Presidential Young Investigators Award: Simulation of Complex Reacting Flows

基于一种结合了拟谱方法的精度和有限元技术的通用性的谱元素算法，将构造一个计算机代码来模拟三维非定常湍流反应流。采用大涡模拟技术，对亚网格湍流运动进行近似模拟，直接对大尺度结构物进行计算。采用单点概率密度函数方法对标量子网格进行闭合，对水动力闭合采用两方程子网格模型。在第二个程序中，将使用有限差分/单元伪谱混合算法来研究可压缩性对超高速三维反应湍流流动的影响。最近开发的几种激波捕获方案将被用于高马赫数流动模拟。对湍流反应流动的透彻了解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是至关重要的，而下一代超音速飞机提出了一些传统的实验和开发技术可能无法回答的问题。这一研究计划将为工程师提供新的工具，以提取其中许多问题的答案。

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.