From left, Terry Hayes, vice president and chief technical officer of Non-Contact Technologies, LLC; Steve Arnold, technical adviser for the 717th Test Squadron, 804th Test Group, Arnold Engineering Development Complex; Dr. Phil Kreth, an assistant professor with the University of Tennessee Space Institute (UTSI); and Haley Goldston, a research assistant with UTSI, look at shadowgraph data during an experiment in SL-2, a sea level turbine engine test cell at Arnold Air Force Base, Tenn., to study flow visualization for preemptive acoustic abatement in turbine test cells. (U.S. Air Force photo by Jill Pickett) (This image has been altered by obscuring badges for security purposes.)