Effect of turbulent dissipation on the dynamics of dam break flow

Uzawa, Ken; Watanabe, Tadashi*

To prevent anomalous events of equipment and structures in a spent fuel pool from occurring, it is essential to comprehend overflow of water and fluid pressure caused by sloshing. For this purpose, it is necessary to quantitatively evaluate turbulent dissipation near water surface and inner structures instead of an empirical value which depends on size of each pool. Therefore, we test the efficacy of turbulence models by performing numerical simulation of dam break phenomenon as an elementary process of a sloshing to evaluate turbulent dissipation based on action mechanism. In this research, we derived a conservation equation of turbulent kinetic energy of RANS models and compared contributions of pressure, gravity and turbulent dissipation terms to the kinetic energy. As a result, we demonstrated that turbulent dissipation term is a predominant factor on the dynamics of dam break flow and turbulent dissipation is overestimated in eddy viscosity model.