風乾的原理

這是蒸發作用的原理，風會把衣服上的水份子帶到空氣中，因此有風吹的衣服會較快乾。

This is simply "forced convection". The moving air (wind) helps to carry the moisture on the clothes away.

Should the clothes be hung in still air, water evapourated from the clothes remains in the vicinity of the clothes. This elevates the air humidity surrounding the clothes, thus leading a lower evapouration rate for further moisture to be evapourated from the clothes. Clearly, this lengthens the drying time for the wet clothes.