On the use of Taylor's hypothesis in constructing long structures in wall-bounded turbulent flow

Abstract

Taylor's hypothesis of frozen flow has frequently been used to convert temporal experimental measurements into a spatial domain. This technique has led to the 'discovery' of long meandering structures in the log-region of a turbulent boundary layer. There is some contention over whether Taylor's approximation is valid over large distances. This paper presents an experiment that compares velocity fields constructed using Taylor's approximation with those obtained from particle image velocimetry (PIV), i.e. true spatial data. It was found that Taylor's approximation was largely valid over the spatial range (≈δ) of the PIV images.