Turbulent indoor airflow simulation using hybrid LES/RANS model utilizing Lattice Boltzmann method

In this study the LES, RANS and hybrid RANS/LES turbulence models within the frame work of the Lattice Boltzmann method (LBM) were used to study turbulent indoor airflow. The turbulent airflow was simulated first using the LES where the sub-grid scale turbulence effects were accounted for using the Smagorinsky model. Then, the airflow was studied using thek−ɛ turbulence model in conjunction with the LBM by the addition of two population balance equations for k and ɛ. For the hybrid RANS/LES method, the near wall region was simulated using the RANS model in conjunction with the k−ɛ turbulence model, while the rest of the domain was analyzed with the LES model within the framework of the LBM. The present simulation results for the airflow showed good agreement with the experimental data and the earlier numerical results, particularly, for the LES and the hybrid RANS/LES models. The results also showed that the accuracy of the hybrid model is more than the RANS and less than the LES models. While the hybrid model predicts the large scale turbulence fluctuation velocities in the bulk of the flow, the needed computational time is less than that of the LES model and more than the RANS model.