Abstract : This study is an experimental investigation of a swirling inner flow which develops along a constant-diameter centerbody in the presence of an unconfined, axially-directed outer flow. The data which have been acquired include local mean velocity and static pressure profiles at six streamwise locations for different prescribed mass flow rate ratios. Local wall shear stress measurements were made at these six streamwise locations in order to investigate local law-of-the-wall behavior in the vicinity of the centerbody. Reynolds stress measurements were also made in order to quantify the local turbulence structure. This report describes the scope of these measurements and the physical characteristics of the flow which have been deduced from the data. The implications of the results from a turbulence modeling point of view is also discussed. (kr)