Swirl–nozzle interaction experiment: quasi-steady model-based analysis

Abstract Measurements of sound due to swirl–nozzle interaction are presented. In the experiment a swirl structure was generated by means unsteady tangential injection into steady swirl-free flow upstream from choked convergent–divergent nozzle. Ingestion nozzle caused mass-flow rate change, which resulted in downstream-measured acoustic response. The downstream pressure found remain negative as long is maintained and reflections open pipe termination do not interfere. amplitude this initial response be proportional square used generate swirl. When valve closed, through increased, resulting an increase pressure. This signal compared prediction empirical quasi-steady model, constructed steady-state measurements. As opening time varied, evacuation showed overshoot with respect behavior, after it gradually decayed behavior for times convection demonstrates that can obtain quantitative information concerning dependence system. could useful understanding dynamics engines swirl-stabilized combustion. Graphic abstract