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Nowadays, the famous tourist attractions are becoming more and more popular for people from all over the world. Thus, to ensure the safety of tourists is a tough task in such crowded area. The study of pedestrian's characteristics in crowd movement is essential for safety management. In this article, both uni- and bidirectional observational experiments were conducted to quantitatively analyze the movement properties of pedestrians in a zigzag corridor which is located in a tourism area named Yuyuan business district in Shanghai. Several phenomena have been found during the tourists' movement process: congestion at boundary, competing and bypassing behavior, and flow gap. As indicated by the transit time of pedestrians in both uni- and bidirectional scenarios, pedestrians in bidirectional pattern (>10 s) spend more time on going through the corridor than that in unidirectional one (<10 s). Besides, the fundamental diagrams in both uni- and bidirectional scenarios are significantly different from data in a controlled experiment, and obvious differences are observed within the density regime from 1.5 to 2.5 ped/m2 between the uni- and bidirectional scenarios. In addition, spatial distributions of density and velocity demonstrate that pedestrians would like to cluster at the boundary of straight corridors in both uni- and bidirectional scenarios. The results could enrich the database of fundamental diagrams, and then be used for model calibration by taking the actual situation into consideration in similar scenarios. [ABSTRACT FROM AUTHOR]

Owing to the limited installation space and duct size, coupled fittings are common in the duct systems of buildings. The coupling effect leads to changes in drag and fan energy consumption. This study investigates duct drag and flow field characteristics under coupling conditions. Experiments and numerical simulations with the Reynolds stress model are conducted. Flow field changes, flow field deformation, and drag changes in the duct are analyzed. Regardless of the coupling form, the velocity near the inner arc is fast, whereas that near the outer arc is slow. Under three different coupling connection conditions (S-shaped, L-shaped, and U-shaped), the outlet velocity gradient of the U-shaped coupling connection is the least obvious. After the fluid flows through the bend, a significant centerline velocity reduction can be observed, even greater than that in the bend. The lowest centerline velocity lies within the range of 2.5 D to 4.5 D after the bend. Coupling connection has an insignificant effect on upstream duct resistance. The resistance of single bend is less than that of the downstream bend for the coupled bend and greater than that of the upstream bend under coupling conditions.Practical application: Coupling effect is common in practical application of ventilation engineering. This effect leads to the change of fluid resistance loss of ducts and pipes. However, few researchers focus on this effect. This study finds that regardless of the coupling form, the velocity near the inner arc is fast, whereas that near the outer arc is slow. It means the guide vane should be set near inner arc. L-shaped coupling connection has the largest downstream piping resistance. The resistance of the downstream piping under S-shaped coupling is the least, thus L-shaped coupling connection should be avoided as far as possible in practical application. [ABSTRACT FROM AUTHOR]