Numerical solution of lock-release gravity current with viscous self-similar regime

Lock-release gravity currents with a viscous self-similar regime are simulated by use of the renormalization group (RNG) k - epsilon model for Reynolds-stress closure. Besides the turbulent regime with initially a slumping phase of a constant current front speed and later an inviscid self-similar phase of front speed decreasing as t(-1/3) (where t is the time measured from release), the viscous self-similar regime is satisfactorily reproduced with front speed decreasing as t(-4/5), consistent with well known experimental observations.