It is well known that water-related accidents frequently occur around river structures such as weirs. The simulation below shows a person being drawn underwater by a vortex generated behind a bridge pier.

Nakamura Takashi Lab. @Yokohama, Institute of Science Tokyo
Department of Transdisciplinary Science and Engineering, School of Environment and Society
It is well known that water-related accidents frequently occur around river structures such as weirs. The simulation below shows a person being drawn underwater by a vortex generated behind a bridge pier.