The central goal of JERONIMO is the understanding of the physical mechanisms of ultrahigh bypass ratio (UHBR) engines with a bypass ratio (BPR) larger than 12 and the related installed jet noise with potential jet-wing interaction. The aim is to reduce uncertainties in jet noise characterisation of this novel installation configuration by wind tunnel tests and predictions and being able to derive design recommendation for future UHBR Engine jet noise reduction. For the achievement of those goals, UHBR engines have to be investigated experimentally for their jet noise characteristics in the isolated and installed configuration. A consistent database will be built at European level in the jet noise test facility at CEPRA19, applying advanced and improved measurement techniques such as far-field noise & near-field pressure measurements, combined with aerodynamic methods like PIV. In parallel, existing CFD-CAA simulation tools will be adapted and validated (or “used state-of-the-art” only), and the overall methodology to predict flight stream effects and complex interaction mechanisms for UHBR engine jet noise at medium and full scale will be developed. This will need an identification of the key physical or key flow features by a detailed processing of the experiments together with numerical data for steady and unsteady flow conditions and acoustics in combination with analytical/theoretical methods, such as flow instability analysis. Innovative nozzles will be designed regarding the UHBR architecture, tested and assessed to reduce UHBR engine installed jet noise. Finally, recommendations in term of e.g. the relative position of nozzle/wing will be provided, the methods & data will be assessed. An evaluation for aircraft noise and a common database will be established.