Advection velocities of flow structures estimated from particle image velocimetry measurements in a pipe

摘要

Measurements with particle image velocimetry of a fully developed turbulent flow of water in a pipe with a Reynolds number of 5,370 are presented. The measurements are taken with a frame rate high enough to capture the same flow structure in two or three successive frames. It is thus possible to estimate the advection velocities of the flow structures. Ejection and sweep structures are identified and it is found that the average advection velocities for the structures were 80% and 87% of the centerline velocity for ejections and sweeps, respectively. An alternative analysis based on linear stochastic estimation shows similar results. [References: 19]