Numerical Investigation of Aero-elasticity in Modern Low-Pressure Turbines

现代航空低压涡轮机（LPT）的一个特点是叶片负荷高，具有复杂的瞬态和分离流态。这种气动非定常流场可能以复杂的非线性方式与叶片的结构运动相互作用，导致颤振和强迫响应不稳定。为了检查振动应力水平并确保叶片的机械完整性，了解未来几代LPT颤振发生的物理过程至关重要。本研究采用一种新的方法来探讨现代LPT的颤振和强迫响应机理。采用直接数值模拟模型作为计算风洞，研究各种不稳定源对叶片力响应和颤振不稳定性的影响。数值模型也将被用来确定相对的优点和适当的工作范围，目前的低保真数值方法，为现代LPT航空力学设计和分析。

A feature of modern aeronautical Low Pressure Turbines (LPTs) is their high blade loadings with complex transient and separated flow regimes. This aerodynamic unsteady flow field may interact with blade's structure motion in a complex non-linear fashion leading to flutter and forced response instability. Understanding the physics of onset of flutter for future generations of LPTs is essential in order to examine the vibration stress levels and ensuring blade mechanical integrity. In this project, a novel method is used to explore the mechanism of flutter and forced response in modern LPTs. Using a direct numerical simulation model as a computational wind tunnel, the effects of various sources of unsteadiness on force response and flutter instability of blades will be studied. The numerical model will also be used to identify the relative merits and adequate working range of current low-fidelity numerical methods for modern LPT aeromechanical design and analysis.