“…In the second (present) period, not only has the instrumentation vastly improved, but the facilities are now more extensive. For example, aero-optical testing has now been performed at subsonic speeds at the Arnold Engineering and Development Center (AEDC; Hugo et al 1997, Fitzgerald & Jumper 2002 and in the SARL and TGF wind tunnels at the Wright-Patterson Air Force Base (Vukasinovic et al 2008(Vukasinovic et al , 2011Smith et al 2014a;Wittich et al 2014). Testing has also been performed at sub-, trans-, and supersonic speeds at the Air Force Academy (Gordeyev et al 2007a(Gordeyev et al ,b, 2012(Gordeyev et al , 2014b(Gordeyev et al , 2015bSiegel et al 2009;Nguyen et al 2015); at sub-, trans-, and supersonic speeds at the University of Notre Dame (Rennie et al 2008;Ponder et al 2010;Porter et al 2013b,c;Gordeyev et al 2014bGordeyev et al , 2015aHoupt et al 2016); and at hypersonic speeds at Purdue University (Gordeyev & Juliano 2016a,b).…”