基于嵌入空间变形体法的流固耦合网格更新

Mesh update method for fluid-solid coupling computation based on embedding spatial deformation method

为解决在传统基于松耦合技术的流固耦合计算中由于单元类型和数量的不同,网格变形不协调、计算收敛困难以及计算误差大等问题,在进行流固耦合网格更新计算中引入了计算机图形学中基于自由变形(FFD)原理的嵌入空间变形体方法,通过将少量结构节点作为控制点来完成大量流体网格的高阶连续变形功能.计算中考虑了湍流来流边界条件的影响,与采用分区插值方法的计算结果进行了比较,并对流固耦合中的气动阻尼特性进行了分析.验证算例表明:该方法实现了高层建筑的任意复杂连续侧弯及扭转变形,且不受建筑外形复杂程度的影响;计算收敛性和精度更高,数值计算结果与风洞试验的结果吻合更好.

A mesh update scheme on the basis of computer graphics principle of free-form deformation（FFD） was introduced for loosely fluid-solid coupling to address issues such as the difference of element type and amount,the mesh deformation without coordination,the convergence difficulties and the calculation errors.The higher order and continuous deformation of fluid mesh was implemented by embedding spatial deformation method based on FFD.The deformation of fluid meshes was controlled by structure grids which usually have fewer number than the outer mold surface defined by the fluid mesh.The effect of turbulent flow boundary conditions was taken into account.Comparison was carried out with FFD method and the partitioned interpolation method.The aerodynamic damping characteristics were also analyzed.It is found that FFD method implements the high-rise building＇s arbitrarily complex continuous lateral bending and torsion,and the problem of the complicated architectural shape can also be solved with good convergence and high precision.The numerical results acquired by the study well accorded with those of wind tunnel test.