Leading-edge roughness effects on the flow separation onset of the AVT-183 diamond wing configuration

Experimental investigations on a 53° leading-edge sweep diamond wing configuration with rounded leading-edge contour as part of the NATO Science and Technology Organization (STO) task group AVT-183 (Applied Vehicle Technology panel) are presented. The results obtained in a low speed wind tunnel facility include aerodynamic forces and moments and steady surface pressures. Special emphasis is laid on the effects of different leading-edge roughness, which is applied in the experimental analyses to ensure turbulent boundary layer characteristics on the entire diamond wing surface. The results show that the flow separation onset and the emerging leading-edge vortex are very sensitive to the roughness height applied to the diamond wing leading-edge. Both reasonably-tripped and over-tripped cases are obtained compared to the free transition case, which is discussed in detail. Moreover, comprehensive analyses on both the short term and the long term repeatability of the related cases are presented. Based on this analysis, one specific leadingedge roughness is defined as the target flow case, which provides the baseline for the flow field investigations and general CFD validation within the task group AVT-183.