Finite-volume computation of merging parallel channel flows by a second-moment turbulence closure model

The mixing process of turbulent shear layer developing in a plane two-dimensional channel has been numerically investigated. Under the condition of various initial shear rates as accomplished by varying the mass flow rate of the two oncoming parallel channel flows, the performance of a second-moment closure model and the k-ε{lunate} model has been examined in terms of representing the overall streamwise flow development as well as the profiles of individual variables. It is shown that the difference between the two models is largely attributable to the evaluation of the production rate of turbulent kinetic energy, the second-moment closure model ensuring a slightly more realistic simulation of the flows out of the equilibrium state of turbulent kinetic energy.