Abstract We use direct numerical simulation based on the level contour reconstruction method to investigate head-on droplet collisions with dry, stationary, spherical particles. Three important impact parameters are varied over broad ranges: Weber number (4 ≤ We ≤ 150), surface wettability (20° ≤ θeqi ≤ 160°), and droplet-to-particle-size ratio (1/3 ≤ Ω ≤ 2), leading to a total of 225 collision scenarios being examined. Seven collision outcomes are identified: deposition, partial rebound, complete rebound, complete coating, gravity disintegration, momentum disintegration, and splashing, and are represented in outcome regime maps. The first six outcomes are categorized into two cases: the partial-coating case (deposition, partial rebound, and complete rebound for larger particles) and the full-coating case (complete coating, gravity disintegration, and momentum disintegration for smaller particles), with a clear boundary separating the two cases in parameter space. The partial-coating case is characterized by maximum spreading and a subsequent recoiling that depends strongly on wettability. Conversely, the full-coating case involves complete initial wetting of the particle and the following dynamics is strongly governed by impact velocity. Detailed interaction mechanisms of each outcome scenario are also presented. Furthermore, three important quantitative parameters (i.e., film thickness, maximum spreading diameter, and coating time) are analyzed in detail.

中文翻译：

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液滴与静止球形粒子碰撞的直接数值模拟：结果的综合图

摘要 我们使用基于水平轮廓重建方法的直接数值模拟来研究与干燥、静止、球形颗粒的正面液滴碰撞。三个重要的影响参数在很宽的范围内变化：韦伯数 (4 ≤ We ≤ 150)、表面润湿性 (20° ≤ θeqi ≤ 160°) 和液滴粒径比 (1/3 ≤ Ω ≤ 2) ，导致总共检查了 225 个碰撞场景。确定了七种碰撞结果：沉积、部分回弹、完全回弹、完全涂层、重力分解、动量分解和飞溅，并在结果状态图中表示。前六项结果分为两种情况：部分包衣情况（较大颗粒的沉积、部分回弹和完全回弹）和全包衣情况（完全包衣、重力崩解、和较小粒子的动量分解），在参数空间中用清晰的边界将两种情况分开。部分涂层情况的特点是最大程度的铺展和随后的反卷，这在很大程度上取决于润湿性。相反，全涂层情况涉及粒子的完全初始润湿，随后的动力学强烈地受冲击速度控制。还介绍了每个结果场景的详细交互机制。此外，详细分析了三个重要的定量参数（即膜厚、最大铺展直径和涂布时间）。部分涂层情况的特点是最大程度的铺展和随后的反卷，这在很大程度上取决于润湿性。相反，全涂层情况涉及粒子的完全初始润湿，随后的动力学强烈地受冲击速度控制。还介绍了每个结果场景的详细交互机制。此外，详细分析了三个重要的定量参数（即膜厚、最大铺展直径和涂布时间）。部分涂层情况的特点是最大程度的铺展和随后的反卷，这在很大程度上取决于润湿性。相反，全涂层情况涉及粒子的完全初始润湿，随后的动力学强烈地受冲击速度控制。还介绍了每个结果场景的详细交互机制。此外，详细分析了三个重要的定量参数（即膜厚、最大铺展直径和涂布时间）。