Bluff-Body Transient Wind Effects via CFD

9705648 Scanlan根据气动弹性理论，物体或物体在风中的运动伴随着由横流引起的随时间变化的气动升力。 这种提升滞后于身体运动，在其“建立”中表现出时间延迟。 这些特性以伴随着机体迎角单位阶跃变化的指数升力函数为代表。 本项目将通过计算流体动力学（CFD）的新应用研究各种桥面形状的这些指标函数的特征，该计算流体动力学（CFD）在采用既定计算代码的同时，以新的方式应用它，以避免与以下全周期身体振荡相关的相当大的复杂性。 特别的应用-在强风下桥面的稳定性-在大跨度桥梁的设计研究中是直接有用的。 该研究提供了完全避免与桥梁稳定性相关的某些风洞实验的前景，从而使设计周期更有效，特别是对于大跨度桥梁。 ***

9705648 Scanlan By theory of aeroelesticity, motion of a body or object in wind is accompanied by time-varying aerodynamic lift occasioned by the crossflow. This lift lags behind the body motion, exhibiting a time delay in its "build-up". Such characteristics are typified by indicial lift functions that accompany a unit step change in angle of attack of the body. This project will study the character of such indicial functions for various bridge deck shapes through a novel application of Computational Fluid Dynamics (CFD) which, while employing an established computational code, applies it in a new way that avoids the considerable complications associated with following full-cycle body oscillation. The particular application - the stability of bridge decks under high winds- is of direct usefulness in design studies for long- span bridges. The research offers the prospect of entirely avoiding certain wind tunnel experiments related to bridge stability, thus making the design cycle more efficient, particularly for long-span bridges. ***