Combined application of pressure sensitive paint and particle image velocimetry to the flow above a delta wing

What was learned from the new VFE-2 experiments

“…Unfortunately within VFE-2 not all details of the onset of vortical flow in the front part of the configuration could be investigated experimentally because of geometric constraints of the PIV setup in the wind tunnel, but due to the encouraging agreement between the experimental and the calculated results, further study of these details can be guided with analysis of numerical solutions. A series of pressure distributions for M = 0.4 and R mac = 3 million and for various angles of attack from the PSP measurements 15,19 at DLR Goettingen is shown in Fig. 9.…”

“…These experimental results are in excellent qualitative agreement with the numerical findings 16 as shown in the right-hand figure. The results of the two campaigns in the Transonic Wind Tunnel at Goettingen in 2004 and 2005 have been summarized 19 and they were also a subject of the 2006 AIAA achievements review 20 as well as to some VFE-2 status reports 21,22 .…”

What was Learned from the New VFE-2 Experiments?

“…A series of pressure distributions for M = 0.4 and R mac = 3 million and for various angles of attack from the PSP measurements 15,19 at DLR Goettingen is shown in Fig. 9.…”

“…Further downstream the outer vortex becomes the stronger one, whereas the inner vortex decays. These experimental results are in excellent qualitative agreement with the numerical findings 16 as shown in the right-hand figure. The results of the two campaigns in the Transonic Wind Tunnel at Goettingen in 2004 and 2005 have been summarized 19 and they were also a subject of the 2006 AIAA achievements review 20 as well as to some VFE-2 status reports 21,22 . The understanding of the onset of the vortical flow on the present delta wing with rounded leading edge can be summarized as follows: On the medium radius rounded leading edge VFE-2 configuration at " = 13° the first flow separation takes place in the front one-third of the wing, where the wing is relatively thick.…”

Experimental methods for multi-diagnostics of flow fields in wind tunnels

“…x/cr = 0.4. Instantaneous PIV results show (Konrath et al, 2006) that this vortex structure consists of several small co-rotating vortices spreading in the spanwise direction. The occurrence of the outer primary vortex leads to a vortex merging and a circular inner vortex is formed.…”