Plane Turbulent Jet Flow in a Favourable Pressure Gradient

SUMMARY An experimental study has been made of an incompressible turbulent plane jet exhausting downstream into an external flow having a favourable longitudinal pressure gradient approximating that of two-dimensional sink flow. Four flows were studied, for which the ratios of mainstream and jet velocities at the exit plane of the jet were in the range from 0.1 to 0.5. For each case velocity profiles were measured at four streamwise stations and a traverse was made along the jet centre line. The mean velocity profiles are shown to have the same shape as previously reported profiles for jets in a uniform stream. The stream-wise development of the width of the jet and the velocity on its centre line are presented nondimensionally and values of the lateral shear stress gradient, z , aY are evaluated on the jet centre line to give some indication of the development of the turbulence structure.