In the 2nd AIAA CFD Drag Prediction Workshop  (DPW-2), the DLR
-F6 aircraft was utilised for estimating the capability in computing drag using different CFD tools. The DLR
-F6 model tests were done in the ONERA
S2MA wind-tunnel for Mach number 0.75 and Reynolds number based on the mean chord of 3x106. The boundary layer is tripped at a prescribed position. Interesting sensitivity for turbulence modelling was found for the wing-body-nacelle-pylon (WBNP) configuration at an angle of attach of 1.0 deg. corresponding to a lift coefficient of 0.5.
The most critical regions are identified to be close to the wing root and for the pylon-inboard section. The corner vortex related to the wind-body junction is developing in the stream-wise direction and evolves into a separated region. Also the junction between the wing and engine pylon induces a stream-wise vortex which is close to separation. Significant difference has been identified in the predictions of the flow separation by different models and, thus, discrepancies in the calculated aerodynamic quantities. Careful prediction of the aerodynamic forces as well as the ability to correctly predict the flow separation regions is the focus of this study with the primary aim of using RANS models.
There are two sets of grids available for this test case – block structured and unstructured grids with prismatic wall regions (hybrid). Both sets of grids were used at the 2nd drag prediction workshop, but have been further refined for this study. Three levels of grid are available for each set of grids with the finest grids with around 10 million grid points.
-  NASA 2nd Drag Prediction Workshop webpage: http://aaac.larc.nasa.gov/tsab/cfdlarc/aiaa-dpw/Workshop2/workshop2.html
-  Brodersen, O & Stürmer, A. 2001 Drag prediction of engine-airframe interference effects using unstructured Navier-Stokes calculations, AIAA 2001-2414.
-  Laflin, K. R., Vassberg, J. C., Wahls, R. A., Morrison, J. H., Brodersen, Rakowitz, M., Tinoco, E. N., and Godard, J., “Summary of Data from the Second AIAA CFD Drag Prediction Workshop,” Journal of Aircraft, Vol. 42, No. 5, 2005, pp. 1165–1178.
-  Pfeiffer, N. “Reflections on the Second Drag Prediction Workshop,” AIAA Paper 2004-0557