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Transonic hovering rotor aero-acoustic predictions using Navier-Stokes/Kirchhoff method |
Received:December 06, 2007 |
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DOI:10.7511/jslx20096013 |
KeyWord:rotor hover navier-stokes equations kirchhoff formulism chimera grid aero-acoustics |
Author | Institution |
刘金花 |
特灵空调系统中国有限公司,上海 |
徐丽 |
上海电力学院数理系,上海 |
杨爱明 |
复旦大学 力学与工程科学系,上海 |
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Abstract: |
An numerical method based on chimera techniques was developed to compute the far-field acoustic signature of a helicopter rotor in hover. The numerical simulation was carried out in two parts of flowfeild simulation and acoustic prediction. The aerodynamic field was evaluated by solving equations on a system of overset grids——a NS solver based upon an efficient rotor mesh to simulate the viscous flow and vortex wakes near the rotor blades, a Euler solver based upon a cylindrical back mesh which was conformed with the nature topology of rotor hovering problem and was far from the viscous area to capture far-field wake. Computed flowfield information was interpolated onto a Kirchhoff integration surface. The far-field noise can be computed by integrating pressure data of cells of the Kirchhoff surface that completely encloses the rotor blades. The sound propagation to the far field was computed with Kirchhoff formalism. This paper focused on studying the influence of choosing Kirchhoff surface including top and bottom or not and considering the flow solution of rotor mesh or not on the result of noise prediction. As a demonstration of the overall prediction scheme, only using the integration surface with top and bottom and considering simultaneously the flow solution of rotor mesh, the computed result of far-field noise for high-speed impulsive case showed the best agreement with experimental data. |