Abstract
Lifetime of transient turbulence in a rectangular-duct with the cross-sectional aspect ratio A = 5 is measured experimentally by using a multi-PIV (Particle Image Velocimetry) system. The survival probability of transient turbulence is observed to decay exponentially as a function of its streamwise position. The comparison of the mean lifetime obtained from exponential fitting of the probability for A = 5 with the former experimental data for A = 3 shows that the mean lifetime significantly depends on the aspect ratio. For a fixed value of the bulk Reynolds number, the mean lifetime in the wider duct with A = 5 is shorter than that in the narrower duct with A = 3.
