不同倒角半径四柱体绕流数值模拟及水动力特性分析

为研究四柱体布置情况下倒角半径变化对柱体绕流水动力特性的影响,使用Fluent软件,采用大涡模拟方法研究了在雷诺数Re=3 900下6种不同倒角半径的柱体在方形四柱体布置时的三维流场。在模型分析验证有效后,分析了柱体后方瞬时流场、水动力参数、时均流场的变化情况。分析结果表明:随着倒角半径的增大,上游柱体的平均阻力系数逐渐减小,下游柱体的平均阻力系数除了在R~+=0.1处增幅很大以外,其余均随倒角半径变大而平稳变大;各柱体的升力系数均方根变化趋势基本相同;R~+=0.1、0.5时,上下游两柱体的升力系数曲线相位相反,而在R~+=0.2、0.3和0.4时,上下游两柱体的升力系数曲线相位相同。

Numerical simulation and hydrodynamic characteristics analysis of flow past a cylinder with different rounded radiuses under four square-arranged cylinders

In order to study the influence of the change of rounded radius on the dynamic characteristics of the flow around four square-arranged cylinders, by using Fluent software and the method of large eddy, we simulated the three-dimensional flow around cylinder with 6 different rounded radiuses under the Reynolds number of 3 900. After the effective verifition of the model, the changes of the instantaneous flow field, the hydrodynamic parameters and the time averaged flow field were obtained and analyzed. The results show that with the increase of the rounded radius, the average drag coefficient of the upstream cylinder gradually decreases, and the average drag coefficient of the downstream cylinder increases with the increase of the chamber radius except for the sudden increase at R⁺=0.1. The root mean square trend of the lift coefficient of each cylinder is basically the same. When R⁺=0.1 and 0.5, the lift coefficient curves of the upper and lower two cylinders are opposite in phase, while at R⁺=0.2, 0.3 and 0.4, the lift coefficient curves of the upper and lower two cylinders are in the same phase. Comparing R⁺=0.1, it is found that vortex shedding is the main factor affecting the lateral flow velocity fluctuation.