Why does the wind look stronger than usual when standing near tall buildings?

We know that wind is the movement of air flow, formed by the change of atmospheric pressure, often going from a place of high pressure to low pressure.

Building an upstream structure means blocking the normal flow of wind and often causes the following two common phenomena:

  1. Downdraught effect , meaning that when the wind hits a building, is blocked, there is no other place to go, they will be pushed down, pushed up or into the sides of the building. Downward air pressure increases the wind speed in the area below the building
  2. Venturi effect - We imagine that when the water is upside down, because of the bottle neck, the water pressure is stronger than when we use a bottle with the same head and ass size

Picture 1 of Why does the wind look stronger than usual when standing near tall buildings?
When the wind blows through the narrow range between buildings, the pressure will decrease and the wind speed increases.

In other words, when the liquid passes through the narrow position of the pipe, the initial pressure will decrease, but at the same time the velocity increases. And similarly to the wind, when the wind blows through the narrow range between buildings, the pressure will decrease and the wind speed increases.

Normally when building a building, in addition to many other calculations, one must simulate the wind model that affects the building in order to ensure the integrity and safety of the building, secondly to limit the occurrence of these phenomena.

Picture 2 of Why does the wind look stronger than usual when standing near tall buildings?
Depending on the severity of the effects, the wind on the ground can be twice as strong as when it moves high up.

The effects mentioned above could be a threat to the safety of people living and working underneath the building. Depending on the severity of the effects, the wind on the ground can be twice as strong as when it moved at a height of several tens of meters above.

For example, a wind with a speed of about 40km / h can be amplified up to 55km / h below the building. And it is known that only one wind of 60km / h is enough to blow one person away.