Fountain flows produced by multiple impinging jets in a crossflow

Abstract

A numerical and experimental study is made of the characteristics of vortex and upwash flows generated by multiple jets in a crossflow. Laser Doppler measurements and flow visualization are presented for turbulent circular jets emerging into a low-velocity cross stream and, then, impinging on a flat surface perpendicular to the geometrical jet nozzle axis. The experiments were performed for Reynolds numbers based on the jet exit conditions of 6 x 10 4 and 1.05 x 10 5 , a jet-to-crossflow velocity ratio of 30, and an impinging height of 5 jet diameters, and they include mean and turbulent velocity characteristics along the two normal directions parallel to the nozzle axis. This study provides a basis to understanding more complex practical flowfields, such as those in industrial environments where impinging jets compete on any crosswind and the flow created underneath a vertical/short takeoff and landing aircraft.