Modeling of free surface vortex with realistic downward velocity distribution

Ito, Kei; Ezure, Toshiki ; Ohno, Shuji  ; Kamide, Hideki 

A free surface vortex is considered as one of important phenomena which may cause gas entrainment (GE) in sodium-cooled fast reactors. In this study, a new theoretical vortex model with realistic downward velocity distribution is proposed. This model is derived from the axisymmetric Navier-Stokes equation as well as the Burgers model, but the downward velocity distribution is considered. As the verification, the new model is applied to the evaluation of a simple vortex experiment, and shows good agreements with the experimental data in terms of the free surface shape. In addition, it is confirmed that the Burgers vortex model can gives similar results to the new vortex model when the downward velocity gradient is calculated appropriately.