Abstract: The extensive investigations on the flow fields with k-ε mathematical model of turbulence and water model are presented. A quite different flow pattern from ordinary caster was found because of mild curvature of mold and strong jet from enclosed nozzle. The typical difference is the unsymmetry of flow whose recirculation zone on wheel side is larger than belt side and extends as long as 4 times the mold width. Another feature is that maximum speeds near walls are in recirculation zones and their values are 2.52 (wheel side) and 2 (belt side) times casting speed respectively.