Mechanisms and Active Control of Jet-Induced Noise

本子项目旨在为飞机发动机喷气机的剪切（或混合）层产生的噪声提供参考数据。采用精细、高阶精确的直接数值和大涡模拟（DNS/LES）对剪切层流场的不稳定性、动态大尺度结构、湍流和噪声产生进行了模拟。这些数据将用于进行远场噪声预测的调查，并通过其他子项目验证近场和中场的声音传播方法和方案。然而，最终的目标是研究声音的产生机制及其可能的控制。为此，模拟结果将提供给IMFT（图卢兹）的法国合作伙伴，在那里它们将作为解决噪声识别伴随问题的初始条件：这将使人们能够深入了解噪声产生的基本机制。最后，将采用最优控制理论找到最合适的降低噪声的方法，使执行器尽可能靠近噪声源。

This sub-project aims at providing reference data for the noise produced by the shear (or mixing) layers of an aircraft-engine jet. Careful, high-order accurate direct numerical and large-eddy simulations (DNS/LES) are used to simulate the shear-layer flow-field with its instabilities, dynamical large-scale structures, turbulence, and noise generation. The data will be used for performing investigations on far-field noise prediction, with validation of sound propagation methodologies and schemes in the near- and in the medium field by the other sub-projects. The ultimate aim however consists of investigations of the sound generation mechanisms and their possible control. To this end simulation results will be given to the French partner at IMFT (Toulouse) where they will serve as initial Kondition for solving an adjoint problem for noise identification: this will allow insight into the fundamental mechanisms of noise generation. Finally, optimal control theory will be employed to find the most appropriate means for reducing noise, with actuators situated as close as possible to the noise source.