Measurements of the air temperature and air velocity were carried out in four buildings without air-conditioning using a newly developed anemometer whose sensitivity allows the examination of the dynamic behaviour of air movements. Recent results describing the physical reasons of draft problems were employed in order to re-examine the correlation between air movements and draft problems in a building. From the resulting evaluation criteria follows that besides, the environmental temperature and the mean air velocity, the magnitude of the turbulent fluctuations is important .
A study was made of one hundred subjects who were exposed to air flow with a turbulence as occuring in typically ventilated spaces. Turbulent air flow is seen as more uncomfortable than laminar flow. Each subject participated in three experiments at air temperatures of 20, 23, and 26 degrees C, withvarying air velocity and turbulence intensity. Recommends a reduction of velocity limits specified in existing standards.
Characteristics of the air velocity were measured at 500 points in the occupied zone of 20 typically ventilated spaces. A relationship between the mean velocity and the standard deviation was found at four heights above the floor. The turbulence intensity varied from 10 to 70% at ankle level (0.1 m) and from 20 to 55% at head level. This is similar to the experimental conditions under which the draught chart by Fanger and Christensen was established.
Air flow in an enclosed space, whether from natural or mechanical ventilation, has generally a rather slow velocity, 0.1-0.25 m/s, but may still cause local discomfort. Tests were carried out on laminar and turbulent air flows in this velocity range. Turbulent air flow was found to always cause more discomfort than linear air flow.
This paper presents a numerical calculation method for a two-dimensional, isothermal, turbulent room air movement. In this case, the time averaged stream function-vorticity equations were represented by finite differencing approximations