Numerical study on head advancement of axisymmetric gravity currents

The head front location as the function of time for the axisymmetric gravity current was numerically studied in this paper. The adopted renormalization group (RNG) k – ϵ model for Reynolds-stress closure was used to character the time-dependent current with transitional and highly localized turbulence. Consistent with well known experimental observations, the numerical results show that the axisymmetric gravity current passes through two phases: an initial slumping phase in which the current head advances steadily, and a second self-similar phase in which the front velocity decreases as t - 1 / 2 .