Electrification of vehicles and improved efficiency of internal combustion engines (ICE) are the main levers to reduce greenhouse gas emissions. Recent studies indicate that in 2040 thermal cars sales will still remain an important part of the market and the spark-ignition engine (SIE) is seen as the most interesting ICE technology. However, technological challenges must be tackled before meeting real driving emissions expectation due to the diversification and complexity of hybrid applications. For flow aerodynamics, mixing and combustion down to the individual engine cycle, challenges are for example associated to robustness of concepts on a cycle basis, rapid variations of engine loads observed in hybrid technologies during transients, the occurrence of extreme cycles for a wider range of operating conditions. Numerical, experimental and analyzing tools have made significant progress in recent years for the analysis of spatial and temporal scales of the unsteady in-cylinder flows. Large-Eddy Simulation (LES) is an essential tool for the design of robust concepts. While LES has been validated against well-defined experiments, the prediction of internal turbulent dynamics and combustion during a cycle is affected by epistemic uncertainties. Therefore, progress is still needed to obtain optimal and robust design. The main objective of ALEKCIA is to develop game-changing tools for augmented prediction and analysis of turbulent reactive flows with a focus on real SIE operations to better capture time-resolved events and increase understanding and control of the origins of undesired behaviors. The key hypothesis is that future progress and success is tied to the synergistic, strong combination of experimental and numerical tools at every stage of the project, which will provide advancement in the analysis of physical scales and boundary conditions (BCs). The major scientific challenges addressed by ALEKCIA are to 1/ quantify and reduce uncertainties (UQ) due to model parameters and BCs, 2/ develop new Data Assimilation (DA) approaches for coupling LES with experimental measurements, 3/ develop new decomposition methods to analyse big data generated by LES and high-speed PIV, 4/ combine them with UQ and DA methods for detailed analysis of individual SIE cycles during steady operations and fast transients. We stress that this methodology could also be used more widely for industry and energy applications. To achieve its ambitious objectives, work in ALEKCIA is structured into one management task (T0) and three technical tasks (T1 to T3). We will address non-cyclic phenomena under transient and fired operations and develop novel analysis from the acquired experimental and LES databases of a SIE performed respectively at PRISME (T1) and IFPEN (T3) laboratories. The partners of the project will also collaborate on the development of crank-angle resolved spatio-temporal EMD decomposition (T1 and T3) for engine flows to obtain an unprecedented detailed understanding of the mechanisms involved in the generation of in-cylinder flow, turbulent dynamics and their impact on combustion. The development of UQ tools to quantify and reduce uncertainties in complex LES of SIE flows is also targeted (T3). Finally, the capabilities of DA methods to calibrate realistic BCs on-the-fly is investigated by PPRIME (T2 and T3). This task is particularly relevant when assimilating experimental data (in the form of BC and in-cylinder large-scale flow patterns from EMD) obtained in extreme cycles. EMD obtained from a selected number of measured cycles presenting very slow or fast combustion rates will be coupled with UQ and DA tools for their inclusion in LES (T3). In this scenario, LES will be able to properly follow the assimilated aerodynamic behaviour of these cycles while turbulent dynamic will be modelled. Finally, the application of the developed tools will allow to identify the main key parameters controlling internal aerodynamics.

The political and societal orientations towards "clean" mobility and the dwindling oil reserves are leading to major changes in the transport and automotive sectors. Indeed, with the announced end of the sales of greenhouse gases emitting vehicles (diesel and gasoline) by 2025 to 2040 by many countries (The Netherlands, Norway, France, United Kingdom ...), it is becoming crucial for automotive manufacturers and suppliers to develop reliable solutions adapted to the new technologies for transport and mobility. It is in this context that COFIX Joint Laboratory is established: Platform for the research and development of fastening clamps subjected to thermomechanical and vibratory stresses. The latter is initiated between the Laboratory of Mechanics Gabriel Lamé (LaMé - EA 7494) under the authority of INSA Centre Val de Loire (Blois), and the company CAILLAU (Romorantin), 4th worldwide manufacturer of clamps and sealing for the automotive and aeronautics sectors. Indeed, it is crucial for CAILLAU to innovate in order to support the energy transition of vehicles, and to develop new products adapted to the specific specifications of these emerging markets. Thus, the company CAILLAU repeatedly called on the scientific expertise of the LaMé Laboratory in the field of strength of materials, structure calculations and vibration mechanics in the context of internships of engineering students, industrial missions and a doctoral thesis from 2005 to 2009. However, there has been no long-term project or research action between the two partners so far. The COFIX LabCom would thus allow to deepen and perpetuate the collaboration. In particular, the proposal of new concepts for clamps, the study of the behavior of clamps subjected to high temperature, and the development of new applications for clean mobility are envisaged. Notably, an innovative test bench will be implemented in order to consider the coupled impact of pressure-vibration-temperature stresses, and thus increase the reliability and tightness of the clamps. Furthermore, the development of numerical models (finite elements) will allow to generalize and assist the process of new products development. These experimental and numerical approaches will provide scientific results aiming to achieve the following innovation objectives: • Within 1 year: development of new clams adapted to the last generations of thermal engines • Within 2 to 3 years: development of new clamp concepts adapted to very high temperatures and allowing to reach the new pollution reduction requirements • Within 3-7 years: development of new clamp concepts adapted to clean mobility

Three-dimensional bluff-body wakes are of key importance due to their relevance to the automotive industry. Such wakes contribute to consumption and greenhouse gas emissions. Drastic European Union limitations concerning these two mechanisms conduct the car industry to think about efficient vehicles. In this project, we propose robust drag and fuel reduction solutions for road-vehicles by closed-loop control of turbulent flows working efficiently for a range of operating conditions including changing oncoming velocity and transient side winds. To achieve this goal, we combine passive, active control and closed-loop strategies by using compliant deflectors, unsteady micro-jets and Machine Learning techniques. This project aims to prove a feasibility of the control from laboratory scale up to a full-scale industrial demonstrator. The main repercussions of the project will be on the reduction of the environmental impacts of transport industry and the gain of competitiveness and employment. This project consists on experiments in wind and water tunnels, numerical simulations and control strategies. Two models will be used, the square back bluff body and a reduced scale car model. The latter is representative of SUV and is inspired from the model used in collaborative work between POAES and PRISME. Control strategies will be tested in both configurations by combining passive and active actuation i.e. fixed or moving flaps and micro jet actuators. Closed-loop control will also be developed in these situations. Control strategies will be mainly developed by PPRIME. Experiments will be done in PRISME and PPRIME. LHEEA will take in charge numerical simulations and optimization. Finally, PSA will provide the vision of an automobile manufacturer on the industrial feasibility of the developed control strategies.

The URBEX project aims at developing a validated, breakthrough, fast-running, meshless model for the propagation of blast waves in urban configurations, accounting for all urban effects: multiple reflections, diffractions, channeling in urban canyons and urban canopy bypassing. The project intends to fill the gap identified between empirical operational or normative approaches (circular danger zones) and the use of 3D numerical codes requiring specific expertise and significant computing resources. Its applications concern global security and industrial security, as well as more generally the protection of people and goods. The URB(EX)3 model will be able to compute a complex overpressure wave shape at any point in the zone of interest. Consequences on people and infrastructures will be computed using both regulatory overpressure thresholds and probabilistic consequence models from the literature. The model will be embedded in an existing user-friendly platform, DEMOCRITE, developed during the eponymous ANR project and already tested by several organizations. Model inversion will also be addressed for two applications: 1. Definition of a protection perimeter / a vehicle exclusion zone around a building or a user-defined zone for a given threat level; 2. Forensic analysis of the observed damage to estimate the likely equivalent explosive mass. This model will be supported by series of analytical, high-quality, small-scale experiments in order to: - Guide the fitting of model parameters, when necessary, - Investigate specific phenomena, for instance blast channeling in city streets, - Help quantifying model uncertainties and safety margins, - Test the model on more global configurations, - Prepare for further extensions (terrain effects, height-of-burst explosions…). The only assumptions are: - The explosion takes place at ground level, assuming hemispherical high-explosive shape, - Free-field functions for blast parameters as a function of reduced distance: P(Z), I+(Z) , etc. are supposed to be known for the explosive under study, - The urban configuration is given (for instance in the shapefile format) by a set of buildings, each of them described by its polygonal footprint and its height (this is the standard for the IGN BD TOPO® v3 database, and corresponds also to the CityGML level of detail 1 description), - The terrain is flat. However, some of these limiting assumptions (height of burst explosion, actual vs. simplified building façades, terrain slope, clearing effects…) will be questioned during the project through dedicated experiments and/or numerical simulations. Finally, the partners have collected letters of support from several organizations, which will be part of the project's advisory board: IRCGN, LCPP, EURENCO, IRSN and CETID. The objective is to ensure that the project meets the actual needs of various potential users.