一种高效精确的MTE-MART算法用于时间分辨层析PIV测量和分析

The motion-tracking-enhanced MART (MTEMART;
Novara et al. in Meas Sci Technol 21:035401,
2010) has demonstrated the potential to increase the accuracy
of tomographic PIV by the combined use of a short
sequence of non-simultaneous recordings. A clear bottleneck
of the MTE-MART technique has been its computational
cost. For large datasets comprising time-resolved
sequences, MTE-MART becomes unaffordable and has
been barely applied even for the analysis of densely seeded
tomographic PIV datasets. A novel implementation is
proposed for tomographic PIV image sequences, which
strongly reduces the computational burden of MTE-MART,
possibly below that of regular MART. The method is a
sequential algorithm that produces a time-marching estimation
of the object intensity field based on an enhanced
guess, which is built upon the object reconstructed at the
previous time instant. As the method becomes effective
after a number of snapshots (typically 5–10), the sequential
MTE-MART (SMTE) is most suited for time-resolved
sequences. The computational cost reduction due to SMTE
simply stems from the fewer MART iterations required
for each time instant. Moreover, the method yields superior
reconstruction quality and higher velocity field measurement
precision when compared with both MART and
MTE-MART. The working principle is assessed in terms
of computational effort, reconstruction quality and velocity
field accuracy with both synthetic time-resolved tomographic
images of a turbulent boundary layer and two
experimental databases documented in the literature. The
first is the time-resolved data of flow past an airfoil trailing

edge used in the study of Novara and Scarano (Exp Fluids
52:1027–1041, 2012); the second is a swirling jet in a water
flow. In both cases, the effective elimination of ghost particles
is demonstrated in number and intensity within a short
temporal transient of 5–10 frames, depending on the seeding
density. The increased value of the velocity space–time
correlation coefficient demonstrates the increased velocity
field accuracy of SMTE compared with MART.