基于多源特征融合神经网络的机翼气动噪声预测

Straight wing aerodynamic noise prediction based on multi-source feature fusion neural networks

  • 摘要: 为实现基于流场特征的机翼气动噪声预测,本文以安装柔性锯齿状仿生覆羽的NACA0018型平直机翼为研究对象,使用热线风速仪、PIV和远场麦克风在风洞实验中测量机翼尾缘的速度场和远场噪声数据。针对来流风速、覆羽厚度、安装位置等工况特征和典型尾流速度场特征,本文构建了早期融合神经网络(early-fusion neural network, EFNN)与后期融合神经网络(late-fusion neural network, LFNN)两种深度神经网络架构,并对比二者对远场噪声的预测精度。在无物理约束的条件下,两模型均能较好地复现频谱的总体变化趋势,其中EFNN的预测精度略高于LFNN。引入总声压级(overall sound pressure level, OASPL)物理约束损失项后,LFNN在提高OASPL预测精度的同时,相比EFNN保留了更高的1/3倍频程声压级预测精度。此外,SHAP特征归因分析表明,两种架构学到的流场-噪声映射关系基本一致,雷诺数是主导预测的关键特征,验证了模型预测的物理合理性。

     

    Abstract: To achieve flow-field-based prediction of airfoil aerodynamic noise, this study investigates a straight NACA0018 wing equipped with artificial flexible serrated coverts, a bio-inspired trailing-edge treatment intended to attenuate aerodynamic noise. The wake velocity field near the trailing edge and the far-field noise were measured in wind-tunnel experiments using hot-wire anemometry, particle image velocimetry (PIV), and far-field microphones. Because trailing-edge noise is governed by both the near-wake turbulence structure and the global flow condition, features from complementary measurement techniques were combined to provide a more complete physical description of the noise-generation mechanism. Using case features (freestream velocity, covert thickness, and mounting position) together with characteristic wake velocity-field features as inputs, two deep neural network architectures, an early-fusion neural network (EFNN) and a late-fusion neural network (LFNN), were developed and compared in terms of their far-field noise prediction accuracy. The prediction target was the one-third-octave-band sound pressure level. Without a physical constraint, both architectures reproduced the overall trend of the noise spectra well, with EFNN achieving slightly higher accuracy than LFNN. After introducing an overall sound pressure level (OASPL) physical-constraint loss term, LFNN improved the OASPL prediction accuracy while retaining higher one-third-octave-band sound pressure level accuracy than EFNN. Furthermore, a SHAP-based feature-attribution analysis showed that the flow-field-to-noise mappings learned by the two architectures were largely consistent, with the Reynolds number identified as the dominant predictive feature, confirming the physical plausibility of the model predictions and pointing to a data-driven route for rapid aerodynamic noise estimation.

     

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