Scientists hope to mimic the most extreme conditions of the hurricane

The wind howls at more than 300 kilometers per hour, hitting a two-story wooden house and tearing the roof off the walls. Then comes the water. A wave 6 meters high covers the structure, knocking the house off the foundation and washing it away.

This is a horrific vision of researchers planning a new modern facility to restore the chaos caused by the most powerful hurricanes on Earth. In January, the National Science Foundation awarded a $ 12.8 million grant to researchers to design a facility that could model wind speeds of at least 290 km / h – and at the same time produce deadly, high storm surges.

There is no object that could produce such one or two gusts of strong wind and water. But this is an idea whose time has come – and not for a moment.

“It’s a race against time,” says disaster researcher Richard Olson, director of extreme research at the International University of Florida, or FIU, in Miami.

Hurricanes are getting worse because of human-induced climate change: they are getting bigger, wetter, stronger and slower (SN: 13.09.18; CH: 11.11.20). Scientists believe that the season of hurricanes in the Atlantic Ocean in 2022, which will cover from June 1 to November 30, will be the seventh season in a row with more storms than average. Recent seasons have been celebrated increasing rapidly intensifying hurricanes associated with ocean warming (CH: 21.12.20).

These trends are expected to continue as the Earth continues to heat up, researchers say. And coastal communities around the world need to know how to prepare: how to build structures – buildings, bridges, roads, water and energy systems – that are resistant to such punishing winds and waves.

To help with this training, FIU researchers lead a team of wind and design engineers, coastal and ocean engineers, computational model developers and sustainability experts from different states to work out how best to model these hippos. Combining extreme winds and water jumps into one object is unexplored territory, says Ioannis Zisis, FIU wind engineer. “We need to push the envelope,” says Zisis. But how exactly to do it, “the answer is simple: we don’t know. That’s what we want to find out. “

Preparation for “category 6”

The point is not that there have been no such extreme storms on Earth. In the last few years alone, Hurricanes Darian (2019) and Irma (2017) in the Atlantic Ocean and super typhoon Haiyan (2013) in the Pacific Ocean have brought storms with wind speeds well over 290 km / h. Such super-intense storms are sometimes referred to as “Category 6” hurricanes, although this is not an official designation.

The National Oceanic and Atmospheric Administration, or NOAA, rates hurricanes in the Atlantic and Eastern Pacific on a scale of 1 to 5, depending on their wind speed and how much damage these winds can cause. Each category covers an increase of approximately 30 km / h.

Category 1 hurricanes with wind speeds of 119 to 153 km / h cause “some damage” by cutting off some power lines, felling trees and possibly knocking down shingles or vinyl siding from the house. Category 5 storms with wind speeds of 252 km / h cause “catastrophic damage” by bulldozing buildings and potentially leaving neighborhoods uninhabitable for weeks or months.

But 5 is as much as he gets on the official scale; after all, what could be more devastating than catastrophic damage? That means even ugly storms like it Hurricane Dorian 2019which equated the Bahamas with wind speeds of almost 300 km / h are still considered category 5 (SN: 03.09.19).

“Actually, I understand that [NOAA doesn’t] sees the need for category 6, ”says Olson. But there is a difference in society’s perception, he says. “I see it as another type of storm, a storm that’s just scarier.”

And apart from the labels, the need to prepare for these stronger storms is obvious, Olson says. “I don’t think anyone wants to explain in 20 years why we didn’t do it,” he said. “We have challenged nature. Welcome to retribution. ”

Superstorm simulation

The FIU is already the owners The wall of wind, a huge hurricane simulator housed in a large hangar attached at one end by an arc of 12 massive yellow fans. Even at low wind speeds – say, about 50 km / h – the fans make a loud, alarming hum. At full power, these fans can create wind speeds of up to 252 km / h, which is equivalent to a low-category hurricane 5.

Inside, researchers populate the hangar with designs that mimic skyscrapers, houses and trees, or figures that represent irregularities and differences in the earth’s surface. Engineers from around the world visit the facility to test the wind resistance of their own creations by watching the winds blow their designs.

the yellow fans in the warehouse form the Wind Wall
Twelve fans tower over one end of the Wind Wall, a large experimental setup at the International University of Florida in Miami. There, wind speeds of up to 252 kilometers per hour allow researchers to reconstruct the conditions experienced during the low-level hurricane 5.NSF-NHERI Wind Wall / FIU

It is one of eight facilities in the national network of laboratories that study the potential effects of wind, water and earthquake hazards, which together are called U.S. Natural Hazard Engineering Infrastructureor NHERI.

The wind wall is designed for full-scale wind testing of entire structures. Another wind machine, located at the University of Florida at Gainesville, could increase turbulent wind behavior right on the boundary between the atmosphere and the earth. Next there are giant tsunamis and storm surges that mimic water waves at the University of Oregon at Corvallis.

The new facility aims to build on the shoulders of these giants, as well as on other experimental laboratories across the country. The design phase is projected to take four years, as the team considers how to increase wind speeds – perhaps with more or more fan power than the Wall of Wind – and how to combine these gusts of wind and massive water tanks into one experimental space. .

Existing labs that study wind and waves together, albeit on a much smaller scale, may offer some insight into this aspect of design, says Forrest Masters, a wind engineer at the University of Florida and head of NHERI at the facility.

This design phase will also include the creation of a scaled-down version of the future laboratory as proof of concept. A new round of financing and several more years will be needed to build a full-scale facility.

Past approaches to studying the effects of strong winds have typically used one of three approaches: conducting field observations of the effects of a given storm; construction of experimental facilities for storm recovery; and the use of computational modeling to visualize how these impacts may occur in large geographic regions. Each of these approaches has its strengths and limitations, says Tracy of Kiev-Korea, a disaster risk engineer at the University of Notre Dame in Indiana.

“In this institution, we want to combine all these methodologies,” says Kyiv-Korea, in order to get as close as possible to reproducing what Mother Nature can do.

This is a complex engineering problem, but an exciting one. “There is a lot of enthusiasm in the wider scientific community,” says Masters. “If it is built, there will be nothing like it.”

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