Excuse me, what is direct flow?

The so-called "cross wind" mouth means that the wind passes through two tuyeres and several winds meet here. The wind is big and fast, which is very easy to hurt people. In summer, people sweat a lot during the day, which leads to high calorie consumption, fatigue and lack of energy. Coupled with reduced diet, their resistance is relatively poor. Under the direct blowing of "through flow" at night, the heat is emitted more, the body temperature drops rapidly, the respiratory mucosa and blood vessels contract, the blood supply decreases, the disease resistance decreases, and germs take advantage of it, which is easy to make people suffer from "cold".