Loose Structural Coupling of a Helicopter Airframe

This research paper addresses the challenge of helicopter vibrations, which have significant implications for passenger comfort, mission effectiveness, and structural integrity. The paper introduces a new tool to enhance the existing tool chain used at Airbus Helicopters. The tool integrates advanced computational structural dynamics (CSD) with computational fluid dynamics (CFD) to improve the prediction of the dynamic response of the airframe to unsteady loads. The proposed method couples well-established computational tools in a loose manner. Specifically, the coupling involves the comprehensive CAMRAD II code and the CFD solver FLOWer. The authors propose a novel method that distributes the airframe loads through an artificial node, allowing unsteady loads based on CFD predictions to be incorporated into the CAMRAD domain. Additionally, the elastic deformations predicted by CAMRAD can be integrated into the CFD domain, thereby enhancing the physical representation of the system within CFD simulations. Furthermore, any motion calculated by CAMRAD, including rigid body motions of the helicopter, can now be included in the CFD, enabling a more comprehensive analysis.