TURBULENT MIXED-BOUNDARY FLOW IN A CORNER FORMED BY A SOLID WALL AND A FREE-SURFACE

Results from a joint numerical/experimentaI study of turbulent flow al ong a corner formed by a vertical wall and a horizontal free surface a re presented. The objective of the investigation was to understand tra nsport mechanisms in the corner. Numerical simulations were conducted at NRL to obtain data describing the dynamics of the near corner regio n. The Reynolds number for the simulations was Re-theta approximate to 220. Flow visualization experiments conducted in the Rutgers free sur face water tunnel were used to initially identify coherent structures and to determine the effect of these structures on the free surface. T ime-resolved streamwise LDA measurements were made for Re-theta approx imate to 1150. The most significant results were the identification of inner and outer secondary flow regions in the corner. The inner secon dary motion is characterized by a weak slowly evolving vortex with neg ative streamwise vorticity. The outer secondary motion is characterize d by an upflow along the wall and outflow away from the wall at the fr ee surface. Additional salient results included observations of surfac tant transport away from the surface in cores of vortices connected to the free surface, intermittent energetic transport of fluid to the su rface, and attenuation of streak motion by the free surface.