Performance and accuracy investigations of two Doppler global velocimetry systems applied in parallel

摘要: Two Doppler global velocimetry systems were applied in parallel to assess their performance wind tunnel environments. Both DGV mounted on a common traverse surrounding the glass- walled 1.4×1.8 m 2 test section of tunnel. The normally supports three-component forward-scatter laser system. reproducible vortical flow field generated by blunt tip an airfoil was chosen for this investigation and precisely surveyed LDA just prior measurements. shared same continuous wave light source, frequency stabilization fiber optic sheet delivery principle differences between implementations are with regard imaging configuration. One configuration relied single camera that observed three successively operated sheets. In second configuration, views simultaneously using four-branch bundle. bundle system had all view points forward scattering arrangement which increased efficiency but reduced shift sensitivity. Since observation components acquired onto image frame, acquisition times could be minimum. On other hand, triple − two sheets scatter one backscatter. Although separate images recorded succession, quality, spatial resolution signal-to-noise ratio superior Comparison data LDV measurements shows very good agreement within 1-2 m/s. remaining discrepancy has variety causes, some related resolving power (graininess, smoothing), exact localization receiver head respect scene, drift or background influences. extensive base available allows more detailed study influences each these factors.