Large-eddy simulation of dual planar jet flow and heat transfer near a wall

The present work aims to study the flow and thermal characteristics of multiple planar turbulent jet configurations comprising a wall jet and an offset jet by performing large-eddy simulations (LES). The general configuration is such that the wall jet enters parallel to and along the bottom wall, while the offset jet is also aligned parallel to the bottom wall, but is positioned at a specified offset distance. The Incompact3d numerical flow solver is used to run the LES. The solution procedure is thoroughly verified with direct numerical simulation (DNS) data available in the literature on planar wall jets. The present work aims to analyze five different configurations through two sets of analysis. The first set of analysis is conducted for three different offset ratios, O R = 5 , 3 , 2 for R e = 7500 and a velocity ratio (VR) of 1. The second set of analysis is conducted for three different velocity ratios, V R = 2 , 1 , 0.5 for OR = 5, where the Reynolds numbers vary accordingly. For all cases, the Prandtl number of the fluid P r = 0.71 . A detailed investigation of the mechanism of momentum and energy transport is presented by analyzing flow and thermal statistics, the Nusselt number, turbulence kinetic energy (TKE) and energy spectra. A larger recirculation zone is observed for larger ORs, where the maximum TKE is observed. For OR = 5, the TKE dissipation at the wall scaled with inner variables is found to be 0.38 which is higher than the values reported in the single planar wall jet case in the literature.