Presidential Young Investigators Award: Simulation of Complex Reacting Flows

基于谱元算法，结合伪谱方法的准确性和有限元技术的通用性，构建了模拟三维非定常湍流反应流的计算机代码。采用大涡模拟技术，对亚网格湍流运动进行近似模拟，而对大尺度结构进行直接计算。标量子网格闭合采用单点概率密度函数法，流体动力闭合采用双方程子网格模型。在第二个程序中，可压缩性对超高速三维反应湍流的影响将使用混合有限差分/单元伪谱算法进行研究。最近开发的几种激波捕获方案将用于高马赫数流动模拟。深入了解湍流反应流对于在高效率和低排放的约束下运行现代发动机和动力系统至关重要，而下一代超音速飞机提出的问题可能无法通过传统的实验和开发技术来回答。这个研究项目将为工程师们提供新的工具，以获取这些问题的答案。

A computer code is to be constructed to simulate three- dimensional unsteady turbulent reactive flows, based upon a spectral element algorithm which combines the accuracy of pseudospectral methods with the versatility of finite-element techniques. The large eddy simulation technique will be used, in which the subgrid turbulent motion is modeled approximately while the large scale structures are calculated directly. A single-point probability density function method will be developed for the scalar subgrid closure, and a two-equation subgrid model will be employed for the hydrodynamic closure. In a second program, the effects of compressibility on hyper- velocity three-dimensional reacting turbulent flows will be investigated using a hybrid finite difference/element pseudospectral algorithm. Several recently developed shock capturing schemes will be implemented for high Mach number flow simulations. The thorough understanding of turbulent reactive flows is essential to operate modern engines and power systems within the constraints of high efficiency and low emissions, and the next generation of supersonic aircraft poses questions which may not be answerable through traditional experimentation and development techniques. This research program will provide new tools for engineers to extract answers to many of those questions.