Bluff-Body Flutter Derivatives via CFD

目前的项目围绕着一个被称为“颤振导数”的中心概念，这是在某些空气动力学背景下需要确定的量。例如，对于放置在横风流中的物体，这种导数就会出现，其中空气动力升力、阻力或力矩的无量纲形式由系数C给出，该系数C根据物体的倾斜角而变化。颤振导数C′被证明在钝型结构（如长桥）对风的响应中是至关重要的，因为它们的特性清楚地定义了桥梁在风中变得不稳定的可能倾向。针对桥梁的工程设计，迄今为止仅通过风洞试验获得桥面形式的系数C′。然而，现在随着计算流体力学的进步，仅通过计算就有可能获得C'的知识。这类研究还处于研究和开发阶段，需要在计算和风洞实验之间进行来回交流。//

The present project hinges around a central concept known as "flutter derivatives" which are quantities that need to be identified in certain aerodynamic contexts. Such derivatives arise, for example, in regard to a body placed in a cross-wind flow, where the dimensionless form of the aerodynamic lift, drag or moment is given by a coefficient C that changes according to the angle of inclination of the body. The flutter derivatives C' prove to be of key importance in the response of bluff structures- like long bridges- to wind, as their characteristics clearly define the possible proclivity of the bridge to become unstable in the wind. Focusing on the engineering design of bridges, knowledge of the coefficients C' for bridge deck forms has heretofore been acquired exclusively by means of wind tunney experiment. Now, however, with advances in computational fluid dynamics, the possibility arises of acquiring knowledge of C' via calculation alone. such studies lie in the realm of research and development, and a back-and-forth exchange between calculation and wind tunney experiment is needed.//