Experimental investigation on jets released from an orifice in the wall of a pressurized pipe

Turbulent jets discharged through an orifice embedded in the wall of a pressurized pipe are encountered in several environmental and engineering applications, including marine wastewater disposal systems, mixing devices, and leakage phenomena in water distribution networks. Despite their practical relevance, the scalar transport properties of these flows remain poorly understood, due to the complex interaction between the emerging jet and the internal pipe crossflow. The present work investigates the dilution characteristics of non-buoyant turbulent jets released from a sharp-edged circular orifice by means of planar Laser-Induced Fluorescence (LIF) measurements. An experimental campaign was conducted by varying the flow-rate ratio between the jet and the pipe flow, while maintaining a constant Reynolds number of the internal stream. Mean concentration reduction fields, normalized concentration variance distributions, and Coefficient of Variation maps were analyzed to characterize both the average and fluctuating components of scalar transport.