The corrections for lift, drag, and moment of a two-dimensional air¬foil have been analyzed, on the assumption that the airfoil is tested in the working section of a supersonic tunnel in which the pressure field, instead of being uniform, is characterized by gradients in the axial and transverse directions. ΣnThe pressure gradients of the tunnel as well as the effect of the airfoil to be tested are regarded as perturbations of the original rec¬tilinear flow field of given Mach number. Therefore the velocity poten¬tial of the flow, the nonlinear differential equation of motion, and the boundary conditions are expanded into double series in powers of two parameters, one characterizing the airfoil thickness e and the other, the inhomogeneity of the field b. In this way the nonlinear problem is split into a system of linear boundary-value problems, corresponding to the different powers of b and ∈.
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