Two-Dimensional Unstructured Navier-Stokes Simulation of Multi-Element Airfoils Using Spalart-Allmaras One-Equation Model

A high-lift system is a crucial part of aircraft design because it influences takeoff and landing performance. Computational fluid dynamics as well as wind tunnel test has been recently incorporated into high-lift design and a multi-element airfoil is used to optimize high-lift performance. To estimate the high-lift aerodynamics of multi-element airfoils, two-dimensional compressible unstructured Navier-Stokes code with Spalart-Allmaras one-equation turbulence model is presented. For this validation, subsonic flows over a two-element configuration, NASA Model-B airfoil, and a three-element configuration, RAE 2815 airfoil, are computed. On surface pressure coefficient distributions and boundary-layer velocity profiles, the present computed results show good agreement with the wind-tunnel testing data. Also performed are the computations of subsonic flows over a five-element configuration, NASA Model-D airfoil, to demonstrate the possibility for more complex geometry. The present code is expected to be powerful tool for high-lift design.