JAI Associates, Inc. proposes to develop an innovative hybrid computational fluid dynamics (CFD) method for accurately calculating aerodynamics and aeroacoustics of V-22 configuration. In particular, the complex downloads problem will be addressed in the Phase I research effort. A multi-block Navier- Stokes numerical method that is capable of resolving the flowfield by using Chimera overset grids will be used. An accurate turbulence model will be utilized to capture the massively separated flowfield associated with the downloads problem. A rotating Kirchhoff formulation will be coupled to the flow solver. The Navier-Stokes upwind scheme called TURNS, developed by the Principal Investigator, will be the heart of the proposed numerical scheme. This method has been demonstrated to be accurate, robust, and computationally efficient. Phase I effort is a 6-month study to obtain a demonstration calculation of the downloads for a V-22 tilt rotor configuration in hovering flight. A successful demonstration of this will provide a solid foundation for realistic calculations on a full V-22 tilt rotor aircraft in hover and axial flight in Phase II research. The individual items to be completed for the success of Phase I research are 1) identification and gridding of a V-22 rotor and wing using several body-conforming overset grids; 2) implementation of Chimera or Pegasus schemes in to the Navier- Stokes upwind numerical code; 3) a demonstration calculation of V-22 tilt rotor downloads; 4) implement rotating Kirchhoff formulation for calculating farfield noise accurately will begin in Phase I; and 5) compare results with experiments and prepare a final report. Phase II and the follow-on efforts will provide additional man-years to complete the task generated by Phase I and proposed for Phase II. JAI Associates, Inc. personnel and the proposed consultant are uniquely qualified to undertake this work since they are recognized leaders in the field of rotorcraft research. Commercial applications include the design of advanced technology tilt rotors for better aerodynamic and aeroacoustic performance. The method could also be used for designing efficient rotor blades for helicopters and tilt rotors. Other important applications include the interaction of multiple moving bodies relative to each other such as the main rotor and tail rotor of helicopter, tandem rotors, turbines and compressors in engines, and store separation etc.
Keywords: Phase_I, NASA, Abstract, FY94
