Advanced Small Perturbation Potential Flow Theory for Unsteady Aerodynamic and Aeroelastic Analyses

An advanced small perturbation (ASP) potential flow theory has been developed to improve upon the classical transonic small perturbation (TSP) theories that have been used in various computer codes. These computer codes are typically used for unsteady aerodynamic and aeroelastic analyses in the nonlinear transonic flight regime. The codes exploit the simplicity of stationary Cartesian meshes, with the movement or deformation of the configuration under consideration incorporated into the solution algorithm through a surface boundary condition. The formulaic details of the ASP theory are described, and the improvements are demonstrated through careful comparisons with accurate alternative calculations. The new ASP potential flow theory, including entropy, vorticity, and viscous effects, is shown to be mathematically more appropriate and computationally more accurate than the classical TSP theories. Thus, the ASP theory has been used as the basis for a new computer code called Advanced Small Perturbation—3D (ASP3D), which is briefly described along with representative unsteady aerodynamic and aeroelastic results.