摘要
目的研究浸入边界算法在传统CFD领域中的应用,改善内部流场处理方法及壁面处理措施.方法采用适用于刚性边界的浸入边界算法(Virtual Boundary Method),结合时间分步法和交错网格编写出流场计算程序,开展算法模型细节分析及不同雷诺数下二维方柱绕流的数值模拟.结果仅采用双线性插值而忽略内部流场拟化出的物体边界速度收敛至10-7.反馈系数形成的边界能够隔绝内外流场,并使内部流体处于衰减状态;不同雷诺数时方柱绕流流场结构同其他文献相同,不同工况所得气动力参数变化规律均能较好地吻合同类文献数据;壁面处理措施使气动力计算误差降低至10-3.结论 3种工况所得数据均能较好地吻合过往文献所得气动力系数变化规律,在均匀网格下采用壁面处理后的气动力系数虽然更接近于其他参考数据,但不能成为其能够修正壁面流动参数使其得到合理分布的充分依据.均匀网格所造成的近壁面流动特征捕捉缺失亦可能是造成数据差异的原因,且反映此问题的数据差异变化规律亦能在其他文献得到体现,进一步从数值精度方面验证了浸入边界算法程序的模拟能力.
To improve the treatment for inner and boundary flow field, the application of the im- mersed boundary algorithm in traditional CFD territory was studied in this paper. Using the virtual boundary method that is suitable to rigid boundaries and the fractional time-step method, a comput- er procedure was developed to numerically simulate a flow around square cylinder with differentReynolds numbers. Results show that the body shape can be successfully built by bilinear interpola- tion with neglecting inner flow field and the values of U-boundary can be converged to 10 ^-7. The inner and outer flow fields are isolated with the boundary that is constructed by feedback parame- ters, which causes the inner flow field to be in a attenuation state. The obtained aerodynamic force coefficients for three different cases have good agreement with the results of other literatures and the calculation error is reduced to 10^-3. Although the aerodynamics coefficients calculated with equidistant grids for boundary treatment can also be closed to the results of the known references, it is not necessary to conclude that this boundary treatment can get a reasonable fluid parameter distribution. The shortage of catching flow characteristic near the border caused by equidistant girds may be the reason for producing errors. Some similar phenomena are also reported in other literatures. It indicates that the proposed immersed boundary algorithm has good numerical accuracy.
出处
《沈阳建筑大学学报（自然科学版）》
CAS
北大核心
2014年第5期778-785,共8页
Journal of Shenyang Jianzhu University：Natural Science
基金
国家重点基础研究973计划项目(2013CB036301)
土木工程防灾国家重点实验室自主研究课题基金项目(SLDRCE09-B-04)
高校博士点基金项目(20100072110051)
关键词
浸入边界算法
内部流场
壁面处理
双线性插值
反馈系数
immersed boundary algorithm
inner flow field
boundary treatment
bilinear interpolation
feedback parameter
