The paper examines the dynamic stall characteristics of a finite wing with an aspect ratio of eight in order to explore the 3D effects on flow topology,aerodynamic characteristics,and pitching damping.Firstly,CFD meth...The paper examines the dynamic stall characteristics of a finite wing with an aspect ratio of eight in order to explore the 3D effects on flow topology,aerodynamic characteristics,and pitching damping.Firstly,CFD methods are developed to calculate the aerodynamic characteristics of wings.The URANS equations are solved using a finite volume method,and the two-equation k-ωshear stress transport(SST)turbulence model is employed to account for viscosity effects.Secondly,the CFD methods are used to simulate the aerodynamic characteristics of both a static,rectangular wing and a pitching,tapered wing to verify their effectiveness and accuracy.The numerical results show good agreement with experimental data.Subsequently,the static and dynamic characteristics of the finite wing are computed and discussed.The results reveal significant 3D flow structures during both static and dynamic stalls,including wing tip vortices,arch vortices,Ω-type vortices,and ring vortices.These phenomena lead to differences in the aerodynamic characteristics of the finite wing compared with a 2D airfoil.Specifically,the finite wing has a smaller lift slope during attached-flow stages,higher stall angles,and more gradual stall behavior.Flow separation initially occurs in the middle spanwise section and gradually spreads to both ends.Regarding aerodynamic damping,the inboard sections mainly generate unstable loading.Furthermore,sections experiencing light stall have a higher tendency to produce negative damping compared with sections experiencing deep dynamic stall.展开更多
泰州自2015年6月24日起宣布入梅以来降水不断,其中伴随着多次暴雨到大暴雨过程。该文利用micaps常规观测资料、卫星云图等资料,对6月27日在泰州中南部出现的大暴雨进行分析,通过对大尺度环流场、物理量场和中尺度系统的分析,得出本次暴...泰州自2015年6月24日起宣布入梅以来降水不断,其中伴随着多次暴雨到大暴雨过程。该文利用micaps常规观测资料、卫星云图等资料,对6月27日在泰州中南部出现的大暴雨进行分析,通过对大尺度环流场、物理量场和中尺度系统的分析,得出本次暴雨是在典型的梅雨期三阻形的形势下[1],受850 h Pa和700 h Pa切变线和地面倒槽的共同影响造成的,水汽条件和热力条件都有利于暴雨的发生和持续,地面中小尺度辐合系统是这次暴雨的触发机制。展开更多
基金supported by the National Natural Science Foundation of China(No.12072156)the National Key Laboratory Foundation of China(No.61422202103)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘The paper examines the dynamic stall characteristics of a finite wing with an aspect ratio of eight in order to explore the 3D effects on flow topology,aerodynamic characteristics,and pitching damping.Firstly,CFD methods are developed to calculate the aerodynamic characteristics of wings.The URANS equations are solved using a finite volume method,and the two-equation k-ωshear stress transport(SST)turbulence model is employed to account for viscosity effects.Secondly,the CFD methods are used to simulate the aerodynamic characteristics of both a static,rectangular wing and a pitching,tapered wing to verify their effectiveness and accuracy.The numerical results show good agreement with experimental data.Subsequently,the static and dynamic characteristics of the finite wing are computed and discussed.The results reveal significant 3D flow structures during both static and dynamic stalls,including wing tip vortices,arch vortices,Ω-type vortices,and ring vortices.These phenomena lead to differences in the aerodynamic characteristics of the finite wing compared with a 2D airfoil.Specifically,the finite wing has a smaller lift slope during attached-flow stages,higher stall angles,and more gradual stall behavior.Flow separation initially occurs in the middle spanwise section and gradually spreads to both ends.Regarding aerodynamic damping,the inboard sections mainly generate unstable loading.Furthermore,sections experiencing light stall have a higher tendency to produce negative damping compared with sections experiencing deep dynamic stall.
文摘泰州自2015年6月24日起宣布入梅以来降水不断,其中伴随着多次暴雨到大暴雨过程。该文利用micaps常规观测资料、卫星云图等资料,对6月27日在泰州中南部出现的大暴雨进行分析,通过对大尺度环流场、物理量场和中尺度系统的分析,得出本次暴雨是在典型的梅雨期三阻形的形势下[1],受850 h Pa和700 h Pa切变线和地面倒槽的共同影响造成的,水汽条件和热力条件都有利于暴雨的发生和持续,地面中小尺度辐合系统是这次暴雨的触发机制。
