Professor researches destructive thunderstorms by simulating winds at FIU

When a severe thunderstorm warning pops up on your phone, lightning and rain aren’t all you should be worrying about.  

Thunderstorms can produce winds exceeding 100 miles per hour (mph), according to the National Weather Service. These winds come from tornadoes but also lesser-known events such as downbursts. 

“The problem is that we currently do not have design guidelines available in building codes and standards to help communities stay safe against downbursts," says Professor Amal Elawady, an expert on wind engineering at the College of Engineering and Computing. 

Elawady is using FIU’s Wall of Wind (WOW) to research how high-intensity winds from downbursts affect low-rise residential buildings.  

According to Risk Management Solutions, the average annual insured loss from downbursts and other severe thunderstorms in the United States is $17 billion—$1 billion higher than the average annual loss from hurricane winds. 

“The wind characteristics are different. You cannot really look at data that you get from hurricanes and downbursts the same way,” Elawady says. 

A downburst occurs when a large amount of rain, hail or air from a cloud plummits earthward, generating wind in a downward direction. Once the wind hits the ground, it spreads in all radial directions and a wind vortex forms on the edges of the storm. This causes severe wind conditions at very low heights.

These storms can wreak havoc on life and property. In 2019, a downburst killed one person and injured at least five others when a crane fell on an apartment building in North Texas, according to The Dallas Morning News. 

Elawady has configured the FIU Extreme Events Institute's WOW, a facility normally used to study hurricane-force winds, to simulate a downburst’s wind vortex.

The slow motion video below shows how a wind vortex flows during Elawady’s research.

In front of the WOW downburst simulator stands a small object, a miniature-size model of a building. This is a replica of a building at Texas Tech University that is currently used to test downbursts in nature, scaled down 20 to 1. It is loaded with more than 200 sensors to study how wind pressure is generated at different points along the structure. 

“One important difference between wind from hurricanes and downbursts is that downbursts generate a vortex before they even hit the structure, which may cause excessive suction on building surfaces. This is because of the circulation of the rolling vortex,” Elawady says. 

In the experiment, the building model rotates to recreate the effect of a downburst storm rolling by. These storms move quickly and last only a few minutes. 

The data recorded in the experiment will be compared to that of real-life downbursts obtained by faculty at the University of Illinois Urbana-Champaign and the University of Genoa. If the measurements match up, the WoW could serve as a base for further research into downbursts, Elawady says.

“The Wall of Wind is a national facility,” Elawady says. “It is open to researchers from across the nation to come and use it. It is important that we provide them with top-notch equipment.” 

Elawady’s research is funded by the Florida Division of Emergency Management and the National Science Foundation (NSF) via the Extreme Events Institute, a critical research center at FIU. Her previous research about how downburst winds affect power lines was published in an American Society for Civil Engineers manual. Elawady is an NSF Career Award winner.