Unsteady characteristics of inlet vortices

摘要: An experimental study of the unsteady characteristics inlet vortices has been conducted using a high-frame rate digital particle image velocimetry system. The results revealed formation pair counter-rotating for no-wind configuration and one single vortex when there was crosswind. In all measurement planes, from near ground to inlet, evidence meandering with quasi-periodicity found. meander is dominant in direction crosswind, its amplitude increases crosswind velocity. proper orthogonal decomposition analysis instantaneous velocity field suggested that most energetic mode helical displacement wave, corresponding first mode. Similarities trailing wings were noted. present also suggest focus separation formed on might be responsible nature vortex.