The control of flows in molten metals is utilised in various industrial processes, such as the continuous casting of steel, to improve the quality of steel slabs. Numerical simulations combined with model experiments by the use of opaque low-melting alloys are performed to get a better understanding of the interaction between the magnetic fields, the induced Lorentz force and the melt flow. Ultrasound Doppler velocimetry is a suitable measurement technique for flow mapping in opaque mediums. We present the phased array ultrasound Doppler velocimeter (PAUDV), which is a further development of our ultrasound array Doppler velocimeter (UADV), with the capability to shape and steer the acoustic field. This allows novel measurement methods such as the time reversal (TR) technique. In this paper we demonstrate numerical simulations of TR experiments with respect to the PAUDV. Especially, time and spatial focussing characteristics are shown.