UNSTEADY EULER AIRFOIL SOLUTIONS USING UNSTRUCTURED DYNAMIC MESHES

Two algorithms for the solution of the time-dependent Euler equations are presented for unsteady aerodynamic analysis of oscillating airfoils. Both algorithms were developed for use on an unstructured grid made up of triangles. The first flow solver involves a Runge-Kutta time-stepping scheme with a finite-volume spatial discretization that reduces to central differencing on a rectangular mesh. The second flow solver involves a modified Euler time-integration scheme with an upwind-biased spatial discretization based on the flux-vector splitting of Van Leer. A significant aspect of the research is the implementation of a dynamic mesh algorithm that is employed for problems where the airfoil moves. Steady and unsteady results are presented for the NACA 0012 airfoil to demonstrate application of the Euler solvers and dynamic mesh algorithm. The unsteady flow results were obtained for the airfoil pitching harmonically about the quarter chord. The two sets of calculated instantaneous pressure distributions and lift and moment coefficients during a cycle of motion compare well with each other and with the experimental data. The paper presents descriptions of the Euler solvers and dynamic mesh algorithm along with results which assess the capability. © 1990 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.