Previous projects
Several past projects involving electroacoustic absorbers paved the way for INTSURFACE, both inside and outside FEMTO-ST. Some of them are:
SALUTE - Smart Acoustic Lining for UHBR Technologies Engines
Innovative acoustic liner technology for the aerospace sector
Designers of new aircraft engines aim to reduce noise emissions to maximise efficiency and increase the competitiveness of the aerospace sector. Ultra-high bypass ratio engine technologies represent significant challenges for the design of acoustic treatments. These turbofan engines are expected to equip the next generation of aircraft leading to lower frequencies than existing engine technologies. The EU-funded SALUTE project will apply an innovative approach by developing a new acoustic liner technology based on arrays of small loudspeakers or passive membranes. The technology will deliver excellent sound absorption at low frequencies while remaining sufficiently small to adjust to thin nacelle geometries.
https://cordis.europa.eu/project/id/821093/fr
https://archiveweb.epfl.ch/salute-h2020.epfl.ch/index.html
SmartAnswer - Smart mitigation of flow-induced acoustic radiation and transmission for reduced aircraft, surface transport, workplaces and wind energy noise
A step change in our noise mitigation strategies is required in order to meet the environmental targets set for a number of sectors of activity affecting people through noise exposure. Besides being a hindrance to our daily life and subject to regulations, noise emission is also a competitive issue in today’s global market. To address these issues, new technologies have been emerging recently, based on radically new concepts for flow and acoustic control, such as micro-electro-mechanical devices (MEMs), meta-materials, porous treatment of airframe surfaces, airfoil leading-edge or trailing-edge serrations, micro-jets, plasma actuation, … Some of these new ideas appear nowadays promising, but it now appears to this consortium that the development and maturation of novel noise reduction technologies is hindered by three main factors. The first factor is an insufficient understanding of the physical mechanisms responsible for the alteration of the flow or acoustic fields. In absence of a phenomenological understanding, modelling and optimization can hardly be successful. Secondly, tight constraints (safety, robustness, weight, maintainability, etc.) are imposed to any novel noise mitigation strategy trying to make its way to the full-scale industrial application. Thirdly, there is an insufficient knowledge about the possibilities that are nowadays offered by new materials and new manufacturing processes. With this project, we intend to setup a research and training platform, focused on innovative flow and noise control approaches, addressing the above shortcomings. It has the following objectives: i) fostering a training-through-research network of young researchers, who will investigate promising emerging technologies and will be trained with the inter-disciplinary skills required in an innovation process, and ii) bringing in a coordinated research environment industrial stakeholders from the aeronautical, automotive, wind turbine and cooling/ventilation sectors.
https://cordis.europa.eu/project/id/722401
ENOVAL - Engine Module Validators
ENOVAL is a EU-funded project aiming at developping novel aircraft engines architectures (geared and ungeared) achieving breakthrough performances in terms of environmental pollution (carbon dioxyde emission efficiency, noise reduction). A direction towards CO2 reduction lies in shortening the engine nacelle, thus leaving less space for acoustic lining (conventional sound absorbers). In that frame, the development of surface acoustic absorbers concepts with subwavelength dimensions was targeted. In this project, EPFL was a subcontractor of the French nacelle manufacturer AIRCELLE, and collaborates with FEMTO-ST (Besançon, France) to develop novel acoustic liners concepts with distributed active acoustic impedance control features. The technology is based on the Electroacoustic Absorber concept developped at EPFL, combined with distributed acoustic impedance control strategies developped at FEMTO-ST.