Experimental investigations on vortex flow phenomena of a diamond wing configuration

A 55° leading-edge sweep diamond wing configuration named SAGITTA is studied experimentally at low speed conditions with different measurement techniques. Wind tunnel results of aerodynamic forces and moments and steady surface pressure measurements as well as flow field characteristics gathered from Stereo Particle Image Velocimetry are presented. Because of spanwise varying leading-edge contours, different regions of separated flow occur on the diamond wing configuration with increasing angle of attack. Due to the 12% relative thickness airfoil, vortex formation only takes place at the sharp inboard leading-edge segment. In the wing tip area, in contrast, where rounded leading-edge contours are present, the emerging separation region is dominated by irregular flow with flow reversal. For the angle of attack of a = 16°, the resulting flow field is discussed in detail with regard to overall aerodynamic characteristics, mean velocity distributions and turbulent flow field quantities. The trajectory of the inboard vortex and the structure of the wing tip separation area are thereby analyzed.