Time-resolved particle image velocimetry for cross-ventilation flow of generic block sheltered by urban-like block arrays

摘要

In this work, time-resolved particle image velocimetry is used for indoor velocity determination of cross-ventilation flow sheltered by urban-like arrays, to elucidate the instantaneous and statistical characteristics of the velocity fields. Combinations of two opening positions relative to the main stream flow and two surrounding array types are considered, yielding four cross-ventilation flow cases for comparison. For the streamwise window condition, the instantaneous velocity distributions differ significantly according to the outdoor block arrangement. Intermittency of the flow introduction through the windward opening and the indoor flow distributions are also confirmed based on temporal variation of the velocities. These differences in flow distribution are statistically correct according to the temporally averaged flow distributions. For the lateral window condition, instantaneous flow introduction is found to occur intermittently and alternately through each opening. Moreover, the flow introduction angle differs according to the outdoor arrangement, for both the instantaneous and mean flow distributions, indicating the importance of the surrounding-block sheltering effects on the indoor flow distributions. In addition to this elucidation of the indoor flow characteristics, the datasets obtained in this work are valuable for validating future numerical analyses of the cross-ventilation flow of a generic block under sheltered conditions.