Abstract: When aerodynamic numerical simulation for flight vehicle and its components is conducted, the aerodynamic shape is generally given in the manner of discrete data. It is called an unsmooth surface if its first and second derivatives can't be both continuous and smooth. In order to resolve the problems caused by this phemomenon, the overall smoothing method based on x-axis transformationm, piecewise least-squares polynomial and least-squares cubic spline techniques and the local smoothing method based on weighting procedure are used to smooth the unsmooth surface. These methods improve the geometric characteristics of the aerodynamic shape first, and then improve the effect of the aerodynamic numerical simulation.

Key words: overall smoothing, local smoothing, numerical simulation, airfoil