自由落体对变液和冲击物表面条件下深层液池的影响
Summary
该协议演示了自由落体进水实验的基本实验结构。讨论了用可渗透织物改变液体表面的方法、化学非润湿球体的制备以及飞溅可视化和数据提取的步骤。
Abstract
球体对清洁水的垂直影响一直是许多水进入调查的主题, 其特征是腔的形成、飞溅冠的提升和沃辛顿的喷射稳定性。在这里, 我们建立了实验协议, 以检查飞溅动力学时, 光滑的自由落体球不同的润湿性, 质量和直径影响一个深液池的自由表面修改薄渗透织物和液体表面活性剂。进水调查为研究复杂流体力学提供了可访问的、易于组装和执行的实验。我们在此提出了一个可调谐的协议, 用于表征飞溅高度、流量分离指标和冲击运动学, 以及如果重现我们的方法可能会获得的代表性结果。当特征飞溅尺寸保持在约0.5 米以下时, 该方法适用。然而, 该协议可以适应更大的冲击释放高度和冲击速度, 这预示着将结果转化为海军和工业应用的好兆头。
Introduction
固体物体对深液池1的垂直撞击所产生的飞溅动力学特性适用于军事、海军和工业应用, 如弹道导弹进水和海面着陆 2, 3,4,5。第一次进水研究是在一个多世纪前的 6、7日进行的。在这里, 我们建立了明确的深入协议和最佳做法, 以便在进水调查中取得一致的结果。为了辅助有效的实验设计, 提出了一种卫生条件维护、界面条件改变、无量纲参数控制、冲击表面化学修饰、飞溅运动学可视化等方法。
自由落体亲水球体对静止流体的垂直影响在低速时没有空气堵塞的迹象.我们发现, 在流体表面上放置薄型可穿透织物会导致空腔形成, 原因是强制流动分离1。表面上少量的织物放大了在一系列中等韦伯数上的飞溅, 而足够的分层衰减飞溅, 因为球体克服了流体入口1的阻力。在本文中, 我们解释了适用于确定材料强度对亲水球进水的影响的协议。
从疏水冲击器形成的凹槽显示了一个发育良好的飞溅冠的提升, 其次是原始射流在地表上方的突起, 而与他们喜欢水的对应者相比。在这里, 我们提出了一种方法, 以实现防水通过化学改性的水面亲水球。
随着高速摄像机的出现, 飞溅可视化和表征变得更加容易实现。即使如此, 该领域的既定标准也要求使用与旅行的主轴正交的单个相机。我们表明, 使用额外的高速摄像头的架空视图是必要的, 以判断球体罢工的预期位置。
Protocol
1. 配置垂直冲击的实验 将尺寸约为60厘米 x30 厘米 x 36 厘米 (长度 x 重量 x 深度) 的透明水箱填充32升的水, 并在容器内垂直安装仪表尺 (“视觉刻度”), 使底座位于流体顶部, 如图1a 所示。注: 罐的深度和宽度必须大于实验中使用的最大球体直径的 20倍, 以确保墙体效应可以忽略不计.比这里描述的更高的进入速度将需要更大的坦克深度。第7节讨论了用?…
Representative Results
这一既定协议允许遵守沃辛顿喷气式飞机所产生的垂直撞击范围内的韦伯数 , 如图2c 所示。这些结果发表在 watson 等人的文章1 中, 可供用于生成本文所示数据的确切实验条件参考。我们关注的是在自由液体表面上方突出的流体的窄拉长膜。在图 3中, 我们展示了?…
Discussion
该协议描述了在深层液池中调查自由落体球的实验设计和最佳实践。我们首先强调配置垂直影响实验所需的步骤。使用足够大的飞溅区域创建理想的飞溅环境非常重要, 这样墙体效果可以忽略不计9, 并且需要适当的视觉尺度来提取运动学12、13、14 , 15,16,<…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
作者希望感谢中佛罗里达大学工程与计算机科学学院 (cecs) 为这一项目提供的资金, 乔舒亚·博姆和克里斯·苏奇克为飞溅图像和尼古拉斯·史密斯提供了宝贵的反馈。
Materials
| 3D Printer | FlashForge | Creator Pro | Dual Extrusion |
| Alcohol | Swan | M314 | 99% Isopropyl |
| BNC Cables | Thorlabs | 2249-C-24 | |
| Caliper | Anytime Tools | 203185 | Dial |
| Camera | Photron | Mini AX-100 | 16GB Ram |
| Computer | Dell | Windows 7 Pro | |
| Fabric | Georgia Pacific | 19378 | Toilet Paper |
| Fabric | Kleenex | 10036000478478 | Tissue |
| Laser Cutter | Glowforge | Basic | |
| Lights | GS Vitec | LT-V9-15 | Multi-LED |
| Microscope | Keyence | VHX-900F | Digital |
| Retort Stand | VWR | VWRF08530.083 | |
| Router | ASUS | RT-N12 | Off Network |
| Ruler | Westcott | 10432 | Meter Ruler |
| Software | Open-Source | Tracker | Video Analysis |
| Software | Photron | Fastcam Viewer | Video Recording |
| Sphere | Amazon | 8DELSET | Delrin |
| Spray | Rust-Oleum | 274232 | Water Repelling |
| Surfactant | Dawn | 37000973782 | Liquid Soap |
| Surfactant | USP Kosher | 5 Gallons | Glycerin |
| Tensile Tester | MTS | Model 42 | |
| Trigger Switch | Custom Made | ||
| Water Tank | Mr. Aqua | MA-730 | Non-Tempered Glass |
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Citazione di questo articolo
Watson, D. A., Stephen, J. L., Dickerson, A. K. Impacts of Free-falling Spheres on a Deep Liquid Pool with Altered Fluid and Impactor Surface Conditions. J. Vis. Exp. (144), e59300, doi:10.3791/59300 (2019).