In this paper, a hybrid computational aero/hydro-acoustic approach is proposed to deal with acoustic scattering and flow-induced noise problems based on the sharp interface immersed boundary method (IBM). For the flow field, the incompressible Navier–Stokes equations are solved by an in-house direct numerical simulation solver. The acoustic field is predicted by solving acoustic perturbation equations (APEs). Both flow and acoustic solid boundaries with complexity and mobility are dealt with by the sharp interface IBM. Benchmark acoustic problems with varied scatterers in two and three dimensions are presented to validate the accuracy of the acoustic codes and boundary treatments. Then, the feasibility and accuracy of the present hybrid approach are validated by considering the problem of flow past a circular cylinder at a Reynolds number of 200. Subsequently, the present method is used to predict the noise generated by flow around a four-cylinder array in two-dimensions with two arrangements (i.e., square array and diamond array), and the flow and acoustic physics are investigated in detail. The results show that the square array retains a monopole-like sound-radiation shape, while the directivity pattern of the diamond array produces a dipole-like shape. In both the square and diamond arrays, the propagation of acoustic waves is affected by the Doppler effect, and the latter array results in a larger alternation of the propagation angle compared with the single cylinder due to the influence of the geometric configuration. The intensity of the radiated acoustic pressure is much greater for the diamond array compared to the square one in most circumferential directions, and the acoustic intensity of both arrays is greater than that of the single cylinder. The spectrums of the far-field acoustic pressure indicate that the two arrays and the single cylinder have similar peak frequencies and profiles, with vortex shedding playing the predominant role in noise generation in all three configurations.

在本文中，基于锐界面浸入边界法（IBM），提出了一种混合计算的气动/水力声学方法来处理声学散射和流动引起的噪声问题。对于流场，不可压缩的 Navier-Stokes 方程由内部直接数值模拟求解器求解。声场是通过求解声扰动方程 (APE) 来预测的。具有复杂性和移动性的流动和声学实体边界均由清晰的 IBM 界面处理。提出了具有二维和三维不同散射体的基准声学问题，以验证声学代码和边界处理的准确性。然后，通过考虑雷诺数为 200 时流过圆柱体的问题，验证了本混合方法的可行性和准确性。随后，利用本方法预测二维四柱体阵列（即方形阵列和菱形阵列）周围流动产生的噪声，并对流动和声学物理进行了详细研究。结果表明，方形阵列保留了类似单极子的声辐射形状，而菱形阵列的指向性图案产生了类似偶极子的形状。无论是方形阵列还是菱形阵列，声波的传播都受到多普勒效应的影响，而后者阵列由于几何构型的影响，导致传播角度的变化比单圆柱大。与方形阵列相比，菱形阵列在大多数圆周方向上的辐射声压强度要大得多，并且两个阵列的声强都大于单个圆柱体的声强。远场声压谱表明，两个阵列和单个圆柱体具有相似的峰值频率和轮廓，在所有三种配置中，涡旋脱落在噪声生成中起主要作用。