As new fuel-efficient bypass engines are becoming increasingly wider in diameter, the distance between the (underwing mounted) engine and runway decreases. Reduced ground clearance can boost ground interactions during taxi and take-off phases, and ground vortices can appear, especially when there are crosswinds.These ground vortices go into the engine intake and can damage fan blades due to foreign object ingestion, dynamic loading and structural vibration. It is therefore crucial to be able to predict the characteristics of these ground vortices during early design phase, to improve engine's fan blades for safety and performance issues.
During early design phases, only reduced instrumentation can be used, whereas in-depth measurements would be required for ground vortex characterization. Therefore, InVIGO project's main objective is to build a predictive model to be used during early design phases with such reduced instrumentation. This model will use machine learning algorithms that will be trained with database coming from wind tunnel testings and numerical simulations performed within Invigo. Both reduced and detailed measurements will be carried out to build the training database. This main objective is therefore related to two essential steps. First is carrying out two wind tunnel campaigns in CSTB facility with a engine nacelle model and many instruments (pressure probes and rakes, Stereo-PIV, PTV, ...). Second is performing a hundred of numerical simulations (CFD) to complement wind tunnel measurements and addressing topics that cannot be dealt with experimentally (scale effect for example).
At the end of the project, the conclusions are the following. All the technical objectives were reached. A large number of simulation and wind tunnel tests were carried out and generated a very large database. Many predictive model were built and trained and the best one gave good results regarding the prediction of average vortex characteristics. This model was embedded within an interface to be reused on new vortex configurations. The impact of the project is also in line with what was planned at the beginning. Altran and CSTB presented 6 papers in scientific conferences and there is one paper published in a journal. The project outcomes will help in achieving Clean Sky 2 objectives regarding pollution, safety and costs, thanks to new engines more optimized. The EU competitiveness will also rise thanks to the new capabilities of the Jules Verne wind tunnel of CSTB, which also gained key expertise on such European projects. In parallel, Altran reinforced its expertise in simulation and data science and its ability to coordinate and manage such consortium. Last but not the least, the Topic Leader will eventually use all the content generated to best design the next generation of engine, whether classical ducted engines such as the UHBR, or newer technologies such as the unducted RISE project. Discussions and common actions are planned far beyond the end of the project between all takeholders.
