Abstract
The motion of a 2-D heavy turbulent thermal as well as a horizontally propagating density flow subsequently formed after impinging on the bottom is studied by large eddy simulations (LES). The governing equations, which consist of the filtered 2-D Navier-Stokes equations and mass conservation equation, are solved using the combined cubic spline (CCS) scheme. The eddy viscosity is evaluated by the Smagorinsky model.
The comparisons of computational results with experimental results show that the motion of both falling and horizontal propagating stage is well simulated by the present numerical model. The added mass coefficient Am for the thermal is estimated as 0.6, based on numerical simulation. The good agreements between experimental, computed and theoretical results of half width, average buoyancy and mass center velocity of the thermal are achieved. The numerical experiment reveals that motion of the thermal is dependent on the initial volume of dense fluid, even if initial buoyancy remains constant.
