SUBLIME (Supporting Understanding of Boundary Layer Ingestion Model Experiment) The introduction of engines integrated with the rear fuselage (BLI engines) in large passenger aircrafts poses new challenges regarding accurate experimental assessment of their performance, especially in terms of power savings, over conventional propulsive architectures (e.g. podded engines) as the engine is fed with a distorted flow. The SUBLIME project will address this challenge, resulting in a flexible and robust experimental set-up to establish dependencies among the propulsor shape/position, the fan inlet distortion pattern and the corresponding power savings. A consortium of an R&D institute, an SME, and 2 Universities with complementary skills will produce this result in close coordination with the topic manager in 36 months, asking for a grant of € 3.612.500. Coordinator ARA will provide a number of aircraft configurations equipped with BLI propulsors integrated in the rear fuselage, designed and optimized in cooperation with HIT09 (mainly responsible for CFD studies and fan design), Cranfield University (mainly responsible for theoretical and experimental force bookkeeping) and Chalmers University of Technology (mainly involved in engine cycle studies), to be subsequently manufactured and tested by ARA in their transonic wind tunnel. The project will advance the state of the art in BLI studies by means of wind tunnel activities supported by high-fidelity CFD simulations to consistently predict full-scale behaviour of the aircraft architectures suitable for appropriate propulsor installation which minimizes inlet flow distortions and maximizes power saving. The results of installed wind-tunnel tested aircraft+propulsors will be delivered in full compliance with the call. SUBLIME will provide methodologies, tools and facilities to the European aviation industry, therefore contributing to releasing the full potential of power saving of BLI engines.

Ultra-high bypass ratio engines offer propulsive efficiency improvements and potential fuel burn reduction. The associated larger diameter can lead to an increase in nacelle drag that can erode the expected cycle benefits. Also, larger engines are likely to be closely coupled with the aircraft. Consequently, compact nacelles are needed to counter these aspects and to translate cycle fuel burn benefits into combined engine-airframe performance. An objective of ODIN is to develop design capability and detailed aerodynamic knowledge for installed compact nacelles to operate at off-design conditions such as take-off high lift, windmill and idle. Within a wider context of future power-plant integration, ODIN’s objectives include the improved understanding of exhaust suppression and jet-flap interaction noise. The viable design space for compact nacelles will be determined, across cruise and off-design conditions, with a multi-objective, multi-point optimisation method. High fidelity computations, and state-of-the-art high-resolution measurements with a novel section test rig, will reveal detailed aerodynamics of the design-limiting flow separation mechanisms. A synthesis of the multi-fidelity computational and experimental data will provide a calibration of the medium fidelity methods required for industrial design. An advanced dual-stream exhaust rig test will quantify installed exhaust suppression and jet-flap interaction noise and provide unique data to calibrate the computational methods at design and off-design conditions. Design constraints imposed by noise levels will be identified through experiments and high fidelity acoustic computations, which will also propose acoustic sensor layouts for the UHBR flight test demonstrator. Overall, ODIN will deliver validated design guidelines for novel nacelles to ensure cruise and off-design performance as well as the validation of computational methods for jet noise and exhaust suppression modelling.

A number of active and passive Loads Control and Alleviation concepts and technologies will be proposed, developed and evaluated. Aerodynamic design of an innovative spoiler will be undertaken, followed by a detailed aerodynamic characterisation of the spoiler and aileron capability for active loads control alleviation, conducted by means of CFD simulations and Wind Tunnel Tests. Novel passive loads alleviation concepts, such as passively morphing aerofoils using thickness and stiffness tailored skins or memory polymer skins and passively floating flaps, are going to be investigated and evaluated. A structural concept for an aeroelastic winglet for passive loads alleviation in manoeuvres and gusts will be developed.