Jack Cermak, one of the first engineers to use wind tunnels to study the impact of wind on tall buildings, has died. Dr. Cermak consulted on hundreds of projects, including the World Trade Center towers and the Sears Tower (now the Willis Tower).

Dr. Cermak was 89. He had been blind and bedridden after a stroke in 2006, according to the New York Times.

Dr. Cermak established the Fluid Dynamics and Diffusion Laboratory at Colorado State University in 1959, featuring a new form of wind tunnel.

“Previous wind tunnels were built primarily to test airplanes and missiles and had wind coming in from only one direction and at a constant speed,” the New York Times reported “By contrast, Dr. Cermak’s tunnel, which was roughly 10 times as long as aeronautical tunnels, could produce vertical wind currents and simulate powerful gusts.”

Dr. Cermak’s tunnel was called an “atmospheric boundary layer tunnel because it represented the layer of the atmosphere closest to Earth,” The Times reported.

The tunnel “changed the way buildings, bridges and other structures were built,” according to The Times. “Engineers could put a model of a structure in the tunnel and calculate the potential impact of wind on the design accordingly.”

In 2000, the American Society of Civil Engineers created the Jack E. Cermak Medal, recognizing Dr. Cermak’s lifetime of achievements in the field of wind engineering and industrial aerodynamics. Winners of the ASCE’s Jack Cermak Medal include Peter Irwin, a member of the CTBUH Board of Trustees, who was honored in 2007.