Numerical Simulations of Wall Jets.

摘要: Abstract : This document summarizes the three year investigation of transitional and turbulent wall jets using direct numerical simulation (DNS) large eddy (LES). Towards this end, a three-dimensional, incompressible Navier-Stokes code developed in our research group for DNS boundary-layer transition was adapted to jet geometry. The is based on spatial model fourth-order accurate. For LES, Smagorinsky subgrid-scale turbulence explicit accurate compact filtering were incorporated. As an initial condition, base flow close Glauert's similarity solution laminar employed. forced by blowing suction through slot wall. Periodic forcing used investigating primary secondary instabilities (Re=2OO) We discovered competing two-dimensional (2-D) three-dimensional (3-D) instability mechanisms which can be influenced significantly type forcing. 2-D large/amplitude produces coherent structures reduce shear but may lead ejections vortices from even detachment jet. Additional 3-D weakens these (especially near-wall region) thus prevent vortex ejections. In LES jets, rapid breakdown triggered random Despite purely forcing, still emerge free layer-like outer region, indication strong A fully mean compares well with experiments obtained higher Reynolds numbers (Re=2OOO).