Buoyant Mixing Processes Generated in Turbulent Plume Arrays

Resumen

Turbulent mixing is a very important issue in the study of geophysical phenomena because most fluxes arising in geophysics fluids are turbulent. The diffusion of physical quantities in nature is due to turbulence. This is a key factor in the study of atmospheric phenomenae, specially at the planetary boundary layer. We study turbulent mixing due to convection using a laboratory experimental model with two miscible fluids of different density with an initial top heavy density distribution. Mixing is produced by the evolution of a two-dimensional array of forced turbulent plumes. Measurements include density data and flow visualization. The conclusions of this experimental model relate the mixing efficiency and the volume of the final mixed layer to the Atwood number, ranging from 0.010 to 0.134. We find that the number of plumes diminishes, the mixing efficiency reduces. We performed additional experiments releasing a fixed volume with negative buoyancy in a lighter fluid as a line of plumes (from one to nine) with a fixed Atwood number of 0.03, measuring the height of the final mixed layer as functions of the number of plumes and the available mixing volume.