摘要
为提高大涡数值模拟(large eddy simulation,LES)中生成格栅湍流风场效率,对一种LES湍流生成方法进行改进,在入口边界处设置虚拟格栅网获取网状射流,并将其成功应用于Re=3900的圆柱绕流模拟.结果表明:基于虚拟格栅生成的湍流风场具有各向同性特征,各湍流强度沿流向呈指数衰减趋势,湍流积分尺度沿流向呈线性增长趋势,且脉动风速功率谱与von Kármán谱吻合较好.此外,相较于均匀来流,湍流来流下圆柱的平均阻力系数减小,而阻力系数和升力系数的标准差均大幅增加,即湍流会加剧圆柱升阻力的脉动效应.来流湍流对圆柱表面的流动分离有抑制作用,可使分离点位置后移,导致回流长度和斯脱罗哈数减小,同时使尾流涡旋脱落不稳定、涡脱能量更强.
To further improve the efficiency of grid-generated turbulent wind field for large eddy simulation(LES),an improved turbulence generation method based on LES is proposed in this paper,in which grid-jet can be obtained on the inlet boundary.Then,LES of the flow around a circular cylinder at Re=3900 is successfully carried out.The results indicate that the turbulent wind field generated based on virtual grid exhibits isotropic characteristics.The turbulence intensity decreases exponentially along the flow direction,and the turbulence integral scale increases linearly along the flow direction.The fluctuating wind power spectrum is consistent with the von Kármán spectrum.In addition,compared to a smooth inflow,the mean drag coefficient of the cylinder decreases in the turbulent inflow,whereas the standard deviation of the drag coefficients and lift coefficients increase significantly,indicating stronger pulsations of the lift and drag forces in turbulent flow.Turbulence also delays flow separation on the cylinder surface and inhibits separation,resulting in a shorter recirculation length and a lower Strouhal number.Vortex shedding becomes unstable and the shedding energy is stronger.
作者
靖洪淼
赵志恒
李维康
张胤璇
乔明哲
杨雄伟
JING Hongmiao;ZHAO Zhiheng;LI Weikang;ZHANG Yinxuan;QIAO Mingzhe;YANG Xiongwei(School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;Key Laboratory of Road and Railway Engineering Safety and Security,Ministry of Education,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;Department of Railway Engineering,Shijiazhuang Institute of Railway Technology,Shijiazhuang 050041,China;School of Urban Geology and Engineering,Hebei GEO University,Shijiazhuang 050031,China)
出处
《湖南大学学报(自然科学版)》
北大核心
2025年第11期214-226,共13页
Journal of Hunan University:Natural Sciences
基金
国家自然科学基金资助项目(52208494)
河北省自然科学基金资助项目(E2024210037,E2021210063)
河北省自然科学基金创新研究群体项目(E2022210078)
河北省高端人才项目([2019]63号)。
关键词
虚拟格栅
湍流
圆柱绕流
大涡模拟
流场
virtual grid
turbulence
flow around a circular cylinder
large eddy simulation
flow field
