Numerical simulation of a variable-density mixing-layer

The development of a baroclinic secondary instability over the primary Kelvin-Helmholtz roll-up of a two-dimensional, variable-density mixing-layer is discussed. A particular attention is paid to the accuracy of the simulations by investigating the conservation of an invariant of the flow. Then, the influence of both the spatial and the temporal resolution on the development of the secondary instability is studied. It is concluded that the variable-density layer exhibits a strongly unstable region where vorticity has been intensified by the local acceleration coupled with the density stratification.