Transient Analysis of Cold Winds on Exposed Skin: Reflections on the Assessment of Wind Chill Equivalent Temperatures

Abstract

A transient analysis of the human?environment thermal interaction in cold and windy environments is presented. The site selected to represent this interaction is the head?face, which is depicted as a hollow cylinder wherein heat is conducted in the radial direction. Environmental radiation effects, which are small relative to the wind-driven convection effects, as well as metabolic heat and blood perfusion effects, are not accounted for at this stage. The model is solved analytically by an integral transform. Results are used to calculate the wind chill equivalent temperatures (WCETs) for different environmental temperatures and wind speeds. The temporal variations of the calculated WCETs are contrasted against the steady-state values that are published by the weather services in North America. The inherently transient nature of this parameter is clearly demonstrated. This observation should form a basis for modifying the heretofore employed steady-state calculation method of this useful weather predictor.