温度梯度降低,导致热流降低。高温气体效应使壁面平均压强和脉动压强均增加。
In this paper,direct numerical simulation(DNS)studies are carried out on the hypersonic and high-enthalpy turbulent boundary layer,and the coupling mechanism of the high-temperature gas effect and turbulence is analyzed.It is found that the high-temperature gas effect significantly reduces the mean temperature and increases the mean density in boundary layer,while reduce the temperature fluctuation.In the near-wall area,both the velocity fluctuation and density fluctuation are enhanced.But in the outer area of boundary layer,these turbulent fluctuations are suppressed by high-temperature gas effect.For the Reynolds stress,high-temperature gas effect decreases the Reynolds stress value in the area of y+>500 in boundary layer,while increases the Reynolds stress value in the region of y+<500,which in turn enhances the momentum exchange caused by turbulence.Thereby,skin friction is increased.The wall heat transfer is strengthened by high-temperature gas effect as well.Moreover,the high temperature gas effect increases both the mean pressure and the fluctuation pressure at wall.
作者
吴正园
莫凡
高振勋
蒋崇文
李椿萱
WU Zhengyuan;MO Fan;GAO Zhenxun;JIANG Chongwen;LEE Chunhian(Beihang University,Beijing 100191,China;Laboratory of Aero-thermal Protection Technology for Aerospace Vehicles,China Aerospace Science and Technology Corporation,Beijing 100191,China)
出处
《空气动力学学报》
CSCD
北大核心
2020年第6期1111-1119,1128,I0003,共11页
Acta Aerodynamica Sinica
基金
国家数值风洞工程
国家自然科学基金(11872094)。
关键词
高温气体效应
湍流边界层
直接数值模拟
多物理场耦合
high temperature gas effect
turbulent boundary layer
direct numerical simulation
multiphysics coupling
