The sensitivity of turbulent dynamics in spatially evolving mixing layers to small skew angles $\unicode[STIX]{x1D703}$ is investigated via direct numerical simulation. Angle $\unicode[STIX]{x1D703}$ is a measure of the lack of parallelism between the two asymptotic flows, whose interaction creates the turbulent mixing region. The analysis is performed considering a large range of values of the shear intensity parameter $\unicode[STIX]{x1D6FC}$ . This two-dimensional parameter space is explored using the results of a database of 18 direct numerical simulations. Instantaneous fields as well as time-averaged quantities are investigated, highlighting important mechanisms in the emergence of turbulence and its characteristics for this class of flows. In addition, a stochastic approach is used in which $\unicode[STIX]{x1D703}$ and $\unicode[STIX]{x1D6FC}$ are considered as random variables with a given probability distribution. The response surfaces of flow statistics in the parameter space are built through non-intrusive generalized polynomial chaos. It is found that variations of the parameter $\unicode[STIX]{x1D6FC}$ have a primary effect on the growth of the mixing region. A secondary effect associated with $\unicode[STIX]{x1D703}$ is observed as well. Higher values for the skew angle are responsible for a rapid increase in growth of the inlet structures, enhancing the development of the mixing region. The impact on the turbulence features and, in particular, on the Reynolds stress tensor is also significant. A modification of the normalized diagonal components of the Reynolds stress tensor due to $\unicode[STIX]{x1D703}$ is observed. In addition, the interaction between the parameters $\unicode[STIX]{x1D703}$ and $\unicode[STIX]{x1D6FC}$ is here the governing element.

通过直接数值模拟研究了空间演化混合层中湍流动力学对小偏角 $ \ unicode [STIX] {x1D703} $的敏感性 。角度 $ \ unicode [STIX] {x1D703} $ 是对两个渐近流之间缺乏并行性的度量，它们的相互作用会创建湍流混合区域。考虑剪切强度参数 $ \ unicode [STIX] {x1D6FC} $ 的较大范围的值进行分析 。使用18个直接数值模拟的数据库结果来探索此二维参数空间。对瞬时场和时间平均量进行了研究，突出了湍流出现的重要机理及其对于此类流动的特性。另外，使用一种随机方法，其中将 $ \ unicode [STIX] {x1D703} $ 和 $ \ unicode [STIX] {x1D6FC} $ 视为具有给定概率分布的随机变量。参数空间中流量统计的响应面是通过非侵入式广义多项式混沌构建的。发现参数 $ \ unicode [STIX] {x1D6FC} $的变体 对混合区域的生长有主要影响。还观察到与 $ \ unicode [STIX] {x1D703} $ 相关的次级影响。较高的偏斜角值会导致入口结构的增长迅速增加，从而增强混合区域的发展。对湍流特征，特别是对雷诺应力张量的影响也很重要。观察到由于 $ \ unicode [STIX] {x1D703} $ 导致的雷诺应力张量的归一化对角线分量的修改。另外，参数 $ \ unicode [STIX] {x1D703} $ 和 $ \ unicode [STIX] {x1D6FC} $ 之间的交互在这里是控制元素。