A Research About Wind Environment Human Comfort In Consideration Of Mechanical And Thermal Effects

When people are doing activities outdoors,they are often influenced by wind.When wind speed is too high,it may cause the difficulties for human activities,or under low temperature,it may excacerbate cold sensation of peole.These phenomena are called human discomfort.Nowadays,intensive high buildings are gradually increasing.Around high buildings and narrow passages,the amplification of local wind speed may occur,which severely influence human comfort.Wind effects to people are simultaneously influenced by mechanical effects and thermal effects.Previous studies have mostly considered a single mechanical or thermal effect.Therefore,it is of great significance to synthetically study the mechanical and thermal effects of wind on human beings and to establish the human comfort criteria in wind environment with multiple factors.In this paper,we do research about wind environment comfort,the innovations are found in the following four aspects.:Firstly,considering the mechanism of the mechanical effect of wind,a wind tunnel experiment was designed to study mechanical e:ffect comfort.Combining with the questionnaire,the threshold of wind speed was analyzed when people began to appear mechanical discomfort under different modes of activity.Comparing the experimental data with the previous criteria,we found that the wind speed threshold of comfort obtained from this wind tunnel experiment is on the high side.Secondly,Based on physiological equivalent temperature model,standard effective temperature model and multipal linear model,the thermal effect of wind on human is studied,and the comfort of typical high and low temperature environment is analyzed.The three models all show that the wind speed has a favorable effect on comfort when the temperature is relatively high,while the wind speed has a negative effect on comfort when the temperature is relatively low.By using physiological equivalent temperature model,standard effective temperature model and multipal linear model,human comfort in typical high and low temperature climatic conditions in Beijing was evaluated.The results show that the standard effective temperature model has the most comfortable days at high temperature and the multipal linear model has the most comfortable days at low temperature.Thirdly,The comfort criterion considering both mechanical and thermal effects is studied.The results show that different aspects are given priority in different temperature ranges.That is to say,under high temperature conditions,not only should the wind speed be large enough to satisfy the comfort condition of thermal effect,but also the upper limit of wind speed should be limited to satisfy the comfort condition of mechanical effect.When the temperature is moderate,the thermal effect comfort condition is good,and the upper limit of wind speed should be limited to meet the mechanical effect comfort condition.At low temperature,the wind speed should be limited to meet the comfort condition of thermal effect.When the comfort condition of thermal effect is satisfied,the comfort condition of mechanical effect is automatically satisfied.Last but not least,the issure of wind comfort around buildings is studied.Through wind tunnel test,the wind speed distribution around the building is measured.Combining the test results with the meteorological data in this area,humarn comfort around the building is evaluated quantitatively by using the comfort criterion in this paper.The results show that high wind speed is easy to occur at the corners of the buildings and between the buildings.The daily comfort analysis in the most disadvantageous position of wind speed shows that more than half of the days in a year are in uncomfortable conditions.