Analysis of the effects of dynamic mesh update method on simulating indoor airflow induced by moving objects

Abstract

Local interference flow induced by the movement of human bodies or objects indoors can directly affect breathing air quality. However, very few studies have been carried out on the flow induced by moving objects due to high experimental costs. As an alternative, computational fluid dynamic (CFD) method has been employed in predicting the flow induced by moving objects indoors. During the numerical computations, the mesh needs to be updated continuously for the moving objects behave as part of the boundary. Although the dynamic mesh update (DMU) methods have been used in the CFD method, the performances of these DMU methods vary widely, and it is still lack of analysis on the selection of the DMU methods. In this study, the DMU methods provided by ANSYS FLUENT are used for comparing the numerical performances between computational and experimental results. Five aspects of numerical performance, accuracy, mesh quality, mesh generation complexity, continuity, and computational efficiency, are discussed integrally. The results show the dynamic layering (DL) method is preferred for the case of linear movement due to the high computational efficiency and accuracy though it is difficult and time-consuming in mesh generation. Spring-based smoothing & remeshing (SS&R) method can be used when the complicated-shaped or nonlinearly moving objects are part of the boundary. Both computational efficiency and accuracy of overset mesh (OM) method are low when the moving objects are clinging to the boundary, so this method is not recommended for simulating the flow fields.