Use of semi-empirical models to predict jet noise radiated by unsuppressed and suppressed nozzles

ONERA is involved in two R&T projects related to supersonic aircraft : a self-funded project called PINSON in which a 10-passengers supersonic concept-plane is developed with an aim of reducing consumption, sonic boom and take-off noise, and EU-Project SENECA aiming at providing insights on i) achievable noise levels during takeoff and landing and ii) global climate impact of supersonic aircraft. In both project, the semi-empirical models developed by Stone et al. have been identified as valuable tools for predicting jet noise, which is assumed to be the main contributor to supersonic aircraft noise at take-off. With an aim of extending the work initiated by Jaron et al. in the SENECA framework, ONERA applied Stone et al.'s models to various jet configurations to better understand their domain of validity. Ultimately, the objective is to use those models during engine pre-sizing phase of PINSON project in which a low-noise nozzle equiped with chevrons will be optimized from a multidisciplinary point of view. The objectives of the paper are i) to present the results obtained by applying those models on the EXEJET configurations and ii) to discuss the ability of the latest version of the model to predict chevrons acoustic impact.