چكيده به لاتين
Urban aerodynamics is a branch of wind engineering science to study wind at pedestrian level and its effects on human comfort, pollution dispersion, natural ventilation, wind flow regime on different topographies and also over urban area and buildings. Studying in the above field, due to its interdisciplinary nature, requires the simultaneous cooperation of architects and urban engineers, mechanical engineers, and hydrometeorologists. Different combinations of air pollutants, their dose and time of exposure have acute and chronic effects on human health and cause various cancers. The concentration of pollutants around buildings is affected by atmospheric parameters such as wind speed and direction, changes The temperature increases with the height above the ground, relative humidity, etc., as well as the characteristics of the building, such as the height of the buildings and the distance between them, and topographical factors. The city of Karbala is one of the cities that visitors and tourists come to in large numbers from many countries during the year, especially millions of visits, including Arbaeen pilgrimage, Shaban pilgrimage, Ashura pilgrimage and others. Due to the geographical location of the city of Karbala, it is exposed to variable air currents throughout the year. It also suffers from harsh environmental conditions that spread pollution in this area. In addition to its low altitude above sea level, it is difficult for pollutants to escape through the air. Considering that this city is crowded most of the time, the tendency is to investigate it from the design aspects of building dispersion and the effect of wind movement on them in Al-Haramain area as the most important areas of this city. In this study, we conducted 28 cases, five cases for validation using a considered valid article, we also conducted two other cases of how buildings are arranged in different cities. After that, we examined 21 specific cases in the city of Karbala, including the buildings of Al-Haramain and the area between them. This area has been investigated in several ways and so far no tribal researcher has done such a study in this area. We discussed the studied area in terms of several parameters and location design, and so far no other researcher has done this study. In this research, it is for the holy city of Karbala, especially in the area between the Two Holy Harams and the Two Holy Harams. We will carefully examine the effect of changing wind speed on physical factors and, as a result, its effect on the air quality of this area. We will also examine the effect of changing the wind angle on these factors that we mentioned above. Then we will examine the effect of changing the shape of the studied area on these factors and the effect of all these on the air quality of the area between the two mosques. Then we extract the values of drag force and drag coefficient for all the previous cases above and we also discuss the impact of these extracted values on air quality. Finally, our study helps us to know the factors that help to reduce and disperse pollution in this area of our study. The results of the study show that the effect of increasing speed with altitude, while increasing the altitude, we saw a decrease in pressure and temperature. The changes of these values were investigated in variable wind speed and with different entry angles. Increasing the angle plays an important role in increasing the air movement and its pressure inside the area, and at the same time, the heat is dissipated. The shape of the area between the two mosques in the presence of trees has a major role in increasing air movement, because it was very important in terms of reducing pressure forces and heat dissipation. Also, with the different formation of the building surface, they affect the values of the drag forces. Where we noticed the increase of these forces in case of increasing the speed and entry angles, especially in the absence of trees.
