Successes and Challenges in Computational Aerodynamics

The purpose of this paper is to survey some of the highlights of computational fluid dynamics as an emerging branch of aeronautical science, and to identify several remaining unsurmounted challenges. Prior to the advent of the computer there was already in place a rather comprehensive mathematical formulation of fluid mechanics. This had been developed by elegant mathetical analysis, frequently guided by brilliant insights. Well known examples include the airfoil theory of Kutta and Joukowski, Prandtl's wing and boundary layer theories, von Karman's analysis of the vortex street, and more recently Jones' slender wing theory [I], and Hayes' theory of linearized supersonic flow [ Z ] . These methods required simplifying assumptions of various kinds, and could not be used to make quantitative predictions of complex flows dominated by nonlinear effects. The computer opens up new possibilities for attacking these problems by direct calculation of solutions to more complete mathematical models.