2C2D-PIV Measurements of a Turbulent Square Duct Flow at Reynolds Numbers up to 42 000

The turbulent flow was studied in small-scale gas-aerosol test facility using a particle image velocimetry (PIV) system. The experiments were conducted at Reynolds numbers Re = 8900, 27950 and 44250 in a square duct (d = 10 cm) without and with generic obstacles. The flow formation in the inlet was measured and documented without obstacles. It could be shown that the laws of a well developed turbulent boundary layer are applicable downstream of x = 15 d. Periodic steps (height H = 10 mm, channel width, pitch P = 100 mm) and cylindrical stumps (Ø 20 cm, H = 10 cm, P = 20 cm, square structure) were mounted on the bottom of the channel in order to study more complex flow phenomena. The time averaged mean flow field was illustrated at miscellaneous positions around the obstacles. It agrees well with published data. The showed results can be used for fundamental research on deposition and resuspension of aerosol particles.
The measurement uncertainty of the 2C2D-PIV-system tots up for about 4 percent of the measured value. The resolution of the vector field accounts between 0,4 and 0,8 mm.