The importance of compatible sub-grid scale and spatial discretization models on the simulation of large-scale pool fire

Abstract

Using discretization technique is one of the challenges associated with numerical modeling. In the Large Eddy Simulation (LES) method, this issue becomes more critical because it affects the sub-grid scale (SGS) model and creates errors. Using an LES method, we investigated the numerical errors and compatibility of different discretization methods with SGS in pool fire modeling. First-order, central, and second-order upwind and linear upwind stabilized transport (LUST) schemes were examined in Smagorinsky (S_SGS) and k-equation (K_SGS) sub-grid scales. First-order upwind and second-order upwind methods estimated the velocity field, temperature, and perturbation with a significant error, so that in the plume area, there was 90% error with the first-order upwind and 50% error with the second-order upwind concerning the results of the mean square horizontal velocity perturbation. With an error of 20%, the LUST method had a better agreement with the experimental results. Besides, SGS did not have a significant effect on the results of this method. However, the second-order upwind method was more consistent with the S_SGS model. To improve the results of upwind methods, Quadratic Upstream Interpolation for Convective Kinematics and Monotonic Upwind Scheme for Conservation Laws discretization methods are recommended.