Numerical study of the stratification erosion benchmark for NPPs containment using CFD code GASFLOW-MPI

•The stratification erosion process is analysed and compared with the THAI TH-20 benchmark.•Three well-known turbulence models are employed to evaluate their performances.•The LES and DES models could capture time histories of helium concentration accurately.•The k-ε model predictions are always delayed due to its overestimating turbulence mixing in the stratified layer.