The Development and Analysis of the Horseshoe-Shaped Vortex in the Near-Wall Region of Turbulent Boundary Layer

摘要

The low-Reynolds-number full developed turbulent flow in channels was simulated using Large Eddy Simulation with the preconditioned algorithm and the dynamic subgrid-scale model, with a given disturbance in inlet boundary, after a short development section. The inlet Reynolds number based on momentum thickness was 670. The computed results showed good agreement with DNS, which included root mean square fluctuated velocity distribution and average velocity distribution. It was also found that the staggered phenomenon of the coherent structures was caused by subharmonic. The results clearly show the formation and evolution of the horseshoe vortex in the turbulent flow, including the symmetric vortex legs of horseshoe vortex structure and one-side leg of horseshoe vortex. Based on theses, the development of the horseshoe-shaped coherent structures was analyzed in turbulent boundary layer.