Studies of Rotating Fluids

摘要哈特，约翰E. 科罗拉多大学ATM-9714221题目：旋转流体研究 本研究的目的是通过对机械驱动旋转流体的实验室实验，对与大气动力学相关的理论和建模技术进行严格的检查。将使用高分辨率粒子图像测速仪和激光多普勒测速仪对单层和双层系统中的速度场进行详细测量。 这些数据将检验斜压波混沌理论、湍流的雷诺应力闭合模型和目前用于气象大涡模拟的亚网格尺度模拟方法。大多数实验将在旋转圆柱体中进行，流体运动由差动旋转盖机械驱动。该系统具有简单、方向均匀、能够研究大范围的雷诺数（103 ~ 106阶）、适合于使用粒子图像测速技术以及比较模型预测与实验数据相对容易等优点。 两层流动的实验将集中在斜压不稳定性和混沌问题的不对称性。 一组广泛的单层流动实验将提供侧壁上不稳定性的分类，以及顶部和底部边界层中分离和不稳定性的数据。初步工作表明，这三个参数的系统有许多不稳定性，混合在垂直爆发的水平边界层。 这些现象对于理解大气涡旋下边界层的行为是很重要的。 流动的详细特性将与轴对称数值模拟和线性不稳定理论的结果进行比较。 诸如此类的基础研究是未来改进大气运动数值模式的基础。

Abstract Hart, John E. University of Colorado ATM-9714221 Title: Studies of Rotating Fluids The objective of this research is a critical examination of theories and modeling techniques relevant to atmospheric dynamics, by means of laboratory experiments on mechanically driven rotating fluids. Detailed measurements of velocity fields in single-layer and two-layer systems will be made using high resolution particle image velocimetry and laser doppler anemometry. The data will test theories of baroclinic wave chaos, Reynolds stress closure models of turbulence, and subgrid scale modeling methods currently used in meteorological large eddy simulations. Most of the experiments will take place in a rotating cylinder, with fluid motions being driven mechanically by a differentially rotating lid. This system has advantages of simplicity, the presence of a homogeneous direction, the ability to study a large range of Reynolds numbers (l03 to order 106), the suitability for use of particle image velocimetry, and the relative ease of comparing model predictions with the experimentaldata. Experiments on two-layer flows will focus on asymmetries in the baroclinic instability and chaos problems. An extensive set of experiments on single-layer flows will provide a categorization of instabilities on the sidewall, as well as data on separation and instability in the top and bottom boundary layers. Preliminary work has shown that this three-parameter system has numerous instabilities, mixed in with vertically erupting horizontal boundary layers. These phenomena are important for understanding the behavior of boundary layers under atmospheric vortices. Detailed characteristics of the flows will be compared with results from axisymmetric numerical simulations and linear instability theory. Fundamental studies such as these underlie future improvements in numerical models of atmospheric motions.