摘要
The wake behind a circular cylinder with wavy surface was investigated using single-frame PIV technique at Re=5200. The mean flow field and spatial distribution of turbulence statistics in the nodal, saddle and middle planes were presentcd and compared with those of a smooth cylinder. The near wake behind the wavy cylinder shows pronounced spanwise periodicity of flow structures. Compated with a smooth cylinder, the vortex formation region considerably expands in the streamwise direction, particularly reaching maxi mum in the saddle plane of the wavy cylinder. However, the longitudinal vortices in the nodal plane were noticeably suppressed in the transverse direction. In addition, the wake in the nodal plane contains the peak value of turbulent kinetic en ergy and the Reynolds shearing stress due to the intensive entrainment of free flow and the momentum exchange in the spanwise direction.
The wake behind a circular cylinder with wavy surface was investigated using single-frame PIV technique at Re=5200. The mean flow field and spatial distribution of turbulence statistics in the nodal, saddle and middle planes were presentcd and compared with those of a smooth cylinder. The near wake behind the wavy cylinder shows pronounced spanwise periodicity of flow structures. Compated with a smooth cylinder, the vortex formation region considerably expands in the streamwise direction, particularly reaching maxi mum in the saddle plane of the wavy cylinder. However, the longitudinal vortices in the nodal plane were noticeably suppressed in the transverse direction. In addition, the wake in the nodal plane contains the peak value of turbulent kinetic en ergy and the Reynolds shearing stress due to the intensive entrainment of free flow and the momentum exchange in the spanwise direction.
