Coupled simulation of CFD and human thermoregulation model in outdoor wind environment

Abstract

Understanding of dynamic and transient wind environment is crucial to evaluating the outdoor thermal comfort of pedestrians. The thermophysiological responses of the human body depend on both the interaction with the climate and internal thermoregulation. The coupled simulation of CFD and thermoregulation model provides a pathway to predict human responses under non-uniform conditions where local effects may dominate thermal comfort. In this work, we explore the potential of coupled simulation under outdoor environmental conditions. The thermoregulation model JOS-3, which consists of 85 nodes and 17 body segments, is used to simulate the physiological responses and the obtained mean skin temperature is fed into CFD as the boundary condition of the thermal manikin. The thermal interactions between the human and surrounding environment in the wind tunnel, represented by convective and radiant heat transfer coefficient, are calculated by CFD and serve as inputs for the JOS-3 thermoregulation model. The results exhibit that under the wind velocity of 1 m/s and turbulent intensity of 11.6%, the coupling can converge within two iterations. This is because the convective heat transfer coefficient is not significantly affected by the body skin temperature under the assigned outdoor airflow velocity, which is higher than the value in an indoor environment. The study demonstrates the workflow of coupled simulation in an outdoor wind environment and could be a useful tool for evaluating outdoor thermal comfort under different conditions in the future.