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The present paper deals with the accretion of supercooled large droplets (SLD) at high velocity on wall. A visualization technique of the accretion of ice is used to measure and characterize the thickness of ice during the accretion phenomenon. Influences of air velocity, air temperature, drop size, impact angle and altitude were studied. The experiments are conducted in the ONERA icing wind tunnel, which allows to reach regimes close to realistic conditions for aircrafts (i.e. high velocity: → 190 m/s and altitude: → 11 500 m).

The Phylog project aims at offering a model-based software-aided certification framework for aeronautical systems based on multi/many-core architectures. Certifying such platforms will entail fulfilling the high level objectives of the MCP-CRI / CAST-32A position paper. Among those, two types of analysis are required: interference and safety analyses. Because of the large size of the platforms and their complexity, those analyses can lead to combinatorial explosion and to some misinterpretation. To tackle these issues, we explore a service-based modelling approach that leads to a simplification of the analyses and to the highlighting of salient properties, making the adaptation of the certification argumentation efficient.

Numerical tools for 3D in-flight icing simulations are not straightforward to automate when seeking robustness and quality of the results. Difficulties arise from the geometry and mesh updates which need to be treated with care to avoid folding of the geometry, negative volumes or poor mesh quality. This paper aims at solving the mesh update issue by avoiding the re-meshing of the iced geometry. An immersed boundary method (here, penalization) is applied to a 2D ice accretion suite for multi-step icing simulations. The suggested approach starts from a standard body-fitted mesh, thus keeping the same solution for the first icing layer. Then, instead of updating the mesh, a penalization method is applied including: the detection of the immersed boundary, the penalization of the volume solvers to impose the boundary condition and the extraction of the surface data from the field solution.

This paper proposes an experimental investigation of fast impinging large droplets in non-icing conditions. Two main aspects of the impact event are analyzed and discussed: the impact dynamics as a function of the surface nature and the deposition rate of the liquid on the impingement surface for various conditions. The data has been recorded and characterized at ambient pressure and a temperature of the air between 5 and 10°C using a vertical wind/droplet tunnel. To avoid the droplets evaporation the relative humidity was controlled. The morphology of impact was studied by backlighted imagery and quantitative results were obtained by image analysis. The deposition rate was obtained weighting the water accumulated on the impingement plate. Examination of splashing events images obtained on a clean surface and on blotter paper shows important differences in terms of secondary drop generation.

Critical control systems are often built as a combination of a control core with safety mechanisms allowing to recover from failures. For example a PID controller used with triplicated inputs. Typically those systems would be designed at the model level in a synchronous language like Lustre or Simulink, and their code automatically generated from those models. In previous SAE symposium, we addressed the formal analysis of such systems - focusing on the safety parts - using a combination of formal techniques, ie. k-induction and abstract interpretation. The approach developed here extends the analysis of the system to the control core. We present a new analysis framework combining the analysis of open-loop stable controller with those safety constructs. We introduce the basic analysis approaches: abstract interpretation synthesizing quadratic invariants and backward analysis based on quantifier elimination.

Avionics systems distributed on AFDX networks are subject to stringent real-time constraints that require the system designer to have techniques and tools to guarantee the worst case traversal time of the network (WCTT) and thus ensure a correct global real-time behavior of the distributed applications/functions. The network calculus is an active research area based on the (min,+) algebra, that has been developed to compute such guaranteed bounds. There already exists several academics implementations but no up to date industrial implementation. To address this need, the PEGASE project gathers academics and industrial partners to provide a high quality, efficient and safe tool for the design of avionic networks using worst case performance guarantees. The PEGASE software is an up-to-date software in the sense that it integrates the latest results of the theories, in tight cooperation with academics researchers.

Model Based Safety techniques have been developed for a number of years, though the models have not been customised to help address the safety considerations/ actions at each refinement level. The work performed in the MISSA Project looked at defining the content of “safety models” for each of the refinement levels. A modelling approach has been defined that provides support for the initial functional hazard analysis, then for the systems architectural definition level and finally for the systems implementation level. The Aircraft functional model is used to apportion qualitative and quantitative requirements, the systems architectural level is used to perform a preliminary systems safety analysis to demonstrate that a system architecture can satisfy qualitative and quantitative requirements.

Within the European Integrated Project NACRE (New Aircraft Concept REsearch) led by Airbus, a team of research centers and universities developed a multidisciplinary flying testbed called IEP (Innovative Evaluation Platform). Under the form of a dynamically scaled model of a future civil transport aircraft, its role is to assist engineers during the assessment of flight dynamics characteristics and noise reduction capabilities. After the feasibility study during which potential scientific and economical benefits of such new test facility have been identified, the team decided to design and manufacture the IEP. Because of the dual aspect of the system (it is a flying unmanned aerial vehicle and a test facility), an extensive requirement analysis has been carried out by the partners in order to identify the necessary operational modes and their associated navigation and control strategies.

Recent aircraft incidents and accidents have highlighted the existence of icing cloud characteristics beyond the actual certification envelope defined by the JAR/FAR Appendix C, which accounts for an icing envelope comprising water droplets up to a diameter of 50 μm. The main concern is the presence of SLD (Supercooled Large Droplets), with droplet diameters well beyond 50 microns. In a previous European-funded project, EURICE, in-flight icing conditions and theoretical studies were performed to demonstrate the existence of SLD and to help characterize SLD clouds. Within the EXTICE project the problem of SLD simulation is addressed with both numerical and experimental tools is being addressed. In this paper the objectives and main achievements of the EXTICE project will be described.

The main purpose of the experiments described here is the analysis of the mechanisms of radome protection with lightning diverters of various types and sizes. A high voltage arrangement and associated diagnostics have been implemented to perform a quantitative study of the inception and propagation mechanisms of the corona and leader discharges that precede the final breakdown. It is shown that ambient humidity plays a significant role on the discharge process and that the nature of the discharge initiated from the strip is very different depending on the strip type. Segmented strips are more likely to allow energetic discharges to propagate from an internal antenna leading to radome puncture.

This paper describes the new analysis software for the contamination modelling and outgassing / vent analysis, which has been developed under ESTEC contract by HTS and ONERA. A major part of the software enhancements have been dedicated to the improvement of the algorithms describing the physical processes involved in outgassing and contamination of species in orbit conditions. However, this paper concentrates on additional aspects of the new software tool, which are of interest for space environment analysis software development in general and the thermal analysis community in particular: The use of commercial software packages for the generation of the discrete model geometry and result visualisation. The interfacing possibilities of the software tool with thermal analysis tools.

This paper presents a work carried out within the FULMEN lightning-on-aircraft oriented European project. It is the second part of the general presentation on the analysis of EM environment inside the aircraft. Therefore, it focuses on numerical calculations of voltage and current transfer functions on the ports of the same prototype wiring harness installed in several aircraft structures. The calculations have been carried out with the cable network CRIPTE code and rely on 3D field calculations performed by Ericsson Saab Avionics. The link between the cable code and the 3D code is achieved through the component of the incident electric field tangent to the running path of the wiring.

This paper describes the microaccelerometer ASTRE, developed as Laboratory Support Equipment of Columbus, to monitor the residual microgravity disturbance level in the very low frequency range. ASTRE will be integrated in the already flown Microgravity Measurement Assembly (MMA). The paper recalls the microgravity environment which is required on-board Columbus and shortly describes expected discrepancies between the requirements and the predicted, more noisy, situation.