Development and Implementation of Practical Optimal LES Models

摘要提案编号： CTS-0352552主要制造商：Robert D.研究机构： 在许多技术设备中，预测和/或控制湍流流体流动的影响是非常重要的，因为湍流的行为可能最终控制设备的性能。 大涡模拟（LES）是可靠地预测高雷诺数湍流流动的最有前途的技术之一。 在大涡模拟中，湍流的最大尺度被模拟，而最小尺度的影响被建模。 然而，有一些挑战要克服LES实现其全部潜力;这些包括近壁湍流的处理和数值离散化的影响，特别是在具有复杂几何形状的流动中。拟议的研究的目标是产生LES模型，将提供可靠的预测在广泛的湍流。该方法是应用“最优LES”配方，其中LES模型是通过一个正式的优化过程。 最佳LES模型制定的小分离多点速度相关性。 开发此类模型的主要挑战是获得所需的速度相关性，而无需诉诸广泛的经验数据。 所需的统计相关性将使用动态技术开发，其中相关性是从运行模拟和理论考虑中估计的。 在目前的项目中，特别感兴趣的是模拟近壁湍流、标量输运和压缩性。 这一发展的结果将是一个广泛适用的和准确的LES建模技术，这将在应用CFD代码中实现。 优化LES将发展成为一个强大的预测工具，在广泛的湍流流动。 这将对许多以湍流为主要现象之一的工程应用产生重大影响。 重要的例子是：气体涡轮机发动机中的流动，多元件高升力翼型上的流动，以及搅拌槽反应器中的流动。有了可靠的LES模拟，这些和许多其他应用将享受改进的新设计，并降低设计成本所产生的测试需求减少。

ABSTRACTPROPOSAL NO.: CTS-0352552PRINCIPAL INVESTIGATOR: ROBERT D. MOSERINSTITUTION: UNIVERSITY OF ILLINOIS, URBANA-CHAMPAIGNDEVELOPMENT AND IMPLEMENTATION OF PRACTICAL OPTIMAL LES MODELS In many technological devices, it is of great importance to predict and/or control the effects of turbulent fluid flows, because the behavior of the turbulence may ultimately control the performance of the device. Large eddy simulation (LES) is one of the most promising techniques for reliable prediction of the high Reynolds number turbulent flows of technological interest. In LES, the largest scales of turbulence are simulated while the effects of the smallest scales are modeled. However, there are a number of challenges to overcome for LES to realize its full potential; these include the treatment of near-wall turbulence and the impact of numerical discretization, especially in flows with complex geometries. The objective of the proposed research is to produce LES models that will provide reliable predictions in a broad range of turbulent flows. The approach is to apply the "Optimal LES" formulation, in which LES models are developed through a formal optimization process. Optimal LES models are formulated in terms of small separation multi-point velocity correlations. The primary remaining challenge in developing such models is obtaining the required velocity correlations, without resorting to extensive empirical data. The required statistical correlations will be developed using dynamic techniques, in which the correlations are estimated from the running simulation and from theoretical considerations. Of particular interest in the current project will be modeling near-wall turbulence, scalar transport and compressibility. The results of this development will be a broadly applicable and accurate LES modeling technique, which will be implemented in application CFD codes. Optimal LES will be developed into a powerful predictive tool in a wide range of turbulent flows. This will have great impact on many engineering applications in which turbulence is one of the dominant phenomena. Important examples are: flow in gas turbine engines, flow over multi-element high-lift airfoils, and flow in stirred tank reactors. With reliable LES simulations, these and many other applications will enjoy improved new designs, and reduced design costs arising from the decreased need for testing.