Having a stable process is a key figure to control uniform solidification and cleanliness of product in a continuous casting mould. Unfortunately, the flow in a continuous casting (CC) mould can naturally oscillate. Nowadays, there is no validated mathematical model to describe flow oscillation in a CC mould and it is not acceptable to limit the CFD results only to steady state situations when new configurations have to be numerically tested. The aim of this project is to extend the use of recent commercial packages in Fluid Dynamics to unsteady situations, so it will become possible to quantify the influence of some modifications on the process stability. The industrial objective is to limit by about 20% undergraded steel due non-symmetrical and unstable flows in CC moulds.