A TWO-DIMENSIONAL REPRESENTATION OF THE CROSSWIND FOR THE JET INTERFERENCE PROBLEM.
GEORGIA INST OF TECH ATLANTA SCHOOL OF AEROSPACE ENGINEERING
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The problem of a jet exhausting normally from an infinite flat plate into a crosswind is studied analytically, primarily in terms of the resulting interference pressures on the plate. Three jet exit shapes are considered a circle an ellipse with the major axis aligned with the crosswind streamwise exist and an ellipse with the major axis perpendicular to the crosswind blunt exit. It is shown that a two-dimensional steady potential flow model for the crosswind in planes parallel to the plate may be used, provided the jet-to-crosswind speed ratio is sufficiently large and the wake region is excluded. A blockage-sink model is developed wherein the blockage elements represent blockage due to the jet plume and due to the presence of the wake and a single sink represents entrainment. The model parameters are presented as functions of speed ratio and jet exist thickness ratio. The blockage and entrainment parameters are varied over a range of values to determine the effects of each on the interference pressure, and it is found that the entrainment factor is quite significant. The streamwise and circular jet exits are more useful for lifting-jet applications than the blunt exit because of their favorable coupling of the blockage and entrainment effects and their relatively small wake production. Author
- Fluid Mechanics