[Science] The physics behind an odd-looking 'stormproof umbrella' from the Netherlands

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There are few places in the world more hazardous for umbrellas than the Netherlands, a country under constant assault by stiff winds and pelting rain.

 

Created by a Dutch student in 2006, the Senz umbrella is designed to redirect gusts of wind. The umbrella is popular in Europe but remains relatively unknown in the United States. [Photo provided by Senz]

 

Like many Dutch natives, Gerwin Hoogendoorn had grown accustomed to replacing broken umbrellas after storms. But after losing three umbrellas in a week Hoogendoorn, then a master's student studying industrial design and engineering, decided he'd had enough.

 

"After doing some research I discovered 1.1 billion umbrellas are thrown away each year — the equivalent weight of 70,000 elephants," said Hoogendoorn, 38. "I was fed up, and I decided I had to solve this problem."

 

After analyzing dozens of broken umbrellas he'd collected from trash bins after rainstorms, Hoogendoorn had an epiphany: The key to designing a better umbrella wasn't blocking the wind but using it to his advantage. A year-round windsurfer since age 8, Hoogendoorn realized he understood this concept instinctively.

 

With little more than some glue and his grandmother's sewing machine, an early prototype of the Senz umbrella was born. Capable of withstanding gusts up to 70 mph, according to the company, the aerodynamic umbrella looks like some combination of a Stealth bomber and a Batman cape and is designed to stabilize in high winds instead of crumpling.

 

Nine days after going on sale in October 2006, Hoogendoorn and two partners who brought the device to market already had sold 10,000 umbrellas, running out of stock completely. Now Hoogendoorn's "stormproof" umbrella has become a regular sight on Dutch streets.

 

Umbrellas range from pocket-size to contraptions large enough to cover your deck and have changed little in several thousand years. References to "parasols" date to ancient Egypt, Greece, India and Rome.

 

"Since the appearance of first silk umbrellas in China, they represented true works of art and were because of that limited only to wealthy merchants, noble families, and royals," according to Umbrellahistory.net. "Created from frames of mulberry bark and bamboo that is at least five years old, Chinese workers painted the silk top with various designs of dragons, nature, landscapes, animals, figures, flowers, scenes from their mythology, and writings."

 

The problem with most umbrellas, as any storm survivor will attest, is that an umbrella's hinges — which give it retractability — are also its weakest point, making it vulnerable to strong winds that fill the canopy. If a powerful gust of wind doesn't flip an umbrella over entirely, it's likely to break the hinges and turn it inside out.

 

Some Senz users have complained that its odd shape makes it difficult to store and unable to shield more than one person at a time from rain.

 

Hoogendoorn designed the Senz to redirect the wind, allowing the umbrella to float on the strong gust like a kite. He also removed hinges from his design and replaced them with sturdy ribbing that's nearly impossible to turn inside out.

 

When wind rushes beneath the Senz, the umbrella stabilizes instead of flipping. The company has demonstrated the umbrella's strength by placing employees in wind tunnels and turning them on full blast.

 

The front of the umbrella angles upward so the user's view isn't obstructed and the Senz lacks the pointed tips that put pedestrian's eyes at risk of being poked. The handle allows the umbrella to turn on its own when it encounters wind.

 

Hoogendoorn claims he can hold the umbrella with only two fingers without trouble in winds up to 40 mph.

 

"Our umbrella is different," Hoogendoorn said. "If the wind gets underneath, then its catches the backside of the umbrella, causing it to turn into the same direction of the wind. This is what you want because the rain is almost always coming from the direction of the wind.

 

"Like a windsurfer," Hoogendoorn added, "the idea is to use the wind to your advantage."

 

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