US-Japan Cooperative Research: Vortex Dynamics and Organized Structures in Turbulent Shear Flows

该奖项将支持休斯顿大学Fazle Hussain教授及其同事和日本北海道大学Masaru Kiya教授以及其他日本研究人员共同开展的一项名为“湍流剪切流中的涡旋动力学和有组织结构”的联合合作研究项目。研究人员指出，流体湍流是科学家和工程师面临的最有趣但最难理解的物理现象之一。流体运动控制方程固有的非线性和由此产生的（明显的）随机湍流是造成这一困难的主要原因。湍流剪切流具有相干结构的特征，但关于这些结构的详细拓扑特征及其动力学行为的知识很少。为了深入了解这一领域，研究人员将研究几种剪切流，如射流、尾迹、混合层和泰勒-库埃特流。相干结构拓扑和动力学将在这些流动中使用两种计算机测量技术进行实验研究。然后将开发和分析模型，以预测湍流剪切流中相干结构的混沌演化。这项研究可能会导致对湍流管理（操纵技术上重要的现象，如热、质量和动量的传输；夹带；混合和化学反应，包括燃烧；以及阻力和气动噪声的产生）的进一步理解。美国和日本的首席研究员都是备受尊敬的工程师。每个人都在各自的领域作出了重大贡献。该奖项将扩大和维持他们富有成效的合作，这将证明有利于整个湍流社区。

This award will support a joint cooperative research project entitled "Vortex Dynamics and Organized Structures in Turbulent Shear Flows" between Professor Fazle Hussain and colleagues at the University of Houston and Professor Masaru Kiya of Hokkaido University in Japan and other Japanese investigators. The researchers note that fluid turbulence is one of the most intriguing yet difficult-to-understand physical phenomena facing scientists and engineers. The inherent nonlinearity of the governing equations of fluid motion and the resulting (apparently) random turbulence are largely responsible for this difficulty. Turbulent shear flows are characterized by coherent structures, but knowledge about the detailed topological characteristics of these structures and their dynamical behavior is scarce. To provide insight into this area the researchers will study several shear flows such as jets, wakes, mixing layers, and Taylor-Couette flows. Coherent structure topology and dynamics will be studied experimentaly in these flows using two computerized measuring techniques. Models will then be developed and analyzed to predict chaotic evolutions of coherent structures in turbulent shear flows. This research could lead to a further understanding of turbulence management (manipulation of technologically important phenomena such as transports of heat, mass, and momentum; entrainment; mixing and chemical reaction, including combustion; and generation of drag and aerodynamic noise). Both the U.S. and Japanese principal investigators are highly respected engineers. Each has established a record of significant contributions in his respective area. This award will expand and sustain their productive cooperation, which should prove beneficial to the entire turbulent flow community.