We report that the splash created by a solid impactor moving into a bed of granular media depends sensitively on the temperature of the granular bed. Granules were poured loosely into an open-top container and then heated from below, and a metal ball was then dropped into the hot granular bed. High-speed video experiments reveal that the size and average velocity of the resulting granular splash both decrease significantly as the temperature increases. Complementary experiments show that the composition of the surrounding gas also strongly affects the splash dynamics but that the gas pressure and corresponding density have no significant effect. We interpret these observations in terms of two physical effects: the influence of the temperature- and composition-dependent gas viscosity on the ejecta drag force, and an enhanced static strength within the bed caused by thermal expansion of the granules. Taken together, the results indicate that temperature plays a greater role in granular splashing than previously suspected.

中文翻译：

---

撞击加热的颗粒床时飞溅

我们报告说，由固体撞击器移入颗粒介质床所产生的飞溅物敏感地取决于颗粒床的温度。将颗粒松散地倒入敞口容器中，然后从下方加热，然后将金属球滴入热的颗粒床中。高速视频实验表明，所产生的颗粒状飞溅的大小和平均速度都随温度升高而显着降低。补充实验表明，周围气体的组成也强烈影响飞溅动力学，但是气体压力和相应的密度没有显着影响。我们用两种物理效应来解释这些观察结果：取决于温度和成分的气体粘度对喷射阻力的影响，以及由于颗粒的热膨胀而导致的床内静态强度的提高。两者合计，结果表明温度在颗粒飞溅中的作用比以前怀疑的要大。