Objectives and content
The present and future design of European aircraft is
characterised by ever increasing size and performance.
Large weight saving requirements are met by the introduction of new materials, leading to more flexible aircraft structures, with the associated aero elastic phenomena having a significant effect on the aircraft performance. Hence, the ability to estimate reliable margins for aero elastic instabilities (flutter,buffeting) is a major concern to the aircraft designer.
Therefore, aircraft industry urgently needs are improved set of robust, accurate and reliable prediction methods in the coupled aeroelastic, flight mechanics and loads disciplines. In particular, it is necessary to develop/improve and calibrate the numerical tools in order to predict complex aeroelastic phenomena, including both aerodynamic and structural non-linearities, with a high level of accuracy.
In this respect, the UNSI project is going to increase the capabilities of the European aeronautics industry in the area of aircraft design by enhancing the ability to accurately predict fluid-structure interaction phenomena.
The project couples efforts on Computational Fluid Dynamics (CFD) with Computational Structural Mechanics (CSM) in an interdisciplinary manner.
On the CSM side, complex structural models are available which are coupled with simple, linearised aerodynamics models to computationally clear a new design from flutter. However, to account for complex, non-linear flows, such as flows with separating boundary layers and/or unsteady shock movement, more sophisticated and more accurate CFD tools are required.
The treatment of complex unsteady flow phenomena demand
CFD tools with good predictive accuracy. Therefore, it proves necessary to overcome still existing problems in CFD, related to turbulence modelling for unsteady -timeaccurate - flows, highly flexible mesh movement and adaptation algorithms as well as to sophisticated coupling strategies. In order to support work on CFD improvement, comprehensive measurements of unsteady 2D and 3D flows are necessary, providing reliable results for global flow field variables as well as for boundary layer and turbulence quantities. These experimental results are seen to be an absolute must for a proper calibration work with the incentive of a direct crossfertilisation between experiment and computation.
Four major goals will be considered:
Improvements of computational fluid dynamics (CFD) methods with respect to time-accurate unsteady flow behaviour
A comprehensive calibration of CFD methods by caring out measurements and computations in parallel to realise cross-fertilisation and to improve turbulence modelling aspects particularly for unsteady flows.
Extension and/or development of coupling procedures to
account for sophisticated flow analysis tools (up to NavierStokes methods) coupled to structural mechanics.
Demonstration of the capabilities of the improved methods to predict unsteady aeroelastic phenomena for complex flow behaviour such as flow with separation and/or flutter.
Funding SchemeCSC - Cost-sharing contracts
PR4 1AX Preston
92552 Saint Cloud
161 11 Bromma
581 88 Linköping
GU14 0LX Farnborough - Hampshire
M60 1QD Manchester