Development of a Multi-Processor Unstructured Panel Code coupled with a CVC Free Wake Model for Advanced Analyses of Rotorcrafts and Tiltrotors

The accurate aerodynamic modeling of full-aircraft configurations is a challenging and significant issue for every rotorcraft manufacturer company. The unsteady aerodynamic interaction between rotating wings, their trailed wakes and fixed airframes, normally affects rotor performance, handling qualities, acoustic emission and vibratory levels in several ways. For better understanding these problems and improving helicopters and tiltrotors design procedure, the Aerodynamic Dept. of AgustaWestland Company has started the development of an advanced high-sophisticated aerodynamic panel code (ADPANEL) with the main idea to realize an useful and accured numerical tool that could provide high-fidelity predictions of rotor performance, interactional aerodynamics and noise, as well as the possibility to handle with full rotorcraft and tiltrotor configurations, with computational times and costs that were orders of magnitude less than CFD methods. ADPANEL is a Full-Unstructured Panel code implementing the most advanced aerodynamic features in the field of potential methods, such as the possibility to represent the surfaces in unstructured-hybrid meshes, for a Constant Vorticity Contour (CVC) modeling of both rotary and fixed wing wakes, and for its Multi-Processor implementation. In this paper the unsteady formulation of the ADPANEL flow-solver will be presented together with numerous examples of its validation, by using different sets of experimental data based on a wide range of helicopter and tiltrotor applications.