A NUMERICAL STUDY OF EFFECT OF INITIAL CONDITION ON LARGE EDDY SIMULATION OF THERMAL PLUME

Abstract

Large eddy simulations of thermal plume in two different scenarios have been carried out using a self-developed parallel computational fluid dynamics (CFD) code, SMAFS (Smoke Movement And Flame Spread), with subgrid-scale turbulence modeled using the Smagorinsky model. Two different initial conditions were used in the simulations, and the results were compared to show that the initial condition has a significant effect on the prediction of the plume's evolution behavior. The filtered governing equations were discretized using the finite-volume method, with the variables at the cell faces in the finite-volume discrete equations approximated by a second-order bounded QUICK scheme and the diffusion term computed based on the central difference scheme. All the computations were explicitly time-marched, with the momentum equations solved based on a second-order fractional-step Adams-Bashford scheme and the enthalpy computed using a second-order Runge-Kutta method. The Poisson equation for pressure from the continuity equation was solved using a multigrid solver.