Far-field boundary conditions for transonic lifting solutions to the Euler equations

Far-field boundary conditions for the Euler equations are formulated and applied to transonic lifting flow over an airfoil in an unbounded domain. An expansion of the linearized small-disturbance equation in the far field is developed and the leading-order term, corresponding to a point vortex representation for the airfoil, is retained. A comprehensive evaluation across the Mach number range of the procedure's effectiveness in eliminating dependence of the numerical results on the boundary extent is presented. Extension of the method to three dimensions is also outlined.