The Effects of Ground Wall-Jet Characteristics on Fountain Upwash Flow Formation and Development

摘要

An experimental program was conducted to investigate the effects of ground wall jet characteristics on two-jet fountain upwash flow formation and development. Variations in wall jet properties were generated through parametric variations in nozzle pressure ratio and jet impingement angle. Hot film anemometer measurements of the wall jet and fountain upwash flow fields resulted in the determination of fountain upwash formation momentum recovery coefficients, fountain upwash inclination and spreading characteristics, and fountain upwash mass entrainment characteristics. The data obtained in this investigation provides empirical information required for an analytical model of fountain inclination developed during this study. This analytical model is compatible with a methodology and software for the prediction of multiple jet V/STOL aircraft ground surface flow fields previously developed for the Naval Air Development Center and later modified for the NASA Ames Research Center. (Author)