Work based on both water model experiments and numericalinvestigations is presented. Basic flow pattern in a continuousslab casting mould adopting a BSP type nozzle is studied bynumerical simulation performed by the in-house code ofVisual Cast II, hiring the k-ε model, with results validatedby water model experiments. The structure of turbulence inthe mould is further studied by LES. The preliminary resultsreveal a certain match on transient flow patterns with thewater model experiments.