Vortex development on the AVT-183 diamond wing configuration - numerical and experimental findings

Within the NATO Science and Technology Organization (STO), the task group AVT-183 focuses on the “Reliable Prediction of Flow Separation Onset and Progression for Air and Sea Vehicles”. In this context, a 53° leading-edge sweep diamond wing configuration with blunt leading-edge contour is considered. At low speed wind tunnel (W/T) conditions, the separation onset of the emerging leading-edge vortex is studied in detail. In numerous experimental investigations, an extensive data base has been set up, which is to be used for general CFD validation of this kind of flow separation problem. In the combined numerical and experimental study of the present publication, three different CFD analyses are compared to each other and are opposed to the available experimental results. Both the surface flow and the flow field characteristics are regarded. From the W/T investigations, global force and moment data are available as well as surface pressure data and flow field measurements (Stereo Particle Image Velocimetry PIV) in defined chord-wise sections. The CFD analyses are based on Unsteady Reynolds-Averaged Navier-Stokes ((U)RANS) equations and differ in mesh strategy, turbulence model and the CFD solver applied. In the numerical results shown in this paper, differences in the flow separation onset are noticed. Based on the underlying flow physics, these differences are discussed in detail. In addition, the downstream progression of the vortex separation is considered. Based on the location of the onset, the bursting behavior of the leading-edge vortex in the rear sections of the wing is considerably influenced. With the analysis and comparison of different flow field characteristics in several chord-wise sections, the discussion is furthermore deepened. The flow separation onset and progression of the AVT-183 diamond wing configuration are discussed in detail.