  A liquid metal flow in the form of a submerged round jet entering a square
duct in the presence of a transverse magnetic field is studied experimentally.
A range of high Reynolds and Hartmann numbers is considered. Flow velocity is
measured using electric potential difference probes. A detailed study of the
flow in the duct's cross-section about seven jet's diameters downstream of the
inlet reveals the dynamics, which is unsteady and dominated by high-amplitude
fluctuations resulting from instability of the jet. The flow structure and
fluctuation properties are largely determined by the value of the Stuart number
N. At moderate N, the mean velocity profile retains a central jet with
three-dimensional perturbations increasingly suppressed by the magnetic field
as N grows. At higher values of N, the flow becomes quasi-two-dimensional and
acquires the form of an asymmetric macrovortex, with high-amplitude velocity
fluctuations reemerging.
