Improvement of an LRN two-equation turbulence model reflecting multi-time scales

It is well known that turbulence energy is overpredicted by the linear k– ε model at the stagnation point. This problem causes inadequate predictions of the flow field. In this paper, to evaluate the performance of a low-Reynolds-number (LRN) type turbulence model for flows on a complex wall shape, we carried out simulations of flows around various wall shapes. Based on this evaluation, we improved the model by introducing a time scale based on the velocity gradient parameter. The proposed model is evaluated in four complex turbulent flows, i.e., forward-facing step, two-dimensional block, two-dimensional hill and three-dimensional block flows. The results, together with the proposed model, are in good agreement with the experimental data.