A vertical round jet issuing into an unsteady crossflow consisting of a mean current and a sinusoidal fluctuating component

Abstract

We applied a CFD code to investigate the dispersion of a round jet issuing into an unsteady ambient crossflowing stream which consists of coherent sinusoidal fluctuations imposed upon an otherwise steady mean flow. The computed flow patterns were compared with our laboratory observations where we employed an alternative approach to simulate the fluctuating crossflow. Both sets of results showed that coherent oscillations in the ambient crossflow organized the jet fluids into successive large-scale clouds or patches and that the formation of the patches was regular. As a result, the mean dispersion of the jet was enhanced. However, the coherent fluid patches could lead to very high instantaneous concentration levels. The CFD results also served to support the validity of our experimental technique.