Rapid Computational Fluid Dynamics (CFD) Methodology for Rotorcraft Maneuver Analysis

The lack of proper estimation of air loads encountered during transient maneuvers introduces excessive design conservatism. A reduced fidelity CFD methodology based on momentum source (Rot3DC) and a comprehensive analysis code (RCAS) were coupled in Phase I to validate the ``proof-of-concept'' that such system is capable of rapidly analyzing steady and transient maneuvers. The tightly coupled system for an isolated rotor was shown to converge wherein the inflow was supplied by Rot3DC and the trim state was obtained from RCAS. In Phase II, the ``proof-of-concept'' will be extended to complete configurations with multiple rotors and fuselage. In addition to the kinematics of the rotor (trim) the structural deformations of the rotor blades will be fully included in the Phase II system. The rotor model in coupled Phase I analysis was restricted to translating discs. In Phase II, the momentum source model will be extended to unsteady rotors where individual blades will be recognized. The tool will be tested using candidate vehicles provided by the Army. Enhancements such as parallelization and complete design of a user interface will be investigated for implementation in Phase III.