Direct numerical simulations and models for hot burnt gases jet ignition

This work uses multiple three-dimensional Direct Numerical Simulations (DNSs) to i) investigate the ig- nition process of a cold lean premixed mixture at atmospheric conditions by a jet of hot burnt gases that may be cooled before injection ii) evaluate models able to predict the outcome of such a scenario in terms of ignition. Understanding and being able to model ignition of cold premixed mixtures by hot burnt gases is essential to design systems like engines (to ensure ignition) and flameproof enclosures (to prevent ignition). Limited work has focused on the combined effects of the jet injection speed and temperature on ignition. This is difficult to do by using experiments only and DNS is a natural approach to gain knowledge on that point. By varying the hot jet injection speed and temperature, the three- dimensional, kinetically detailed, DNSs allow a parametric study of the impact of these parameters on the ignition process and provide data to build and test models. Simulations prove that jet injection speed and temperature (usually less than the adiabatic flame temperature because of cooling effects through the injection hole) directly govern ignition. Chemical Explosive Mode Analysis (CEMA) is used to char- acterize the reacting flow structure which is strongly impacted by the jet injection speed. Based on the DNSs conclusions, a zero-dimensional Lagrangian model where a small element of the jet burnt gases mixes at a certain rate with the fresh gases while it potentially ignites is found to be a good candidate to predict the outcome of an ignition sequence (success or failure)

LoopJam: turning the dance floor into a

collaborative instrumental ma

Reactive Statistical Mapping: Towards the Sketching of Performative Control with Data

Part 1: Fundamental IssuesInternational audienceThis paper presents the results of our participation to the ninth eNTERFACE workshop on multimodal user interfaces. Our target for this workshop was to bring some technologies currently used in speech recognition and synthesis to a new level, i.e. being the core of a new HMM-based mapping system. The idea of statistical mapping has been investigated, more precisely how to use Gaussian Mixture Models and Hidden Markov Models for realtime and reactive generation of new trajectories from inputted labels and for realtime regression in a continuous-to-continuous use case. As a result, we have developed several proofs of concept, including an incremental speech synthesiser, a software for exploring stylistic spaces for gait and facial motion in realtime, a reactive audiovisual laughter and a prototype demonstrating the realtime reconstruction of lower body gait motion strictly from upper body motion, with conservation of the stylistic properties. This project has been the opportunity to formalise HMM-based mapping, integrate various of these innovations into the Mage library and explore the development of a realtime gesture recognition tool

Jet ignition prediction in a zero-dimensional pre-chamber engine model

This paper presents a multi-chamber, multi-zone engine model to predict the ignition of a lean main chamber by a pre- chamber. The two chambers are connected by small cylindrical holes: the flame is ignited in the pre-chamber, hot gases propagate through the holes and ignite the main chamber through Turbulent Jet Ignition (TJI). The model original fea- tures are: (i) separate balance equations for the pre- and main chambers, (ii) a specific model for temperature and com- position evolution in the holes and (iii) a DNS-based model to predict the ignition of the main chamber fresh gases by the burnt gases turbulent jets exiting the holes. Chemical reactions during TJI are the result of two competing mixing processes: (1) the hot jet gases mix with the fresh main chamber to produce heated zones and (2) at the same time, these hot gases cool down. (1) increases combustion and leads to ignition while (2) decreases it and can prevent ignition. The overall outcome (ignition or failure) is too complex to be modelled simply and the present model relies on recent DNSs of TJI which provided a method to predict the occurrence of ignition. Incorporating this DNS information into the engine model allows to predicts whether ignition will occur or not, an information which is not accessible otherwise using simple models. The resulting approach is tested on multiple cases to predict ignition limits for very lean cases, effects of H2 injection into the pre-chamber and optimum size for the holes connecting the two chambers as a function of equivalence ratio

VideoCycle: user-friendly navigation by similarity in video databases

Abstract. VideoCycle is a candidate application for this second Video Browser Showdown challenge. VideoCycle allows interactive intra-video and inter-shot navigation with dedicated gestural controllers. MediaCycle, the framework it is built upon, provides media organization by similarity, with a modular architecture enabling most of its workflow to be performed by plugins: feature extraction, clustering, segmentation, summarization, intra-media and inter-segment visualization. MediaCycle focuses on user experience with user interfaces that can be tailored to specific use cases. 1 The MediaCycle Framework The MediaCycle framework has been developed at the numediart Institute 1 of the University of Mons since 2008. Its scope is to provide tools to create applications for the navigation by content-based similarity into multimedia databases, currently audio, image, video, text, sensor signals and files. It focuses “by design” on fostering new artistic practices (the numediart Institute aims at improvin

Head pose estimation & TV Context: current technology

With the arrival of low-cost high quality cameras, implicit user behaviour tracking is easier and it becomes very interesting for viewer modelling and content personalization in a TV context. In this paper, we present a comparison between three common algorithms of automatic head direction extraction for a person watching TV in a realistic context. Those algorithms compute the different rotation angles of the head (pitch, roll, yaw) in a non-invasive and continuous way based on 2D and/or 3D features acquired with low cost cameras. These results are compared with a reference based on the Qualisys motion capture commercial system which is a robust marker-based tracking system. The performances of the different algorithms are compared function of different configurations. While our results show that full implicit behaviour tracking in real-life TV setups is still a challenge, with the arrival of next generation sensors (as the new Kinect one sensor), accurate TV personalization based on implicit behaviour is close to become a very interesting option

Large Eddy Simulation of Pre-Chamber Ignition in an Internal Combustion Engine

International audienceUsing homogeneous lean mixtures is an efficient way to reduce fuel consumption and pollutant emissions in internal combustion engines. However, lean combustion requires breakthrough technologies to induce reliable ignition and fast combustion. One of these technologies uses pre-chamber to create multiple hot turbulent jets and provide ignition sites for the lean mixture. In this paper, the behaviour of a pre-chamber ignition system used to ignite the main chamber of a real engine is studied using large eddy simulation with direct integration of analytically reduced chemistry using the dynamic thickened flame model. The large eddy simulation allows to analyze the flow entering and leaving the pre-chamber, to measure the cooling and quenching effects introduced by the hot gas passages through the ducts connecting pre-and main chambers and to analyze the ignition and combustion sequences. For the case studied here, small amount of flame kernels are exhausted from the pre-chamber. Hot products penetrate the main chamber, disperse and mix with the fresh reactants and lead to ignition. The combustion in the main chamber starts in a distributed reaction mode before reaching a flamelet propagation mode

MORFACE: FACE MORPHING

The purpose of this project was to produce a real-time installation which uses two approaches: a close approach dealing with user’s face and head position and a far approach where the installation reacts to user’s motion differently if it is repetitive or not. The installation was personalized by a Mona Lisa