简介:Tomographic particle image velocimetry is a 3D PIV technique based
on the illumination, recording, reconstruction and analysis of tracer-particle motion
within a three-dimensional measurement volume. The recently devel简介:Tomographic particle image velocimetry is a 3D PIV technique based
on the illumination, recording, reconstruction and analysis of tracer-particle motion
within a three-dimensional measurement volume. The recently developed technique
makes use of several simultaneous views of the illuminated particles, typically 4, and
their three-dimensional reconstruction as a light-intensity distribution by means of
optical tomography. The reconstruction is performed with the MART algorithm
(multiplicative algebraic reconstruction technique), yielding a 3D distribution of
light intensity discretized over an array of voxels. The reconstructed tomogram
pair is then analyzed by means of 3D crosscorrelation with an iterative multigrid
volume-deformation technique, returning the three-component velocity vector distribution
over the measurement volume. The implementation of the tomographic
technique in time-resolved mode by means of high repetition rate PIV hardware
has the capability to yield 4D velocity information. The first part of the chapter describes
the operation principles and gives a detailed assessment of the tomographic
reconstruction algorithm performance based upon a computer-simulated experiment.
The second part of the chapter proposes four applications on two flow cases:
1. the transitional wake behind a circular cylinder; 2. the turbulent boundary layer
developing over a flat plate. For the first case, experiments in air at ReD = 2700
are described together with the experimental assessment of the tomographic reconstruction
accuracy. 详细>