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

• We study the improvement of linear two-equation turbulence model.
• The proposed two-equation turbulence model includes new time-scales.
• The predictions of proposed model are evaluated in various complex turbulence fields.
• The proposed model predicts good agreement with experimental data.

It is well known that turbulence energy is overpredicted by the linear k  –εε 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.