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The highly-efficient and unsteady aerodynamic simulation of turbomachinery is urgently required. The panel-vortex particle method is coupled with a far free field sound model established with the Lowson method and aims to fast predict aerodynamic and acoustic properties. The aerodynamic results show that, compared with the aerodynamic results acquired with the finite volume method, the use of the panel-vortex particle method may obtain appropriate pressure distribution and velocity distribution in the downstream region of a propeller and that the overall thrust prediction is accurate enough. The vortex distribution features show that the panel-vortex particle method has less numerical diffusion. Therefore, the velocity gradient is more accurate near the wake vortex. Compared with the sound pressure level acquired with the finite volume method, the sound pressure level simulated with the panel-vortex particle method has the same directivity pattern. The relative error of sound pressure in the 60° forward direction is 5% under 1BPF(blade passing frequency), which satisfies acoustic analysis requirements. As for time consumption, the use of the panel-vortex particle method consumes 10% of time when the finite volume method is used, proving that the panel-vortex particle method coupled with the Lowson method can satisfy the design and application needs of unsteady aerodynamic and aeroacoustic noise of a distributed electric propulsion system.

The flapping-wing, inspired by natural flyers> is believed as a new conceptual flight technology with potential valuable applications. However, the unusual features of flappingwings, such as complex strong unsteady low Reynolds number aerodynamics and large number of design variables associated with both large flapping motion and shape geometries, pose great challenges for aerodynamic design/optimization. This paper discusses the development and application of unsteady aerodynamic optimization for flapping wing from the aspects of aerodynamic model, parameterization of design variables and optimizing strategies. The advances are reviewed in aerodynamic optimization techniques for flapping wing the traditional method the modern unsteady adjoint approach. Some remarks and speculations are given on the state-of-lheart of this research field. [ABSTRACT FROM AUTHOR]