Abstract
Regeneration of quasi-streamwise vortices is investigated using a data base obtained by high-resolution LES(Large Eddy Simulation)for channel flow. It has been revealed that quasi-streamwise vortices are regenerated both at the upstream of the upstream end of a parent vortex and at the downstream end of a parent vortex. In both cases, the new vortex has a vorticity of opposite sign to that of the parent vortex and comprises a chain line of vortices in the flow direction with the parent vortex, which is one of the basic organized structures in the near-wall region. It has also been revealed that the main contribution to the generation of new vortices at their infant stage is the tilting of wall-normal vortices, and that to their sustenance at grown-up stage is stretching effect.
