Today, the numerical simulation of fluid dynamic phenomena(CFD) in steelmaking applications is state of the art. Thelatest simulation results for the BOF and AOD as well asthe thin strip casting process are described. The basicinfluence of the process parameters, e.g. blowing andstirring rate, vessel dimension, location of top lance, numberand arrangement of porous plugs, on the converter meltflow and mixing time is simulated. In the case of thin stripcasting, the free melt flow on the moving belt is influencedby an induced electromagnetic field. The respective MHD(magneto-hydrodynamic) is presented.