基于γ-Re_(θt)转捩模型的高雷诺数旋转圆柱绕流数值研究  

Numerical study on the flow around a rotating cylinder with high Reynolds number based on γ-Re_(θt) model

作　　者：徐一航 陈少松[1] XU Yihang;CHEN Shaosong(School of Energy and Power Engineering,Nanjing University of Science and Technology,210094 Nanjing,China)

机构地区：[1]南京理工大学能源与动力工程学院,南京210094

出　　处：《应用力学学报》2024年第5期1193-1203,共11页Chinese Journal of Applied Mechanics

摘　　要：采用γ-Re_(θt)转捩模型对高雷诺数下旋转圆柱绕流的壁面边界层的流动特征以及边界层的转捩现象进行数值模拟,用Re=5.0×10^(3)时的旋转圆柱绕流问题作为算例与直接数值模拟(direct numerical simulation,DNS)的结果进行了对比,验证了γ-Re_(θt)转捩模型在模拟旋转圆柱绕流问题方面的准确性。然后分别对亚临界区、临界区和超临界区的旋转圆柱绕流问题进行数值模拟,分析了不同雷诺数和不同相对转速下旋转圆柱绕流的近壁面流动特征及表面时均压力系数、时均摩擦力系数,总结了圆柱表面绕流转捩位置相对转速的变化规律。结果表明,当自由来流雷诺数一定时,圆柱下表面来流与线速度方向一致处的转捩点随相对转速的增加而后移,圆柱上表面来流与线速度方向相反处的转捩点随相对转速的增加而前移。圆柱上表面来流与线速度方向相反处的流动分离是由于壁面黏性摩擦和逆压梯度共同作用下导致动能下降的结果,并且壁面的运动方向与主流方向相反更加剧了黏性摩擦对动能的耗散。圆柱下表面来流与线速度方向一致处的流动分离是由于背风面的逆压梯度致使壁面附近流体无法继续跟随壁面运动而产生回流的结果。The characteristics of flow field around a rotating cylinder were first investigated by the γ-Re_(θt) model at Re=5.0×10^(3).The simulation results were compared with DNS which verified the advantage of γ-Re_(θt) model in simulating the flow around rotating cylinder.The simulation was carried out in subcritical,critical and supercritical regions.The rotating cylinder flow field characteristics of boundary layer and time-averaged pressure coefficient,friction coefficient were demonstrated in the different Re and relative rotating speed,which summarized the change law of transition point with relative rotating speed in the upper and lower surfaces.Results showed that the transition point on the lower surface moves backward with the increase of relative speed when the Re of free stream is constant,and it moves forward on the upper surface,conversely.The flow separation on the upper surface was caused by the decrease of kinetic energy due to the combined action of wall viscous friction and adverse pressure gradient.Meanwhile,the motion direction of the wall was opposite to the main flow direction,which made the dissipation of kinetic energy by the viscous friction more intense.The flow separation on the lower surface was the result of the backflow caused by pressure gradient on the leeward side,which made near-wall fluid unable to follow the wall.

关 键 词：旋转圆柱绕流 γ-Re_(θt)转捩模型 转捩现象 流动分离 

分 类 号：O357.5[理学—流体力学] V211.3[理学—力学]