Interaction between fuel and air in a combustion chamber is one of the main drivers of the mixing process. Experimentally, flow visualizations are limited by high droplet density in the spray. Numerically, the ability of large eddy simulations (LES) to resolve large scales of flow offers good perspectives on capturing flow structures issued from the interaction between the Lagrangian (fuel droplets) and Eulerian (ambient gas) phases. This study examined these interactions first during a single injection using 3D and 2D criteria for both phases. As for the 3D criteria, the spray shape was analyzed in parallel to the Q-criteria applied to the Eulerian phase, making it possible to relate the spray deformations to some specific Eulerian structures. Secondly, 2D criteria were the fuel mass-fraction field and Eulerian streamlines, both taken in the mid-plane of the spray. This last analysis allows for identifying certain mechanisms involved in the Eulerian phase's structure generation and relates it to high fuel-concentration areas in the fuel mass-fraction visualizations.

燃烧室内的燃料与空气之间的相互作用是混合过程的主要驱动因素之一。实验上，流量可视化受到喷雾中高液滴密度的限制。在数值上，大涡流模拟（LES）解析大尺度流动的能力为捕获由拉格朗日相（燃料滴）和欧拉相（环境气相）之间的相互作用而产生的流动结构提供了良好的前景。这项研究首先在两个阶段使用3D和2D标准检查一次注射中的这些相互作用。至于3D准则，喷雾形状与应用于欧拉相的Q准则平行进行了分析，从而可以将喷雾变形与某些特定的欧拉结构联系起来。其次，二维标准是燃料质量分数场和欧拉流线，两者都在喷雾的中平面。最后的分析允许确定欧拉相结构生成中涉及的某些机制，并将其与燃料质量分数可视化中的高燃料浓度区域相关联。