Through flow usually occurs in gaps between buildings, high walls, rooms with opposite doors and windows or similar passages. Due to the different atmospheric temperatures on both sides of air circulation, air pressure leads to the rapid flow of air, and it is also hindered by buildings, gaps, doors and windows, corridors, etc. Provide a circulation channel for the rapid circulation of air. The wind direction is generally from the sunny side to the shady side, and the wind speed depends on the temperature difference between the two sides. The greater the temperature difference, the greater the wind speed, mostly in spring and autumn.