Abstract In this paper, air cavity and Worthington jet formations due to the entrance of a hydrophilic steel sphere into three different target liquids are studied. The liquids are water, silicone oil and silicone oil film on water. A high-speed camera is used to observe cavity and jet formations, and the resulting data is used to measure important parameters such as jet height, deep-seal time and deep-seal depth of the cavity. It was observed that no cavity forms after a hydrophilic sphere enters water. However, when a very thin layer of silicone oil is put on the water surface, a large air cavity and Worthington jet were observed. The results observed did not strongly vary with oil film thickness for the range studied in this work, and that as long as there is a layer of oil on water that wets the sphere surface before its entrance, an air cavity and jet will form. Additionally, an energy analysis is done for better understanding how kinetic energy of the sphere is transferred to the fluid. In the case of an oil film on water, the sphere lost its kinetic energy much more than when the target liquid was silicone oil or water. As a result, the fluid gained a significant amount of energy to form an air cavity which did not happen without oil film, and a Worthington jet of greater maximum height than the other two cases. Kinetic, surface and potential energies of the Worthington jet as it forms and reaches its peak are studied as well.

中文翻译：

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由球体落入水面上的油膜引起的空腔和沃辛顿射流形成的实验研究

摘要 本文研究了由于亲水钢球进入三种不同目标液体而形成的气腔和沃辛顿射流。液体是水、硅油和水面上的硅油膜。高速摄像机用于观察空腔和射流的形成，所得数据用于测量空腔的射流高度、深封时间和深封深度等重要参数。观察到在亲水球体进入水中后没有空腔形成。然而，当在水面上涂上一层很薄的硅油时，观察到一个大的气腔和沃辛顿射流。在这项工作中研究的范围内，观察到的结果不会随油膜厚度发生很大变化，只要水面上有一层油在球体进入之前润湿球体表面，将形成气腔和射流。此外，还进行了能量分析，以更好地了解球体的动能如何转移到流体中。在水面上有油膜的情况下，球体失去的动能比目标液体是硅油或水时要大得多。结果，流体获得了大量能量以形成没有油膜时不会发生的气腔，以及比其他两种情况更大的最大高度的沃辛顿射流。还研究了沃辛顿喷流形成并达到峰值时的动能、表面能和势能。当目标液体是硅油或水时，球体失去的动能要多得多。结果，流体获得了大量能量以形成没有油膜时不会发生的气腔，以及比其他两种情况更大的最大高度的沃辛顿射流。还研究了沃辛顿喷流形成并达到峰值时的动能、表面能和势能。当目标液体是硅油或水时，球体失去的动能要多得多。结果，流体获得了大量能量以形成没有油膜时不会发生的气腔，以及比其他两种情况更大的最大高度的沃辛顿射流。还研究了沃辛顿喷流形成并达到峰值时的动能、表面能和势能。