Experiments were carried out in a 50-m(3) cylindrical tank to determine the influence of strong momentum on the formation of large-scale gas-core vortices. Gas-core lengths were measured for varying volume flow rates and submergence depths. The critical Froude numbers were also determined and the efficiency of different vortex suppressors on the gas-core formation was investigated. The horizontal velocity field inside the vortex core region was additionally recorded using particle image velocimetry. The experimental results were used to verify numerical simulations and compared to vortex models and correlations from literature.