Comprehensive model of upper human body clothing ventilation in standing and walking conditions

The ventilation of the microclimate air of the clothed human body segment is a result of (1) the air flow from the environment through the clothing open apertures, (2) the penetration of the porous clothing, or (3) air flow originating in the microclimate of the other clothed body parts. The microclimate air flow at the connections of clothed segments is named the inter-segmental ventilation and constitutes a real physical boundary condition that leads to ventilation of connected segments. In this study, a simplified electric circuit model is developed to estimate clothing ventilation based on the analogy between the air flow in the microclimate air layer and an electric circuit composed of resistance and inductance elements. The model takes into account the inter-connection between the segments for the clothed human upper part driven by difference of pressure in the microclimate air of the trunk and the upper arms. The developed model is validated using the tracer gas method applied on a walking manikin placed in a climatic chamber under windy conditions. Good agreement was found between predicted segmental ventilation and the experimental values with a maximum error of 16%. It was found that the inter-segmental ventilation is significant at high relative velocity for permeable clothing and increased with the increase in the relative velocity constituting about 30% of the arm ventilation and 14% of the trunk ventilation.