The sound of moving bodies

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Revolutionary physics-based design tools for quiet helicopters

This paper describes a revolutionary, fully-integrated approach for modeling the noise characteristics of maneuvering rotorcraft. The primary objective of this effort is the development of a physics-based software tool that enables the design of quiet rotors without performance penalties. This tool shall accurately predict the rotorcraft flight state and rotor trim, the unsteady aerodynamic loading, the time-dependent flow field around the rotor blades, and the radiated noise, in all flight conditions including maneuver. This objective is achieved through the use of advanced computational fluid dynamics (CFD), computational structural dynamics (CSD), and computational aeroacoustics (CAA). The predictions are validated and verified against benchmark test cases. The advanced CFD methods include innovations in Large Eddy Simulation, novel techniques for flexible deforming blades, high-order methods for accuracy, and adaptive grids to accurately capture important flow features. CSD methods are coupled with the CFD and acoustics codes using generic interfaces. The aeroacoustic predictions build on an advanced method with enhancements for maneuvering flight