1. AS early as 1948, Callaghan and Ruggeri' examined a heated 200°C air jet directed normal t3 tine wind-tunnel flow. The heated jet exhausted into the confined tunnel through a sharpedged orifice. Jet velocities from approximately two to seven times the cross-stream velocity were inveStigated for penetration depth and mixing. Thermocouple and pitot tube rakes wePe util.ized well downstream of the jet inlet to record penetration depth and mixture temperatures. Ruggeri, Callaghan, and Bowden' extended this work in 1950 to include square and elliptical orifices.
2. In 1952, Ruggeri' extended his contribution to include various angles (30, 45, 60,and 90 degrees) Of injection. The angles required that a tube be utilized to inject the jet, as opposed to a Sharpedged Oririce. Ruggeri used Schlieren flow visualization to confirm his measurements and commented oh the wall effects of the wind tunnel.
3. Jordinson," 1958, was the first to determine experimentally the trajectory of the jet crosssection and defined the jet axis as the line connecting the points of maximum velocity. He also demonstrated tnat tne cross-section of an initially cylindrical jet is distorted into a 'horseshoe' shape by the cross-stream shearing action.
4. Keffer and Baines,", 1963, contributed Some very carefully measured Velocity data. More importantly, they studied the turbulent structure in the deflected jet and showed that similarity for a reasonably small range of velocity ratios (4, 6, and 8) could be shown. Their work was the first use Of a jet-oriented coordinate system, relating tne jet centerline to that of a free jet. Pratt and Baines'* refined this work to account for scatter in tie previous data, and also demonstrated tnat the profile of the jet is conserved as a mixture between Circular cross-Section Of random eddies and a pair of line vortices with small turbulences. Pratt and Keffer'' continued this investigation for various injection angles (60,75, 90, 115, and 135 degrees) to the main flow. Finding differences between tneir jet trajectories and that of Keffer and Baines". they recognized w the importance of the jet inlet velocity profile. In fact, their experiments used long tubular inlets whereas Keffer et a1 used a simple orifice inlet in the earlier study".
5. Some of the first work to examine multiple deflected jets is represented by Norgren and Humenik", 1968, intended to aid in tine design of short-length combustors. AS with the pioneering WOPk of Callaghan,' they restricted their investigation to penetration depth and degree of mixing for heated jets. It should be noted that this work was one of the first basic research studies into turbine inlet temperature profiles.