The fountain flow created by two underexpanded axisymmetric, turbulent jetsimpinging on a ground plane was studied through the use of laser-basedexperimental techniques. Velocity and turbulence data were acquired in the jetand fountain flow regions using laser doppler velocimetry and particle imagevelocimetry. Profiles of mean and rms velocities along the jet centreline arepresented for nozzle pressure ratios of two, three and four. The unsteady natureof the fountain flow was examined and the presence of large-scale coherentstructures identified. A spectral analysis of the fountain flow data wasperformed using the Welch method. The results have relevance to ongoing studiesof the fountain flow using large eddy simulation techniques.
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