Direct simulation of the turbulent boundary layer along a compression ramp at M = 3 and Reθ = 1685
Direct simulation of the turbulent boundary layer along a compression ramp at M = 3 and Reθ = 1685
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DOI：
10.1017/s0022112000001257
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发表时间：
2000-10
影响因子：
3.7
通讯作者：
N. Adams
中科院分区：
文献类型：
--
作者：
N. Adams
本文采用直接数值模拟方法，研究了在来流马赫数M = 3，雷诺数Reθ = 1685时，沿偏转角为18°的压缩斜面的湍流边界层沿着与来流量和来流平均动量厚度的关系。在广义坐标系中求解质量、动量和能量守恒方程，对流通量采用5阶混合紧致有限差分ENO格式，扩散通量采用6阶中心紧致有限差分格式。对于时间推进，使用三阶Runge-Kutta格式。计算区域采用约15 × 106个网格点进行离散。紊流流入数据由单独的零压力梯度边界层模拟提供。为了进行统计分析，在大约385个特征时间尺度δ0/U∞（由入流时的平均边界层厚度和自由流速度定义）内对气流进行600次采样。诊断表明，流场的数值表示是足够好地解决。在拐角附近，形成了一个小的分离流区.激波运动被限制在平均边界层厚度的10%以下。激波在其平均位置附近轻微振荡，其频率与来流边界层的破裂频率相似。由于激波-边界层相互作用，湍流脉动被显著放大。最大应力放大约4倍。湍流正应力和剪应力被不同程度地放大，导致结构参数的变化。可压缩性影响拐角附近的相互作用区域以及拐角下游再附着后的松弛期间的湍流结构。在这些地区，压力波动的相关性显着增强。强雷诺类比，这表明速度和温度波动之间的完美相关性被发现是无效的相互作用区域。
The turbulent boundary layer along a compression ramp with a deflection angle of 18° at a free-stream Mach number of M = 3 and a Reynolds number of Reθ = 1685 with respect to free-stream quantities and mean momentum thickness at inflow is studied by direct numerical simulation. The conservation equations for mass, momentum, and energy are solved in generalized coordinates using a 5th-order hybrid compact- finite-difference-ENO scheme for the spatial discretization of the convective fluxes and 6th-order central compact finite differences for the diffusive fluxes. For time advancement a 3rd-order Runge–Kutta scheme is used. The computational domain is discretized with about 15 × 106 grid points. Turbulent inflow data are provided by a separate zero-pressure-gradient boundary-layer simulation. For statistical analysis, the flow is sampled 600 times over about 385 characteristic timescales δ0/U∞, defined by the mean boundary-layer thickness at inflow and the free-stream velocity. Diagnostics show that the numerical representation of the flow field is sufficiently well resolved. Near the corner, a small area of separated flow develops. The shock motion is limited to less than about 10% of the mean boundary-layer thickness. The shock oscillates slightly around its mean location with a frequency of similar magnitude to the bursting frequency of the incoming boundary layer. Turbulent fluctuations are significantly amplified owing to the shock–boundary-layer interaction. Reynolds-stress maxima are amplified by a factor of about 4. Turbulent normal and shear stresses are amplified differently, resulting in a change of the structure parameter. Compressibility affects the turbulence structure in the interaction area around the corner and during the relaxation after reattachment downstream of the corner. Correlations involving pressure fluctuations are significantly enhanced in these regions. The strong Reynolds analogy which suggests a perfect correlation between velocity and temperature fluctuations is found to be invalid in the interaction area.