Similarity Parameters and Their Sensitivity for Transonic Airframe Exhaust Nozzle Interactions

A qualitative description of the fluid mechanics of transonic airframe interaction with engine exhaust flows is formulated and used to derive the pertinent similarity parameters of the problem. The sensitivity of the flow field to these parameters is explored by computations and analysis of available data and leads to the conclusion that viscous parameters such as boundary layer momentum thickness, engine exit flow profiles and mass flux ratio have a pronounced effect on simulation capability. Based on the findings of the similarity and sensitivity studies, experiments are outlined for both continuous and blowdown facilities to investigate the role of viscous parameters more fully. (Author)