Fluid dynamics of a free surface in liquid metal fast breeder reactors

Abstract In the Liquid Metal Fast Breeder Reactor, the coolant sodium has free surfaces in the vessel. The interaction between the high speed flow and the free surfaces could induce self-induced surface oscillations and bubble entrainment. Recently, several self-induced free surface oscillations caused by water jet were discovered, e.g., a self-induced sloshing, “Jet-Flutter” “Swell-Flapping” and a self-induced manometer oscillation. These self-induced oscillations were excited by the non-linear interaction between free surface and flow. In this paper, the characteristics and mechanism of these self-induced oscillations were investigated.