STRUCTURAL INSTABILITY OF INVISCID TRANSONIC CHANNEL FLOWA. V. Ivanova UDC 533.6.011 Transonic flow past a step located on the lower wall of a channel and modeling the airfoil is considered. The stability of stationary flow to small changes in the Mach number at the outlet of the channel is investigated numerically. The existence of special regimes in which flow is unstable, i.e., insignificant perturbations of the boundary conditions cause a qualitative change in its structure, has been established. A. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15 P. Brovka Str., Minsk, 220072, Belarus. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 76, No. 6, pp. 58-60, November-December, 2003. Original article submitted February 25, 2003.