Studies of Liquid Interface Dynamics Using a Highly Characterized System

小行星9801844 这是一个利用液氦的低温物理研究项目，液氦是一种高度特征化的量子液体。 创新的声学和光学技术用于研究液体界面（表面）动力学，包括液体聚结，气泡夹带，液滴碰撞和类似现象。这些实验旨在测试或扩展目前在凝聚态物理学中正在开发的液体表面行为理论。主要的重点是液滴的影响和夹带气体的模式，认为负责产生水下噪声的机制。 虽然大多数现有的测量和理论模型都是针对水的，但拟议的实验将使用液氦，其高纯度和在广泛参数范围内精确控制的能力使其非常适合定量测试当前的流体动力学理论。液滴将与大量液体界面碰撞，并且在界面破裂处发生的快速变化的应力场将辐射声波，该声波将以10 ns的时间分辨率被检测到，接近分子水平的破裂时间尺度。该研究计划将为声学方法的研究生提供独特的培训机会，这是一个在当代物理学中经常被忽视的领域，涉及特殊的，往往是微妙的实验方法。这是一个基础项目，但结果可能与一系列实际情况有关，包括涉及泡沫和乳液的工业过程，商业混合器和喷雾器，超声波在医学中的应用，雨水产生的水下噪音，这在军事和环境监测中很重要，等。%这是一个利用液态氦的低温物理研究项目，液态氦是一种高度特征化的量子液体。 创新的声学和光学技术用于研究液体界面（表面）动力学，包括液体聚结，气泡夹带，液滴碰撞和类似现象。这些实验旨在测试或扩展目前在凝聚态物理学中正在开发的液体表面行为理论。主要的重点是液滴的影响和夹带气体的模式，认为负责产生水下噪声的机制。 虽然大多数现有的测量和理论模型都是针对水的，但拟议的实验将使用液氦，其高纯度和在广泛参数范围内精确控制的能力使其非常适合定量测试当前的流体动力学理论。液滴将与大量液体界面碰撞，并且在界面破裂处发生的快速变化的应力场将辐射声波，该声波将以10 ns的时间分辨率被检测到，接近分子水平的破裂时间尺度。该研究计划将为声学方法的研究生提供独特的培训机会，这是一个在当代物理学中经常被忽视的领域，涉及特殊的，往往是微妙的实验方法。这是一个基础项目，但其结果可能与一系列实际情况有关，包括涉及泡沫和乳液的工业过程，商业混合器和喷雾器，超声波在医学中的应用，雨水产生的水下噪音，这在军事和环境监测中很重要，等等。

9801844 Maynard This is a low temperature physics research project that makes use of liquid helium, a highly characterized quantum liquid. Innovative acoustic and optical techniques are used to study liquid interface (surface) dynamics, including liquid coalescence, bubble entrainment, droplet impact, and similar phenomena. The experiments are designed to test or extend theories of the behavior of liquid surfaces currently being developed in condensed matter physics. The main focus is on fluid droplet impact and the mechanisms of entrainment gases in the mode believed responsible for generation of underwater noise. While most existing measurements and theoretical models have been for water, the proposed experiments will make use of liquid helium, whose high purity and ability to be precisely and accurately controlled over a wide range of parameters make in uniquely suited for quantitatively testing current fluid dynamics theories. Drops will be made to collide with the bulk liquid interface, and the rapidly changing stress field occurring at the interface rupture will radiate sound waves which will be detected with a temporal resolution of 10 ns, approaching rupture time scales at the molecular level. The research program will provide unique training opportunities for graduate students in methods of acoustics, an area often overlooked in contemporary physics, and involving special, often-subtle experimental methods. This is a fundamental project but the results are potentially relevant to a range of practical situations including industrial processes involving foams and emulsions, in commercial blenders and sprayers, application of ultrasound in medicine, generation of underwater noise by rain, which is important in military and environmental monitoring, etc. %%% This is a low temperature physics research project that makes use of liquid helium, a highly characterized quantum liquid. Innovative acoustic and optical techniques are used to study liquid interface (surface) dynamics, including liquid coalescence, bubble entrainment, droplet impact, and similar phenomena. The experiments are designed to test or extend theories of the behavior of liquid surfaces currently being developed in condensed matter physics. The main focus is on fluid droplet impact and the mechanisms of entrainment gases in the mode believed responsible for generation of underwater noise. While most existing measurements and theoretical models have been for water, the proposed experiments will make use of liquid helium, whose high purity and ability to be precisely and accurately controlled over a wide range of parameters make in uniquely suited for quantitatively testing current fluid dynamics theories. Drops will be made to collide with the bulk liquid interface, and the rapidly changing stress field occurring at the interface rupture will radiate sound waves which will be detected with a temporal resolution of 10 ns, approaching rupture time scales at the molecular level. The research program will provide unique training opportunities for graduate students in methods of acoustics, an area often overlooked in contemporary physics, and involving special, often-subtle experimental methods. This is a fundamental project but the results are potentially relevant to a range of practical situations including industrial processes involving foams and emulsions, in commercial blenders and sprayers, application of ultrasound in medicine, generation of underwater noise by rain, which is important in military and environmental monitoring, etc. ***