A large-eddy simulation is performed on a single nonrotating airfoil with tip gap in order to highlight the noise sources in the tip-leakage flow. The geometry is composed of a NACA 5510 airfoil (5% camber, 10% thickness) mounted between two flat plates, with a 10 mm tip gap between the airfoil and one of the plates. The Reynolds number based on the chord is 960,000 and the Mach number is 0.2. The aerodynamic results from the simulation show the formation of the tip-leakage vortex and the interaction of the turbulent structures that exit the gap with the external flow near the trailing edge. Then, a Ffowcs Williams and Hawkings analogy is used to compute the far-field noise levels and an acoustic decomposition is performed to highlight the main surface contributions to the tip-leakage noise. The numerical simulation shows very good agreement compared with experiments and allows identification of the main noise source in the tip gap. The main noise source results from the interaction of the turbulent structures created in the tip gap close to the pressure side corner with the suction side tip edge. The scraping of turbulent structures along the tip edge is shown to be an efficient noise mechanism.

对具有尖端间隙的单个非旋转翼型进行大涡模拟，以突出尖端泄漏流中的噪声源。几何结构由安装在两块平板之间的NACA 5510翼型（外倾度为5％，厚度为10％）组成，翼型和其中一块板之间的尖端间隙为10 mm。基于和弦的雷诺数为960,000，马赫数为0.2。模拟的空气动力学结果显示了尖端泄漏涡流的形成以及离开间隙的湍流结构与后缘附近的外部流动的相互作用。然后，使用Ffowcs Williams和Hawkings类比来计算远场噪声水平，并进行声学分解以突出显示主表面对尖端泄漏噪声的影响。与实验相比，数值模拟显示出非常好的一致性，并且可以识别尖端间隙中的主要噪声源。主要噪声源是由在靠近压力侧角的尖端间隙中产生的湍流结构与吸力侧尖端边缘的相互作用产生的。沿尖端边缘刮擦湍流结构被证明是一种有效的噪声机制。