Bluff-Body Transient Wind Effects via CFD

9705648斯堪兰根据空气弹性理论，物体或物体在风中的运动伴随着由横流引起的时变气动升力。这个升力落后于身体的运动，在它的“建立”方面表现出时间上的延迟。这种特征的典型特征是伴随着机身攻角单位阶跃变化的指示性升力函数。本项目将通过计算流体动力学(CFD)的一种新应用来研究不同桥面形状的这些指标函数的特征。CFD在使用已建立的计算程序的同时，以一种新的方式应用它，从而避免了随之而来的全周期车身振动带来的相当大的复杂性。这种特殊的应用--大风下桥面的稳定性--在大跨度桥梁的设计研究中直接有用。这项研究提供了完全避免某些与桥梁稳定性相关的风洞试验的前景，从而使设计周期更有效率，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. ***