Droplet impact on a solid surface occurs in many natural phenomena and industrial applications such as raindrop impact on the ground, drip irrigation, spray cooling, spray coating, inkjet printing, etc. Importantly, in several cases such as aerosol transfer from the sea, oxygen dissolution, and thermally sprayed coatings the impinging droplets contain air bubble dealing with liquid-bubble-solid interaction. These hollow droplets upon impacting on the target surface, due to their controllable weight and embedded medium, control the splat properties by triggering the cavitation and releasing the inner substance. To better understand the flattening process of a hollow droplet, in this work a comprehensive experimental and numerical study is performed on water and glycerol droplets impacting on a rigid surface. The experiments are repeated on different types of surfaces including aluminum, sand-blasted steel, and superhydrophobic. The results show that the mechanisms of the post-impact process of hollow droplets are different from those of dense droplets in several aspects. We study the role of surface wettability, liquid properties, and impact velocity on the droplet flattening process. In the numerical work, we compare pressure contours and velocity vectors for dense and hollow droplets that provide an in-depth insight through the formation of splat and counter jets.

液滴对固体表面的撞击发生在许多自然现象和工业应用中，例如雨滴撞击地面、滴灌、喷雾冷却、喷涂、喷墨打印等。 重要的是，在几种情况下，例如来自海洋的气溶胶转移、氧气溶解和热喷涂涂层撞击的液滴含有气泡，处理液-泡-固相互作用。这些空心液滴在撞击目标表面时，由于其可控的重量和嵌入的介质，通过触发空化和释放内部物质来控制飞溅特性。为了更好地理解空心液滴的压扁过程，在这项工作中，对撞击刚性表面的水和甘油液滴进行了全面的实验和数值研究。这些实验在不同类型的表面上重复进行，包括铝、喷砂钢和超疏水表面。结果表明，空心液滴的后撞击过程机制在几个方面与致密液滴不同。我们研究了表面润湿性、液体性质和冲击速度对液滴压平过程的作用。在数值工作中，我们比较了稠密和空心液滴的压力轮廓和速度矢量，通过形成喷溅和反射流提供了深入的洞察力。和冲击速度对液滴平整过程的影响。在数值工作中，我们比较了稠密和空心液滴的压力轮廓和速度矢量，通过形成喷溅和反射流提供了深入的洞察力。和冲击速度对液滴平整过程的影响。在数值工作中，我们比较了稠密和空心液滴的压力轮廓和速度矢量，通过形成喷溅和反射流提供了深入的洞察力。