The present work is devoted to the assessment of a low-noise turbulence generation methodology used to produce boundary layer with three-dimensional resolved turbulence at the exit of a jet nozzle to reproduce experimental conditions. The method relies on the use of roughness elements introduced in the computational domain with Immersed Boundary Conditions and ZDES mode 3 (Wall Modelled LES branch of ZDES). The simulation of a round jet at M = 0.9 and Reynold number 10⁶ with turbulence generation is compared to a simulation with no resolved turbulence in the nozzle boundary layer using ZDES mode 2. The behaviour of the boundary layer downstream of the roughness elements inside the nozzle is scrutinized using two grids. The turbulence generation method combined with ZDES mode 3 produces satisfying levels of resolved turbulence at the nozzle exit. The early stages of the shear layer development are modified by the ZDES mode 3 simulations providing an initially turbulent shear layer. On the other hand, the ZDES mode 2 simulations, with a turbulent mean exit velocity profile but no resolved turbulence, display a short area of strong shear layer instabilities leading to the quick development of three-dimensional turbulence in the mixing layer. The present results give insights on the level of turbulent modelling of the nozzle boundary layer needed depending on the purposes of the jet flow simulations considered.

本工作致力于评估低噪声湍流产生方法，该方法用于在喷嘴出口处产生具有三维分辨湍流的边界层，从而再现实验条件。该方法依靠使用在计算域中引入的具有浸入边界条件和ZDES模式3（ZDES的Wall模型LES分支）的粗糙度元素。M  = 0.9和雷诺数10 ⁶的圆形射流的仿真使用ZDES模式2，将产生湍流的模拟与在喷嘴边界层中没有解析湍流的模拟进行比较。使用两个网格来检查喷嘴内部粗糙度元素下游的边界层的行为。结合ZDES模式3的湍流产生方法在喷嘴出口产生令人满意的水平湍流。剪切层发展的早期阶段通过提供初始湍流剪切层的ZDES模式3仿真进行了修改。另一方面，具有平均湍流出口速度分布但没有解析湍流的ZDES模式2模拟显示出短面积的强剪切层不稳定性，从而导致混合层中三维湍流的快速发展。