Daily Nonpareil, Council Bluffs, IA
05-08-06
ISU project will chase tornado data to engineer better buildings
PHIL ROONEY, Staff Writer
Submitted photo - Iowa State University students are seen at work with the
tornado simulator in the school’s Wind Simulation and Testing Laboratory.
When tornadoes send you to the basement this year, Iowa State University
researchers and students will be chasing tornado data in the lab and across the
plains of Tornado Alley.
Their adventures are part of a research project to increase scientists basic
understanding of windstorms so new methods can be developed to make homes
and buildings stand up to tornadoes, microburst thunderstorms, hurricanes and
gust fronts.
The project is funded by $1 million from the federal governments 2006 Science,
State, Justice, Commerce and Related Agencies Appropriations Act.
Partha Sakar, an ISU professor of aerospace engineering, will lead the
research team which includes: Fred Haan, an assistant professor of aerospace
engineering; Hui Hu, an assistant professor of aerospace engineering; Vinay
Dayal, an associate professor of aerospace engineering; Gene Takel, a
professor of geological and atmospheric sciences and agronomy; and Bill Gallus,
a professor of geological and atmospheric sciences.
As many as eight graduate students also may be involved as Colorado-based
researcher Tim Samaras of Applied Research Associates Inc. will be sent racing
ahead of storms to take field measurements of tornadoes.
Students with storm-chasing experience and safety training are expected to join
Samaras and a team from National Geographic as they travel Tornado Alley this
month and next, Gallus said. The students will try to help Samaras deploy
sophisticated probes, including instruments and cameras in an effort to measure
the storms power as close to ground level as possible.
I think its probably a little more dangerous than a normal storm chase, but its
really not that dangerous because the people involved are so experienced,
Gallus said.
But, instead of taking pictures, the students need to put the instruments in the
storms path.
He (Samaras) aborts the mission if theres any sign of anything going wrong,
Gallus said. I think theres a fairly good structure set up here for safety.
Gallus would love it if some of the action happened in Iowa.
I would enjoy getting to be part of that group. I think it would be a thrill, he said.
The students are scheduled to be in the field for two weeks at a time, but that can
be modified depending on whats happening with the weather. Much of their work
will be centered out of Samarass Denver base.
When severe weather is anticipated, the students and Samaras will drive out to
the area where storms are anticipated and, if needed, stay in hotels.
There is one potential problem for the researchers, a possible lack of severe
weather.
The project was supposed to start Monday, but this weeks cool, calm weather
hasnt provided many opportunities for research.
Right now its rather frustrating, he said. With the exception of a couple of days,
the coming week also appears to offer a cool weather pattern; and some of the
researchers are hoping things get more active before the end of the month so
they can do their work.
Were hoping to get some good data here.
Gallus, who has chased tornadoes for 20 years, said he has seen between 40
and 50 tornadoes including a couple of close calls last year.
One of those came on Nov. 12 when a twister came within a mile of his Ames
home. He was able to videotape that one.
Then there was the small tornado that hit his office building on Sept. 8. Its wind
speed was measured at 83 mph. according to instruments on the buildings roof.
Gallus had been on that roof with some students just minutes earlier, and said
the sky was as green as any Ive ever seen. Back inside the building, the winds
sent him into the hallway where he heard windows crack as a student ran in to
report seeing the tornado.
In the lab, the research team will focus on four major projects: studying the flow
of storm winds near the ground; testing models of various structures in Iowa
States Wind Simulation and Testing Laboratory; developing computational
models using a technique called finite element analysis that will simulate how
wind storms affect buildings; and they will study new building designs that would
be resistant to wind storms.
Sarkar, the research team leader, said the group is expanding on earlier work
and hopes to apply science in a way that will improve peoples lives.
Past work largely has focused on tornadoes, but this time more attention will be
given to microbursts and gust fronts.
This is a little more comprehensive type of work, he said.
Sarkar said current building codes are based on the ability to withstand straightline winds up to 90 mph. You can get much higher winds, he said.
Not only that, Sarkar pointed out, but rotating winds in a tornado will react
differently with a building than straight-line winds and place a different wind load
on the structure.
For example, a 150 mph tornado wind has roughly three times the force of a 90
mph straight-line wind, Sarkar said.
The researchers want to assess what kinds of wind loads different structures will
stand, and one theory that will be explored will attempt to find out if homes built
with lumber can withstand tornado winds if they are constructed in a different
form.
That could lead to changes in building codes, designs or materials, which, in turn,
boils down to the economic feasibility of the potential change.
You have to build buildings with materials that are readily available, Sarkar said.
The question is can we do incremental changes . . . or do we have to make some
drastic changes?