基于FFD变换的高层建筑风致流固耦合数值模拟研究

Numerical simulation of wind-induced fluid-structure interactions for high-rise buildings based on FFD transform

在采用松耦合方法进行建筑物的风致流固耦合计算时,由于结构模型的节点数量通常要比流体计算模型的节点少,因此变形的连续性和协调性往往会由于所采用算法的不当而失真,继而导致计算收敛困难和结果误差。提出一种基于自由变形(Free-Form Deformation,FFD)原理的高层建筑三维变形方法,即在不改变建筑表面流体网格数量和拓扑关系的前提下,通过将结构节点作为建筑物变形的控制点,实现利用少量结构节点变形信息完成大量流体网格的高阶连续变形的功能。通过算例验证以及与风洞试验结果和已有文献成果的比较表明,本文方法实现高层建筑的任意复杂连续侧弯及扭转变形,数值模拟结果与试验吻合得更好,提高数值计算的精度,增强计算的收敛性。

In most cases of wind-induced aeroelastic analysis of high-rise buildings using a loosely coupled method, convergence difficulties and errors often occur due to the distortion of the continuity and coordination of deformation of the simple structural finite element models which usually have fewer nodal points than the outer mold surface defined by the fluid mesh. The deformation method of high-rise buildings is presented based on the free form deformation principle. Under the premise without changing the number and topology of the grid on the building surface, the high order continuous deformation of the large amount of fluid mesh using the information of a small amount of structural mesh deformation are achieved, by taking the structural nodal points as the control points. The validity and effectiveness of this method, which may model continuous curvature and complex torsion of high-rise buildings, are confirmed through an example and comparing with results from wind tunnel test and other published papers.