Modes of Turbulent Vortex Shedding from a Pipe-Jet System in a Cross-Flow

Results are presented of extensive measurements of a unified pipe-jet system in which no plate is used in the plane of the pipe orifice. It is found that the pipe and the jet shed vortices at significantly different rates. The differences depend on the ratio of jet speed to undisturbed-crossflow speed. Measurement made over the full of the z-coordinate from pipe base to jet locations at which shedding disappears, and over a wide range of the above ratio, revealed that four different modes can be defined, each mode overlapping the z-adjacent mode. The jet and pipe modes occur distinctly for values of the cited ratio greater than 5. Characteristics of the observed four modes are given.