The spatial and temporal development of turbulent boundary layer flows is governed by the self-organization
of coherent structures like hairpin-like or arch vortices and spanwise alternating wall bounded low- and highspeed
streaks. For a detailed analysis of the topologies of the wall normal fluid exchange namely of the four
quadrants of the instantaneous Reynolds stresses Q1,,Q4 a 4D- measurement technique is desired.
In this feasibility study the tomographic PIV technique (Elsinga et al. 2005) has been applied to time resolved
PIV recordings. Four high speed CMOS cameras are imaging tracer particles which were illuminated in a
volume inside a boundary layer flow at 4 kHz by using two high repetitive Nd:YAG pulse lasers. The
instantaneously acquired single particle images of these cameras have been used for a three dimensional
tomographic reconstruction of the light intensity distribution of the particle images in a volume of voxels
(volume elements) virtually representing the measurement volume. Each of two subsequently acquired and
reconstructed particle image distributions are cross-correlated in small interrogation volumes using iterative
multi-grid schemes with volume-deformation in order to determine a time series of instantaneous 3D-3C
velocity vector fields. 自適應(yīng)粒子成像測速場儀(PIV) 德國LaVision PIV/PLIF粒子成像測速場儀 時間分辨粒子成像測速系統(tǒng)(TR-PIV) 體視層析粒子成像測速系統(tǒng)(Tomo-PIV)
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