从非定常流动，计算远场声音。From unsteady flow to far-field sound.
将气动声学方法转化为可使用的软件：基于 FW-H 方程预测非定常流动产生的声辐射。Turning aeroacoustic methods into usable software, with FW-H prediction of sound radiated by unsteady flows.
了解软件与使用入口Explore the software ↗01研究RESEARCH
于流动深处，探声音之源。 Within the flow, we seek the source of sound.
围绕低空飞行器与推进噪声，我们结合高保真计算、复杂流动机理与气动声学实验，研究声音的产生、传播和控制。We study low-altitude aircraft and propulsion noise through computational methods, complex-flow mechanisms and aeroacoustic experiments, examining how sound is generated, propagates and can be controlled.
研究方向RESEARCH DIRECTION
低空飞行器与推进噪声Low-altitude Aircraft & Propulsion Noise
研究螺旋桨、旋翼与低空飞行器在不同构型和飞行状态下如何产生并辐射噪声。结合流动与声学计算、消声环境测量，辨识桨叶几何、运动状态及机体散射对声音的影响，为低噪声设计和运行评估提供依据。We study how propellers, rotors and low-altitude aircraft generate and radiate sound across configurations and flight states. Flow and acoustic simulations, together with controlled measurements, help identify the effects of blade geometry, motion and airframe scattering on noise.
研究图像RESEARCH IMAGES
从图像观察流动与声场Flow and sound fields in images
精选论文SELECTED PUBLICATIONS
从论文了解这一方向Explore the work through selected papers
选取与本方向相关的近期成果；完整论文可在成果页面检索。Recent papers relevant to this direction. Find the full list under Publications.
- 2023Wu H, Chen W, Jiang H, Zhong S*, Zhang X*. Experimental investigation of the effect of sectional airfoil profile deviation on propeller noise. Physics of Fluids, 2023, 35: 027104. (Editor’s Pick) ↗
截面翼型轮廓偏差对螺旋桨噪声影响的实验研究Wu H, Chen W, Jiang H, Zhong S*, Zhang X*. Experimental investigation of the effect of sectional airfoil profile deviation on propeller noise. Physics of Fluids, 2023, 35: 027104. (Editor’s Pick)
Wu H, Chen W, Jiang H, Zhong S*, Zhang X*. Experimental investigation of the effect of sectional airfoil profile deviation on propeller noise. Physics of Fluids, 2023, 35: 027104. (Editor’s Pick)
查看原文View publication ↗截面翼型几何对螺旋桨气动声学特性具有决定性影响，但制造公差、磨损和加工技术限制会引入细小偏差，从而导致测量不确定性。本文在消声风洞中对直径 217.2 mm 的基准螺旋桨及其若干变型进行系统研究，通过改变有限尾缘厚度调整截面翼型，并用高精度数控加工保证细微几何差异。测力结果表明，气动性能对这些微小变化不敏感。当轴向来流速度低于 5 m/s 时，纯音和宽带噪声仅受到轻微影响；相比之下，有限尾缘厚度可以带来超过 3 dB 的明显降噪。研究还利用基于小波的波束形成方法分析声源特征，证实降噪源于叶尖附近尾缘噪声减弱。该研究有助于量化螺旋桨噪声测量的不确定性，并表明调整尾缘厚度可能成为实际降噪手段。
The geometry of the sectional airfoil has a determinative impact on the aeroacoustic characteristics of propellers. However, there are always slight deviations in the practical profiles due to manufacturing tolerance, wear loss, and limitations of processing techniques, which can potentially introduce uncertainties to aeroacoustic measurements. To this end, a systematic investigation is conducted on a benchmark propeller with a diameter of 217.2 mm and several of its variants in an anechoic wind tunnel. The variants are redesigned by modifying the sectional airfoil shapes with varying finite trailing-edge thicknesses. High-accuracy computer numerical control machining is employed to ensure the subtle geometrical differences between the blades. Force measurements indicate that the aerodynamic performances are insensitive to the slight variations of the sectional geometry, as expected. As for the acoustic performance, both the tonal and broadband noise are slightly affected when the axial flow speed is lower than 5 m/s. By contrast, a discernible noise reduction above 3 dB can be achieved due to the finite trailing-edge thickness. The noise source features are also investigated using a wavelet-based beamforming method, confirming that the noise reduction is caused by the weakened trailing-edge noise around the tip. This study is beneficial for the quantification of uncertainties in propeller noise measurements. It also suggests that adjusting trailing-edge thickness might be an useful approach in reducing propeller noise in practical applications.
- 2022Zhou T, Jiang H*, Huang B. Quad-copter noise measurements under realistic flight conditions. Aerospace Science and Technology, 2022, 124: 107542. ↗
真实飞行条件下的四旋翼噪声测量Zhou T, Jiang H*, Huang B. Quad-copter noise measurements under realistic flight conditions. Aerospace Science and Technology, 2022, 124: 107542.
Zhou T, Jiang H*, Huang B. Quad-copter noise measurements under realistic flight conditions. Aerospace Science and Technology, 2022, 124: 107542.
查看原文View publication ↗本文通过实验研究无人机在悬停、自旋、爬升、垂直飞行及巡航等代表性工况下的噪声特征。不同于可能受阵风、地面反射等不确定因素影响的室外实验，本研究在大型消声室内测量。采用覆盖 5.6 m×6.4 m 区域的地面矩形传声器阵列，以及侧墙上长 4.6 m 的线阵测量噪声及辐射指向性，并通过双目视觉系统实时追踪无人机运动。结果表明，飞行噪声对飞行高度、与观察者的相对距离和运动状态敏感。悬停时的噪声指向性与孤立螺旋桨相似，机身下方存在低噪声区域；巡航时，由于机身俯仰角，较高噪声区域出现在无人机后方。同步噪声与位置测量系统能够识别飞行试验中运动状态变化对应的声学响应。通过对噪声和运动追踪数据进行短时傅里叶分析，发现实时噪声谱图变化与螺旋桨转速变化之间存在相干关系。研究扩展了作者此前的工作，加深了对不同运行条件下无人机噪声特征的理解。
This work experimentally studies the noise features of flying drones under representative working conditions, including hover, spin, climb, vertical flight, and cruise. Being different from outdoor experiments where many uncertain factors, such as gust wind and ground reflections, could affect test results, measurements in this study were conducted in a large anechoic chamber. The noise was measured with a ground-based rectangular microphone array covering an area of 5.6 m×6.4 m and a 4.6 m linear array on the sidewall to account for emission directivity. A binocular vision tracking system was used to trace drones' motion in real-time. Results show that a flying drone's noise feature is sensitive to its flight altitude, relative distance from observers, and motion status. Interestingly, under hovering conditions, the noise directivity is similar to that of an isolated propeller, and a low-noise region is found underneath the fuselage. While for cruising flight, the region with higher noise levels is observed behind the drone due to the fuselage's pitch angle. More importantly, the synchronized systems for noise and position measurements allow finding of an acoustic response to any change in motion status across flight tests. A coherence between real-time changes in the noise spectrogram and variations of the propeller rotating speed is found, thanks to the short-time Fourier analysis of both noise and motion-tracking data. The present finding extends the authors' previous work, enabling a deeper understanding of general drone noise features under different operating conditions.
OPEN-SOURCE SOFTWARE
让研究方法，成为可用的工具。Research methods, ready to use.
分享实验室开发的开源计算软件，提供源码、使用文档与相关研究入口。Explore the laboratory’s open-source solvers, with source code, documentation and links to related research.
“