Mission statement

Enhancing test capability, quality and productivity of European wind tunnels of strategic importance.

Main goals

Disseminating knowledge about partner facilities and specific ESWIRP tasks.

Support of an internet networking service.

Concept and objectives

Ever since the start of aviation, in addition to flight testing, the need to have ground test facilities to understand flight physics phenomena and to investigate flight characteristics of future flying vehicles, has been recognized by flight physics researchers & aircraft designers. Today, within the aeronautical technology platform ACARE (Advisory Council for Aeronautical Research in Europe) it has been acknowledged that a set of world class and efficient research facilities is a strategic factor of significant importance for the prosperous development of aeronautics in Europe. The most commonly used types of ground test facilities for aviation by researchers and development engineers are wind tunnels. According to criteria set by ACARE the strategic facilities for Europe are the transonic wind tunnel ONERA S1MA, the low-speed wind tunnel DNW-LLF and the cryogenic wind tunnel ETW. Those wind tunnels are jointly responding to the targeted call formulated in the European Commission’s work program on Research Infrastructures, in particular the transport-related specific objectives (INFRA-2008-1.1.2.25).

A wind tunnel is a tool for simulating flight physics phenomena encountered when an aircraft moves in air. Typically, it uses scaled models of the projected aircraft under scrutiny. The very purpose of a wind tunnel is to contribute to the development of new aircraft by providing characteristic data at low technical & economical risks as compared to real flight testing.

Throughout all stages of aircraft development, from basic research of aerodynamic phenomena to applied research and optimisation of components and eventually validation of the end configuration, wind tunnel testing has always been an indispensable tool for researchers and designers. Although predictions of aircraft performance and characteristics through Computational Fluid Dynamics (CFD) calculations have been progressing tremendously, until now the development of an aircraft without wind tunnel testing has been unheard of because of risks and costs and will remain so for at least the next decades to come. Moreover, wind tunnel testing itself is an important contributing element to the ongoing development of sophisticated computational tools by validation and verification of numerical codes and data.

The demand for modern wind tunnel testing requires wind tunnels of excellent performance and quality and sophisticated aircraft models provided with up-to-date instruments and interference free flow measurement techniques, and above all, highly skilled personnel. Over the years, models, testing techniques and associated instrumentation have become more and more sophisticated in order to meet the ever increasing requirements of the aeronautic community in terms of accuracy and repeatability of results. Likewise, the skills necessary for wind tunnel testing and data analysis and interpretation require more and more qualified operation personnel and research staff.

Although strategic wind tunnels in Europe have been maintained in proper operating conditions, modernisation of testing techniques and upgrading of capabilities have suffered from lack of sufficient funding and have not shown as much progress as other elements of the testing chain like measurement techniques and data handling in terms of quality and productivity.

Accurate simulation of flight physics phenomena requires correct representation of the Mach number, i.e., the ratio of the flight velocity over the speed of sound, and (near) correct representation of the flight Reynolds number, i.e., the ratio of inertia forces over friction forces. In practise, this is realised by using either large models in atmospheric wind tunnels or with smaller models in a pressurised and/or cooled test environment. To achieve this either very large atmospheric wind tunnels such as the DNW-LLF and the ONERA-S1MA or pressurised cryogenic wind tunnels such as the ETW are required with comparatively large investment and operating costs. As a result, the aeronautic community, and primarily the research organisations responsible for operating these expensive wind tunnels are very cost-conscious and are forced to strive for high economic operational efficiency. Economic considerations also played an important role in the decision leading to the construction of the bi-national German-Dutch Wind Tunnel DNW-LLF in 1976 and the four-nation European Transonic Windtunnel ETW (France, Germany, the Netherlands, United Kingdom) in 1988, when national authorities decided it was no longer possible for one single country to face the huge capital and operating costs of such large facilities.

These trans-national co-operations happened in the context of a nascent restructuring of the European aeronautical industry, leading to the perception that there might be a structural overcapacity in wind tunnel testing in Europe, as a whole. This in turn led to the notion that rationalisation efforts were needed, first at national level, then at a larger European scale, in order to focus more closely on a limited number of critical facilities considered to be of strategic importance that should be maintained at top class level. Many efforts were made in the 90’s to rationalise the European wind tunnel inventory, although mostly at national levels. In 2004, at the initiative of the European Commission, an effort was started to think about further rationalization and integration of testing activities at community level by funding the European Windtunnel Association (EWA) Network of Excellence in which no less than 14 partners participate.

In this context, the ESWIRP project in response to EU 7FP Capacities-Research Infrastructures programme aims at enhancing aeronautical research in Europe by intensifying the cooperation between the three wind tunnels ONERA S1MA, DNW-LLF and ETW in a new Consortium.

Together these wind tunnels cover all the research needs for civil flight by complementing each other in terms of speed, size and simulation of flight conditions. The main ideas leading to the proposal are:

In order to meet these objectives the Consortium will optimise the use and development of the three strategic wind tunnels DNW-LLF, ONERA-S1MA and ETW by enhancing their potential and integrating their services. These wind tunnels are indeed research infrastructures of pan-European interest needed by the European scientific community to remain at the forefront of the advancement in aerospace research. The proposed integration will facilitate researchers to turn scientific ideas into technological innovations as aimed by the Lisbon strategy and will help industry strengthen its base of knowledge, technological know-how, and competitiveness. The total investment amount for these upgrades is estimated at 50 M€. Although ESWIRP will only cover a fraction (10 M€) of these costs it is expected that the funding of ESWIRP by the EC is a clear demonstration of European interest for preservation and upgrading of strategic facilities and will give the onset to a restructuring of the European wind tunnel infrastructure in the future for the benefit of European aeronautic research.

The activities planned under this project aim to optimise the utilisation of specific research infrastructures and to improve their performance. In recognition of the fact that existing world-class research infrastructures need huge and long-term investments in resources and should be used and exploited by an as large as possible community of scientists and customer industries on a European scale, the EC programme has defined the special instrument “Integrating Activities”.

ESWIRP responds to the so-called ‘targeted approach’ where the action is clearly beneficial to support strategic wind tunnels in the long term and follows the FP6 I3 (Integrated Infrastructures Initiatives) model, distinguishing between (i) Networking activities, (ii) Trans-national access and/or service activities, (iii) Joint research activities. The project will be conducted in close co-operation with the activities taking place under the sub-theme Aeronautics (within the theme Transport) to ensure that all the actions under this ESWIRP project indeed respond to the needs for wind tunnel testing within the relevant Co-operation programme projects (small and medium size co-operative projects, large co-operative projects or Clean Sky JTI).