标题： 强迫两相湍流的定态 显示英文标题

标题： Stationary states of forced two-phase turbulence

摘要： 在本工作中，我们对强制两相各向同性湍流进行了数值模拟，以研究两相混合物的稳态。我们首先提出了三种不同的方法来强制两相湍流，以保持恒定的（a）混合物动能，（b）混合物动能+表面能，以及（c）各相的动能，并研究它们对系统最终稳态的影响。我们表明，强制两相系统消除了在两相湍流模拟中第二相初始化时的任意性。接下来，我们研究了在不同密度比（$10^{-3}$到$10^3$）和粘度比（$10^{-3}$到$10^3$）、空隙率（稀释到密集区域）以及韦伯数（破裂和非破裂区域）下，两相混合物在稳态下的全局统计特性。我们采用了一种空间滤波方法，适用于不可压缩/可压缩两相流动的一般情况，以计算各相的能量谱并研究湍流动能在不同尺度上的分布。我们发现界面表现得像一个软墙，抑制了涡旋在分散相内部的适应。最后，我们表明，在相同的载流相全局条件下，气泡和液滴表现出不同的湍流特征，气泡内部的湍流强度更高，而液滴则表现出类似固体颗粒的弹道行为。这项研究为稳态两相湍流奠定了基础，可用于进一步分析以及开发更大规模两相湍流模拟的亚网格尺度模型。 显示英文摘要

摘要： In this work, we perform numerical simulations of forced two-phase isotropic turbulence to study the stationary states of a two-phase mixture. We first formulate three different approaches to force a two-phase turbulent flow that maintains a constant (a) mixture kinetic energy, (b) mixture kinetic energy + surface energy, and (c) individual phase kinetic energy, and study their effect on the final stationary state of the system. We show that forcing the two-phase system eliminates the arbitrariness associated with the initialization of the second phase in two-phase turbulence simulations. Next, we study the global statistics of the two-phase mixture in the stationary state for varying density ratios ($10^{-3}$ to $10^3$) and viscosity ratios ($10^{-3}$ to $10^3$), void fraction (dilute to dense regimes), and Weber numbers (breakup and non-breakup regimes). We utilize a spatial filtering approach, that is applicable for the general case of incompressible/compressible two-phase flows, to compute the energy spectra of each of the phases and study the turbulent kinetic energy distribution across scales. We find that the interface behaves as a soft wall, inhibiting the accommodation of eddies inside the dispersed phase. Finally, we show that bubbles and drops exhibit different turbulent characteristics for the same global conditions of the carrier phase, with bubbles exhibiting higher turbulent intensities inside them and droplets behaving ballistically, similar to solid particles. This study acts as a foundational work on stationary two-phase turbulence, which can be used for further analysis and the development of subgrid-scale models for larger-scale simulations of two-phase turbulent flows.