Numerical drag prediction of NASA common research models using different turbulence models

This paper describes the results of 3D turbulent flow simulations to predict the drag of Wing-Body-Tail (WBT) and Wing-Body-Nacelle-Pylon (WBNP) aircraft configurations from NASA Common Research Models. These configurations were part of the 4th and 6th AIAA Drag Prediction Workshops in which CFD modelers participated worldwide. The computations are performed using CFD solver ANSYS FLUENT. The compressible Reynolds-Averaged Navier-Stokes (RANS) equations are solved using two turbulence models – the Spalart-Allmaras (SA) and SST k-ω. Drag polar and drag rise curves are obtained by performing computations at different angles of attack at a constant Mach number. Pressure distributions and flow separation analysis are presented at different angles of attack. Comparisons of computational results for WBT and WBNP models are made with the experimental data using the two turbulence models; good agreements are obtained. For WBNP, an aero-elastically deformed model of the wing is also considered at an angle of attack of 2.75°; the computations again are in reasonable agreement with the experiment. The computed WBNP results are compared with WB results for the drag increment study.