Large eddy simulation (LES) coupled with Lagrangian particle simulation (LPS) is applied to investigate high‐speed turbulent reacting flows. Here, LES solves a velocity field while LPS solves scalar transport equations with notional particles. Although LPS does not require sub‐grid scale models for chemical source terms, molecular diffusion has to be modeled by a so‐called mixing model, for which a mixing volume model (MVM), that is originally proposed for an inert scalar in incompressible flow, is extended to reactive scalars in compressible flows. The extended model is based on a relaxation process toward the average of nearby notional particles and assumes a common mixing timescale for all species. LES/LPS with the MVM is applied to a temporally‐evolving compressible turbulent planar jet with an isothermal reaction and is tested by comparing the results with direct numerical simulation (DNS). The results show that LES/LPS well predicts the statistics of mass fractions. As the jet Mach number increases, the reaction progress delays due to the delayed jet development. This Mach number dependence is also well reproduced in LES/LPS. The mean molecular diffusion term of the product calculated as a function of its mass fraction also agrees well between LES/LPS and DNS. An important parameter for the MVM is the distance among particles, for which the requirement for accurate prediction is presented for the present test case. LES/LPS with the MVM is expected to be a promising method for investigating compressible turbulent reactive flows at a moderate computational cost.

中文翻译：

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化学反应可压缩湍流平面射流的混合大涡模拟和拉格朗日模拟

大涡模拟（LES）与拉格朗日粒子模拟（LPS）相结合用于研究高速湍流反应流。这里，LES 求解速度场，而 LPS 求解具有概念粒子的标量输运方程。虽然 LPS 不需要化学源项的亚网格尺度模型，但分子扩散必须通过所谓的混合模型进行建模，其中混合体积模型 (MVM) 最初是针对不可压缩流中的惰性标量提出的，扩展到可压缩流中的反应标量。扩展模型基于对附近概念粒子平均值的松弛过程，并假设所有物种都有共同的混合时间尺度。具有 MVM 的 LES/LPS 应用于具有等温反应的时间演化可压缩湍流平面射流，并通过将结果与直接数值模拟 (DNS) 进行比较来进行测试。结果表明，LES/LPS 很好地预测了质量分数的统计量。随着喷射马赫数的增加，由于喷射发展的延迟，反应进程也会延迟。这种马赫数依赖性在 LES/LPS 中也得到了很好的再现。作为其质量分数的函数计算的产物的平均分子扩散项在 LES/LPS 和 DNS 之间也非常一致。MVM 的一个重要参数是粒子之间的距离，对于当前的测试用例提出了准确预测的要求。带有 MVM 的 LES/LPS 有望成为一种以适度的计算成本研究可压缩湍流反应流的有前途的方法。