Study of Cfd Variation on Transport Configurations from the Second Drag Prediction Workshop

This paper describes and analyzes a series of nearly CFD test cases performed as a contribu tion to the second Drag Prediction Workshop held in association with the AIAA in June Two con gurations are included DLR F wing body and wing body nacelle pylon The ability of CFD to pre dict the drag lift and pitching moment from exper iment including the delta arising from the ad dition of the nacelle and pylon is assessed In general at a xed angle of attack CFD overpre dicts lift but predicts the CL reasonably well At low lift levels CL CD is drag counts high At the target lift coe cient of CL CD is overpredicted by between counts However the primary contribution of this paper is not so much the assessment of CFD against experiment but rather a detailed assessment and analysis of CFD variation The series of test cases are designed to determine the sensitivity variability of CFD to a variety of factors including grid tur bulence model transition code and viscous model Using medium level grids million points at the target lift coe cient the maximum variation in drag due to di erent grids is drag counts due to code is counts due to turbulence model is counts due to transition is counts and due to viscous model is counts Other speci c variations are described in the paper