• 한국항공우주학회지
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• 제33권7호
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• pp.18-25
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• 2005

본 연구에서는 뒷전, 전단류와 초기교란의 상호작용에 의한 불안정파의 생성 기제의 분석과 뒷전 산란현상을 고차의 전산공력음향학을 이용하여 모사하였다. 수치적 알고리즘은 Hybrid 기법에 기초하였으며, Simple Linearized Euler Equation과 Full Linearized Euler Equation의 결과를 비교를 통해 정상류 구배항이 불안정파의 생성에 중요한 역할을 함을 볼 수 있었다. 또한 Full Navier-Stokes Equation을 이용한 결과와 비교함으로써, Full Linearized Euler Equation은 뒷전의 초기 근접장에서 불안정파를 해석하는데 있어서 Full Navier-Stokes Equation 보다 효율적임을 알 수 있다.

• International Journal of Aeronautical and Space Sciences
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• 제18권2호
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• pp.197-205
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• 2017

We investigate the slat noise generation mechanism by using large-eddy simulation (LES) and simple source modeling based on linearized Euler equations. An incompressible LES of an MD 30P30N three-element airfoil in the high-lift configuration is conducted at $Re_c=1.7{\times}10^6$. Using the total derivative of the hydrodynamic pressure (DP/Dt) acquired from the incompressible LES, representative noise sources in the slat cove region are characterized in terms of simple sources such as frequency-specific monopoles and dipoles. Acoustic radiation around the 30P30N multi-element airfoil is effectively computed using the Brinkman penalization method incorporated with the linearized Euler equation. The directivity pattern of $p^{\prime}_{rms}$ at $r=20c_{slat}$ in the multiple sources is closely compared to that obtained by the application of the LES/Ffowcs-Williams and Hawking's methods to the entire flow field. The power spectrum of p' at ${\theta}=290^{\circ}$ is in good agreement with the data reported in BANC-III, especially the broadband part of the spectrum with a decaying slope ${\propto}f^{-3}$.