Geoscience Reference
In-Depth Information
Fig. 10 Response of polyamide seeding particles in a turbulent flow
Fig. 11 PIV measurements
require finding the initial and
final positions of particles
illuminated by two
consecutive laser pulses
within a given flow
subregion, called
interrogation area. This is
mostly achieved by cross-
correlation based algorithms
in that given interrogation area, relatively to orthogonal axes parallel to the sides,
are given by:
Þ'
ð
x
þ Dd
x
Þ
x
u
ð
x
;
z
Dt
(7)
Þ'
ð
z
þ Dd
z
Þ
z
w
ð
x
;
z
Dt
The key issue in the PIV data processing is determining the mean planar
displacements
Dd
x
and
Dd
z
in each interrogation area, with the smallest possible
error. The standard way to compute these mean displacements is based on cross-
correlation algorithms between the images resulting from two consecutive laser pulses.
