AVT-183 diamond wing flow field characteristics Part 1: Varying leading-edge roughness and the effects on flow separation onset

Experimental investigations on a 53° leading-edge sweep diamond wing configuration with rounded leading-edge contour are presented. The analyses pertain to recent work that was conducted within the NATO Science and Technology Organization (STO) task group AVT-183 (Applied Vehicle Technology panel). The results were obtained in a low-speed wind tunnel facility and include aerodynamic forces and moments, and time-averaged surface pressures. Special emphasis is placed on the effects of different surface roughness, which was applied in the experimental analyses at the wing leading edge to fix turbulent boundary-layer characteristics. The results show that the flow separation onset and the emerging leading-edge vortex are very sensitive to the roughness height and any leading-edge contour modification. Compared to the free transition case, both reasonably-tripped and over-tripped cases are obtained, which is discussed in detail. Moreover, measurement repeatability issues are reviewed from a short-term and a long-term perspective. As an outcome, one specific leading-edge roughness is selected for the target flow conditions, which provided the baseline for subsequent flow field investigations and general CFD validation within the task group AVT-183.