Advanced rotorcraft aeromechanics studies in the French-German SHANEL project

Abstract

The present paper gives an overview of the SHANEL research project (partly supported by the French DGAC and the German BMWA) which was started at the end of 2006 between the German and French Aerospace Research Centres DLR and ONERA, the University of Stuttgart and the two national helicopter manufacturers, Eurocopter and Eurocopter Germany. This program represents the continuation of the binational CHANCE project, involving the same partners. The objective of the project is to enhance and further validate the CFD tools: the structured multi-block elsA software of Onera and the unstructured TAU code of DLR, for computing the aerodynamics of the complete trimmed helicopter, accounting for the blade elasticity by coupling with blade dynamics and structural mechanics tools. A coupling activity between the FLOWer code of DLR and the HOST tool of Eurocopter is also completed to achieve the free flight trim of a complete helicopter. In this program particular attention is being given to wake conservation, to the modelling of elaborated complex shapes such as rotor hubs and consequently to interactional phenomena, with the global objective of improving the prediction of helicopter performance and noise. Rotorcraft noise prediction chains were rationalized, enhanced and compared. The validation activity of the flow solvers elsA and TAU is progressing from the CHANCE results and is now focussing on more complex problems such as the simulation of a rotating rotor head mounted on its fuselage, of a complete helicopter in steady mode through the use of actuator discs and engine boundary conditions, the time-accurate simulation of a complete trimmed helicopter in forward-flight, and the numerical simulation of Blade Vortex Interactions. All along the research program the updated versions of the CFD and acoustic codes are systematically delivered to industry. This approach, also followed during the former CHANCE project, is chosen to speed up the transfer of capabilities to industry and check early enough that the products meet the expectations for applicability in the industrial environment of Eurocopter.