Investigation of vortex structures on delta wings

Results of experimental and computational investigations of the flow around delta wings with both round and sharp leading edges are presented. The experiments were carried out in the low speed- and the supersonic wind tunnel of the Aerodynamisches Institut of the RWTH Aachen. The laser-light-sheet technique together with smoke injection was used to visualize the details of the vortex structures developing, with increasing angle of attack, on the leeward side of two different delta wings : the ELAC I and a configuration with the same planform, but a sharp leading edge. The results indicate clearly the influence of the nose radius on the vortex formation. These investigations were completed by oilflow patterns. In the numerical simulation a solution of the parabolized Navier-Stokes equations was constructed with a space marching technique for three-dimensional supersonic flow. The computations were carried out for a freestream Mach-number M∞ = 2. The computed vortex structures exhibit a remarkable similarity to those observed in the low speed experiments.