Why does an umbrella turn inside out in strong winds: Bernoulli's law

Why an umbrella turns inside out in strong winds: Bernoulli's Law

In rainy weather, with strong gusts of wind, even the best umbrella invariably strives to turn inside out. The problem is familiar to everyone, but have you ever thought about why this happens?

There is one theory (without formulas)

To answer this question, you need to turn to the theorem of the Swiss scientist Daniel Bernoulli (don't worry, there will be no formulas). The physicist found that air, which moves faster in one place than in the surrounding space, creates a vacuum. Imagine that you are walking in the rain, holding your umbrella horizontally, and the wind is blowing in your face. Since the umbrella has a convex shape, the airflow, colliding with it, is divided into two parts.

One part of the stream flows around the convex side, and the second – the lower one, that is, the upper stream overcomes a greater distance to connect with the lower one.

Accordingly, the speed of the first stream is higher than that of the second. And if so, then the wind pressure over the convex part is lower than under the lower one. This difference in pressure is what turns the umbrella inside out.

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