The
destruction of southern Louisiana by flood water is a thing of
beauty. Not in reality, of course; that would be a terrible calamity.
But on Joannes Westerink's computer screen it appears as graceful
swirls of red, yellow and blue undulating in a green sea, morphing
over time across a map of the coast. The image, which could be
abstract art, is in fact an animated graph of what would happen
to the Louisiana coastline from a hurricane-generated storm surge.
The undulating colors signify the depth of the flow, increasing
from yellow to red.
"You can see this 10- to 16-foot wave shoot up the Mississippi
River," the Notre Dame associate professor of civil engineering
says. "That's the level of detail we can get with this computer
model," which is perhaps one of the best tools to minimize the
effects of such a natural disaster.
The image was created by an artist named AdCirc, an abbreviation
for Advanced Circulation model, a complex computer program developed
by Westerink and colleagues at the University of North Carolina
- Chapel Hill to "solve equations of motion for a moving fluid
on a rotating earth." The software, which is still being refined
after 16 years, can be used to solve a variety of engineering
problems, including flood-control design, pollution spread and
silt.
At the core of AdCirc is an analytical technique more commonly
used in structural engineering than in the study of fluids. "With
this we can convert partial differential equations, which mathematicians
can't solve, into algebraic equations that can be solved, and
that allows us to analyze coastal flooding problems with a very
high degree of resolution," Westerink explains.
Besides being used by Louisiana State University researchers
to predict the effect of hurricane storm surge, AdCirc has been
used by the U.S. Army Corps of Engineers to help design levees
for flood control along the Mississippi River. The newest version
of the software makes 7.5 million calculations every two seconds
to create accurate graphic animation of water flow.
(April 2005)
