Pitched and Yawed Circular Jets in Cross-Flow

Results from an experimental investigation of flow field generated by pitched and yawed jets discharging from a flat plate into a cross-flow are presented. The circular jet was pitched at α = 20° and 45° and yawed between β = 0° and 90° in increments of 15°. The measurements were performed with two X-wires providing all three components of velocity and turbulence intensity. These data were obtained at downstream locations of x = 3, 5, 10 and 20, where the distance x, normalized by the jet diameter, is measured from the center of the orifice. Data for all configurations were acquired at a momentum-flux ratio J = 8. Additionally, for selected angles and locations, surveys were conducted for J = 1.5, 4, and 20. As expected, the jet penetration is found to be higher at larger α. With increasing β the jet spreads more. The rate of reduction of peak streamwise vorticity, ω_xmax, with the downstream distance is significantly lessened at higher β but is found to be practically independent of α. Thus, at the farthest measurement station x = 20, ω_xmax is about five times larger for β = 75° compared to the levels at β = 0°. Streamwise velocity within the jet-vortex structure is found to depend on the parameter J. At J = 1.5 and 4, ‘wake-like’ velocity profiles are observed. In comparison, a ‘jet-like’ overshoot is present at higher J.