In this work, the post-impact drop motions of the rebound regime on inclined hydrophobic surfaces are investigated using a numerical technique. The effects of impact velocity ($V_i$ = 0.5–1.5 m/s), drop diameter ($D_0$ = 1.0–2.5 mm), surface wettability (${\theta }_{eq}$ = 120°–160°), and inclined angle ($\alpha$ = 0°–80°) on the post-impact regimes, contact time ($t_c$) and spreading time ($t_s$), nondimensionalized maximum spreading diameter (${D_{s\_\text{max}}}^{*}$), and drop displacement prior to the rebound ($l_{d\_\mathit{final}}$) are examined and analyzed, some of which exhibit markedly different outcomes at $\alpha$ = 80° compared to $\alpha \le$ 60°. It has been discovered that the rebound regime occurs in most impact conditions at ${\theta }_{eq}$ = 160° and 140° but transitions to sliding for all $\alpha$ = 80° cases at ${\theta }_{eq}$ = 120°. When $\alpha \le$ 60°, $t_c$ and $t_s$ of ${\theta }_{eq}$ = 160° and 140° are very close and hardly affected by $V_i$ and $\alpha$, which are generally smaller than those of $\alpha$ = 80°, resulting from the rapid decline of the normal impact velocity that diminishes drop deformation and prolongs drop sliding motion. ${D_{s\_\text{max}}}^{*}$ is barely influenced by ${\theta }_{eq}$ but increases with $V_i$ and $D_0$ and decreases when $\alpha$ increases owing to a greater normal inertial force. $l_{d\_\mathit{final}}$ generally increases with $V_i$, $D_0$, and $\alpha$ but with different mechanisms. More importantly, the nondimensionalized parameters ${t_c}^{*}$, ${D_{s\_\text{max}}}^{*}$, and ${l_{d\_\mathit{final}}}^{*}$ are found to scale with the normal or tangential Weber numbers according to the power law, while the exponents vary with ${\theta }_{eq}$ and $\alpha$.

中文翻译：

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不同润湿性的倾斜疏水表面液滴回弹的冲击后动力学

在这项工作中，使用数值技术研究了倾斜疏水表面上回弹状态的冲击后下降运动。冲击速度的影响（${伏}_{\mathrm{一世}}$ = 0.5–1.5 m/s)，液滴直径 ($D_0$ = 1.0–2.5 毫米），表面润湿性（${\theta }_{\mathrm{电子}q}$ = 120°–160°) 和倾斜角 ($\alpha$ = 0°–80°）在后撞击状态，接触时间（${吨}_C$) 和传播时间 (${吨}_{秒}$), 无量纲化最大铺展直径 (${D_{秒\_\text{最大限度}}}^{*}$)，以及回弹前的下落位移 (${升}_{d\_\mathit{最后}}$) 被检查和分析，其中一些表现出明显不同的结果 $\alpha$ = 80° 与 $\alpha \le$60°。已经发现，回弹机制发生在大多数冲击条件下${\theta }_{\mathrm{电子}q}$ = 160° 和 140° 但过渡到滑动 $\alpha$ = 80° 情况下 ${\theta }_{\mathrm{电子}q}$= 120°。什么时候$\alpha \le$ 60°， ${吨}_C$ 和 ${吨}_{秒}$ 的 ${\theta }_{\mathrm{电子}q}$ = 160° 和 140° 非常接近，几乎不受 ${伏}_{\mathrm{一世}}$ 和 $\alpha$，它们通常小于 $\alpha$ = 80°，这是由于法向冲击速度的快速下降而导致的，这会减少液滴变形并延长液滴滑动运动。 ${D_{秒\_\text{最大限度}}}^{*}$ 几乎不受影响 ${\theta }_{\mathrm{电子}q}$ 但随着 ${伏}_{\mathrm{一世}}$ 和 $D_0$ 并且当 $\alpha$ 由于较大的法向惯性力而增加。 ${升}_{d\_\mathit{最后}}$ 一般随着 ${伏}_{\mathrm{一世}}$, $D_0$， 和 $\alpha$但具有不同的机制。更重要的是，无量纲化参数${{吨}_C}^{*}$, ${D_{秒\_\text{最大限度}}}^{*}$， 和 ${{升}_{d\_\mathit{最后}}}^{*}$ 发现根据幂律与法向或切向韦伯数成比例，而指数随 ${\theta }_{\mathrm{电子}q}$ 和 $\alpha$.