Darryl James is the vice provost of institutional effectiveness and is a professor of mechanical engineering at Texas Tech. James was able to explain what VorTECH is and what it does.
“VorTECH simulates tornado like winds,” James said. “The idea is trying to look at what the loading is on buildings as a result of tornadoes. We don’t produce a real tornado, but mechanically, we can simulate certain types of tornadoes and that is where we started.”
James said one purpose of VorTECH is trying to understand the loading on structures, particularly low-rise structures like houses.
“There is an existing code that describes the requirements to build a house,” James said. “Part of that is the wind loading, but tornadoes aren’t included in that, and tornadoes blow structures much differently. That is what we are trying to understand, how a tornado loads a low-rise building and how it is different from straight line wind.”
James said that around 90 percent of tornadoes have an estimated wind speed of less than 150 mph. Those wind speeds are the characteristics that can be simulated using VorTECH.
They work with atmospheric scientists like Chris Weiss. The atmospheric scientists gather data of what a velocity profile looks like and use VorTECH to attempt to mimic the wind profile the atmospheric scientists observed in nature, James said.
Chris Weiss is an atmospheric scientist and professor at Tech. Weiss described in more depth what a tornado genesis is.
“We are trying to understand how tornadoes form, and that is what we call a tornado genesis,” Weiss said. “It boils down to producing the initial tornado vortex, and the matter of maintaining it once it is developed.”
Weiss said the data they are looking for includes what storms will produce a tornado and understanding how long and how strong those tornadoes will be.
The vortex simulator allows the atmospheric scientists to artificially produce tornado like vortices, Weiss said.
“We have a big exhaust chain at the top that sucks air upwards and that simulates the updraft of the tornado,” Weiss said. “They have these little veins around the perimeter that you can adjust the angle of attack of the flow near the surface. Basically, it can create a lot of circulation by adjusting the levers on the sides and then there is the updraft in the center.”
Weiss said the simulator does not give any context for storm scale, but it can give a very reliable representation of the tornado vortex itself.
VorTECH can replicate winds found in strong tornadoes. To simulate strong tornadoes, they generate a downward motion in the center and the single vortex that existed before will break down into four or five individual sub vortices that rotate around a common center, Weiss said.
DeLong Zuo, an associate professor of civil engineering and is the technical director of the National Wind Institute at Tech, explained what is being done with VorTECH and why tornadoes cause a great deal of damage.
“VorTECH doesn’t actually produce powerful wind,” Zuo said. “The wind speed is just one part of the picture; tornadoes cause damage because of high wind speed. It is also because the wind swirls, so you create a pressure field that can cause a lot of damage. What we are trying to do in VorTECH is we are trying to recreate the exact mechanism of a tornado because we cannot create the temperature profile of a tornado. We are just trying to reproduce the mechanical flow of the air.”
Zuo said VorTECH can create a tornado-like wind, but it is not the exact same thing as a tornado. However, VorTECH is still useful to study how tornadoes can create damage.
The wind speed created in VorTECH is not powerful, Zuo said. VorTECH can create wind speed up to 25 mph as opposed to an actual tornado that has a wind speed of 200 mph, VorTECH creates the wind at a scaled level.
“For example, there is 25 mph wind that creates a specific amount of force,” Zuo said. “We can then use that specific amount of force to calculate what would happen if wind speed was at 200 mph and what that force will be.”
Zuo said VorTECH will be able to help with the building codes for new structures, but there may be a possibility for reinforcing existing structures. This and making sure society can be resistant to tornado hazards, it the goal of VorTECH.