The objective of this research was to study the effect of various Lagrange-
tracking correlation methods in estimating the eddy lifetime for a two-stre
am, turbulent, planar free shear layer. Zeroth-, first- and second-order La
grange correlation methods were applied to the time-evolving velocity field
data collected from a cinematic particle image velocimetry technique. A ti
me scale associated with the eddy lifetime was obtained based on a 2/e corr
elation of either vorticity or streamwise velocity fluctuations. When based
on vorticity, this time scale significantly increased as expected when the
tracking was computed with a second-order Lagrangian tracking technique as
compared to a (zeroth-order) Taylor hypothesis approach. However when base
d on streamwise velocity fluctuations, this time scale did not increase sig
nificantly for the higher order projection methods. The latter result is at
tributed to occurrences of "reverse correlation" of the instantaneous strea
mwise velocity fluctuations caused by eddy rotation.