Effects of different CFD modeling approaches and simplification of shape on prediction of flow field around manikin

Providing a comfortable and pleasant indoor environment for the occupants is the primary objective of an efficient ventilation process. Therefore, it is important to gain a proper understanding between the interaction of airflow and the occupants which determines the ultimate ventilation strategy and as one of the final outcomes, the architecture layout itself. The CFD (Computational Fluid Dynamics) methods provide an accurate and robust tool to simulate the complex airflow structure in enclosed spaces. Among the CFD simulation approaches, the large eddy simulation (LES) and its hybrid variants such as detached eddy simulation (DES) provides the information on the flow behavior by modeling the small turbulent structures of the airflow encountered in an indoor environment. These methods are highly sensitive to the boundary conditions which are the pivotal factors in an indoor airflow modeling and its accuracy. The main objectives of this paper are: (a) to assess the performance of different LES and DES models in capturing velocity and thermal fields (b) to investigate the effect of manikin's shape on the accuracy of predictions. Three LES SGS (sub-grid scale) and one DES models are applied in this study considering the cases with and without the radiation from the manikin. Moreover, the effect of simplifying the manikins’ geometry on velocity and thermal distribution is investigated. Results showed that a detailed manikin shape can provide more accurate predictions (4–10%) at some locations, especially those close to the manikin's body. As for performance of the applied models, Comparisons showed that ZEM and WALE models provide a better predictions of velocity and temperature fields by 3–10% at different locations.