Investigation of Cloud Entrainment Using a Laboratory Heated-Jet Analogue

使用实验室加热喷射模拟研究云夹带

• 批准号: 9714810
• 负责人: Ajay Prasad
• 金额: $ 15.76万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-02-15 至 2001-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9714810&HistoricalAwards=false
• 关键词: Investigation; Cloud; Entrainment; Using; Laboratory

Abstract/Prasad, 9714810 It is difficult to make good observations in real clouds. At best, using aircraft, balloons, and radar, researchers have been able to get a few "snapshots" of what is going on in a limited region of a aq few clouds at particular instants, but to do so is very costly and difficult. Thus our knowledge of cloud processes is very spotty and limited. The difficulty of getting good observations of real clouds has led a number of investigators to try to get at an understanding of cloud processes by studying analogs of cloud processes in laboratory simulations using liquids. Although there are some problems inherent in this approach because of differences between liquids and air (liquids are generally virtually incompressible, for example), there are still many questions that may be addressed usefully in this way. One of these is the question of entrainment of environmental dry air into clouds. This award supports research using a laboratory analog of a buoyant developing cloud to address the problem of entrainment. The release of latent heat in a cloud by condensation will be simulated by injecting heat ohmically, that is, through heated wires in the fluid flow. The flow fields will be visualized using some of the most recent advanced techniques, including Laser Induced Fluorescence, Particle Image Velocimetry, and Particle Image Thermometry. The planned research is expected to provide new and fresh insights about entrainment, and to lead to improvements in the characterization of buoyant convection and entrainment in numerical models of clouds.

摘要/普拉萨德，9714810在真实的云层中很难进行良好的观测。充其量，使用飞机、气球和雷达，研究人员已经能够在特定时刻获得在少数云的有限区域内正在发生的事情的几个“快照”，但这样做是非常昂贵和困难的。因此，我们对云过程的了解非常参差不齐，而且非常有限。很难对真实的云进行良好的观测，这使得许多研究人员试图通过在实验室使用液体模拟云过程来研究云过程的模拟，以了解云过程。尽管由于液体和空气之间的差异，这种方法存在一些固有的问题(例如，液体通常实际上是不可压缩的)，但仍然有许多问题可以通过这种方式有效地解决。其中之一是环境干燥空气进入云层的问题。该奖项支持使用浮力发展云的实验室模拟来解决卷吸问题的研究。通过欧姆注入热量，即通过流体流动中的加热导线，可以模拟云中凝结释放潜热的过程。流场的可视化将使用一些最新的先进技术，包括激光诱导荧光、粒子图像测速和粒子图像测温。计划中的研究有望提供关于卷吸的新的和新的见解，并导致在浮力对流和云的数值模型中的卷吸的特征方面的改进。