何嘉华, 王垿桁, 刘秋洪, 等. 可渗透面对流FW-H方程伪声产生机制和抑制方法[J]. 空气动力学学报, 2023, 41(6): 16−25. doi: 10.7638/kqdlxxb-2022.0103
引用本文: 何嘉华, 王垿桁, 刘秋洪, 等. 可渗透面对流FW-H方程伪声产生机制和抑制方法[J]. 空气动力学学报, 2023, 41(6): 16−25. doi: 10.7638/kqdlxxb-2022.0103
HE J H, WANG X H, LIU Q H, et al. Generation mechanism and suppression method of spurious sound from the permeable surface convective FW-H equation[J]. Acta Aerodynamica Sinica, 2023, 41(6): 16−25. doi: 10.7638/kqdlxxb-2022.0103
Citation: HE J H, WANG X H, LIU Q H, et al. Generation mechanism and suppression method of spurious sound from the permeable surface convective FW-H equation[J]. Acta Aerodynamica Sinica, 2023, 41(6): 16−25. doi: 10.7638/kqdlxxb-2022.0103

可渗透面对流FW-H方程伪声产生机制和抑制方法

Generation mechanism and suppression method of spurious sound from the permeable surface convective FW-H equation

  • 摘要: 可渗透面对流FW-H方程及其积分解在远场气动噪声预测中广泛应用,但当涡波通过可渗透面时会产生伪声传播。本文旨在清晰阐明这种伪声的产生机制,并提出有效抑制方法。耦合分析可渗透面对流FW-H方程的右端厚度源和载荷源,发现厚度源的物质导数和载荷源的散度操作可使积分面源自动过滤伪声源。伪声的产生源于对流FW-H方程的求解采用了Farassat提出的分部积分公式,因部分积分项被忽略,导致伪声源自动过滤功能失效。从厚度源和载荷源中抽取含有涡波扰动的项,在对流波动方程求解过程中保留相应的物质导数和散度操作,以抑制涡波伪声传播。数值测试算例验证了伪声产生机制和抑制方法的正确性。

     

    Abstract: The convective FW-H equation is widely used in far-field noise prediction. However, spurious noise arises when vortical waves pass through the unphysical permeable surface for integration purposes. This paper aims to clarify this spurious noise generation mechanism and to propose an effective suppressing method. By analyzing the thickness and the loading sources on the right-hand side of the convective FW-H equation, it is found that the material derivative operator in the thickness source and the divergence operator in the loading source enable the permeable surface sources to filter the spurious sources automatically. The spurious noise appears when solving the convective FW-H equation by the partial integral formulas derived by Farassat, which ignore some integral terms so that the automatic filtering of spurious sources in surface sources is disabled. The terms containing vortical waves are extracted from the thickness and loading sources, and the corresponding material derivative and divergence operators are retained while solving the convective wave equation to suppress the spurious noise propagation. Numerical tests are performed to validate spurious sound's generation mechanism and suppression method.

     

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