Influencing factors of convective heat transfer between human body and environment under simulated and real walking conditions

Abstract

With rapid urban development and a growing emphasis on healthy lifestyles, the design and construction of pedestrian spaces have garnered increasing attention. However, existing studies focus on the effects of wind fields on static human or involve subjects walking on a treadmill to simulate walking. These methods differ greatly from the relative wind speed sources of real walking, resulting in significant deviations between existing thermal comfort models and measured results. In this study, we measured the convective heat transfer coefficients ($h_c$) by a thermal manikin at relative wind speeds (v) of 0.3 m/s, 0.5 m/s and 0.8 m/s under both real walking (RW) and simulated walking (SW) conditions, where the relative wind speed source of RW is generated by the human or manikin moving forward and SW is generated by the fan wall. Additionally, 12 adults participated in the experiments, performing both SW and RW. Subjective perceptions and skin temperature were recorded during both SW and RW. The results demonstrated significant differences in $h_c$ between SW and RW conditions, which were perceptible to participants through subjective evaluation. The increasing relative wind speed and turbulence intensity contribute to higher $h_c$. The relative airflow of RW is similar to the natural wind, which may explain some differences between SW and RW conditions. This study further derives the following fitting for free walking and provides empirical basis for future experiments.