Evolution of the Pair of Rectilinear Laminar Vortices in a Stratified Atmosphere

The process of entrance of a pair of laminar rectilinear vortices into an atmospheric layer with stable stratification is modeled by solving numerically the two-dimensional time-dependent Navier-Stokes equations in Boussinesq's approximation. The solution is obtained on an 200x200 uniform grid using an explicit finite-difference scheme at a flow Reynolds number of Re=10⁶ and a temperature anomaly gradient of 2K per 100m height increment. The computations have shown that at the initial phase of the immersion of the vortex pair into the stratified layer, a retardation of their descent is observed, then vortices bring together and the rate of their descent become higher.