The final status of ESTRO activities, although not perfectly matching the original planned actions, can be considered satisfactory considering the difficulties faced by the consortium in terms of WT selection, late provision of the WT model and malfunctions of some of its components during the experimental campaign and considering the unavailability of some inputs necessary for the successful achievement of the project targets. Overall, 100% of the activities planned, revised and agreed with the PM were completed. The implemented mitigation actions, the constant interaction with PM and PO and the realignment of the activities according to the availability of data/inputs produced a positive impact with the consequent achievement of most of original objectives. Some targets could not be fully reached for the failure of the laminar-transition measurements during the WT campaign (due to a not appropriate surface preparation of the model not manufactured by ESTRO) and for the lack of a structural model of the wing for the FSI calculations. Nevertheless, once faced with the difficulties, the consortium reacted promptly, interacting with both PM and PO to recalibrate and realign the actions in relation to the achievable objectives, minimising the deviations from the original plan.
The identified solution for the WT provider, with the launch of the amendment to include DNW as new beneficiary and the realignment of the activities over 45 months, had a positive impact on the project, boosting the design and manufacturing process of the model (in charge to other consortia) and reducing risks associated with the model acceptance. The addition of the new beneficiary (DNW) to the project contributed to relieve some weakness of the initial proposal, mitigating the risks related to the launch of a European call for tender and including inside the consortium the specific knowhow necessary to design, optimise and perform an experimental campaign in a large WT facility. This positively contributed to solve several technical issues related to the functionality of the model and to the completion of the experimental campaign which was performed in the DNW LLF Wind Tunnel in December 2021 (figure 2). Numerical analysis and extrapolation of the experimental data added insights, increasing the output value of the project. In this respect, the approach chosen by ESTRO to perform the CFD campaign and the extrapolation of the experimental data to flight conditions proved its efficacy, identifying the possible reasons for the observed mismatch between the experimental and numerical data and providing a) a theoretical and quantitative explanation for the failure of the laminar-turbulent transition measurements b) a guideline on the quality of the surface finish level (in terms of surface imperfection characteristics) to achieve extended laminar flow in both WT and flight conditions, c) an extrapolation of the aerodynamic performance of the WT model to cruise conditions d) the evaluation of the robustness of CFD results with respect to the adopted turbulence model through an Uncertainty Quantification analysis (figure 3) e) a study of the effects of the Reynolds number on the extension of the laminar flow over the wing (figure 4) f) an estimation of the impact of the model deformation (figure 5) on the aerodynamic performance and g) an analysis of the detrimental effects of the propeller wake on the laminar flow extension in flight conditions (figure 6) .
The innovations and achievements of ESTRO were promoted through three main communication channels, that are: 1) the project website, 2) the participation to scientific congresses/workshops and the publication of scientific papers and 3) Consortium internal meetings. The website www.estro diin.unisa.it designed, hosted and maintained by UNISA, is available for public access, giving an overview of project objectives, significant results and main news and events. A detailed Plan for the Communications, Dissemination and Exploitation (PEDR) was designed and released by DREAM.
The spread of the Covid-19 pandemic and the compression of the efforts in the last months of the project led to a slowdown of the dissemination activities determining some changes to the original plan. Two conferences were attended (WCCM-ECCOMAS 2020 and 11th EASN Conference 2021) and two scientific papers published. The internal dissemination among the Consortium partners was guaranteed by bi-weekly informal meetings. In order to promote the dissemination and foster the collaboration of the different members of the consortium, seminars on advanced CFD techniques, were also organised at UNISA.
