Fast-Algorithm Development for Large-Eddy Simulation of Circular-Jet Turbulence

摘要

The research reported herein addresses a theoretical investigation of a free, turbulent round jet issuing into a quiescent ambient, and deals with asymptotic analysis for farfield development and subgrid-scale turbulence modeling and with computational considerations for a large-eddy simulation. Higher-order asymptotic analysis of the fully developed downstream region has uncovered new information for the stress- and pressure-function solutions in the exterior region. The analytical predictions of the centerline decay of the mean axial velocity and those of the radial distributions of the axial and radial mean-velocity components and the shear- and normal - stress components compare well with available experimental data and provide the needed farfield boundary conditions for the large-eddy computations. The numerical considerations for the latter examine the construction of hybrid-difference methods that preserve weak but persistent unsteady features, the two-dimensional jet, and dual-variable algorithm for simulating incompressible three-dimensional flows. Asymptotic structure, Farfield development, Free jet, Large Eddy simulation, Round jet, Subgrid scale turbulence, Turbulence modeling. (mjm)