Icing Research Tunnel
The Glenn Research Center's Icing Research Tunnel is the world's largest refrigerated wind tunnel. During tests of a heated-air system in 2003, researchers gathered information on the effects of runback ice on aerodynamic performance. (Runback ice forms when water does not evaporate on the heated portion of the leading edge, but "runs back" to an unheated area and freezes.) The test was designed as part of a coooperative program in conjunction with the Federal Aviation Administration, industry and academic researchers.
Image credit: NASA