We propose a segregated Finite Volume (FV) - Spectral Element Method (SEM) for modelling aeroacoustic phenomena based on the Lighthill's acoustic analogy. First the fluid solution is computed employing a FV method. Then, the sound source term is projected onto the acoustic grid and the inhomogeneous Lighthill's wave equation is solved employing the SEM. The novel projection method computes offline the intersections between the acoustic and the fluid grids in order to preserve the accuracy. The proposed intersection algorithm is shown to be robust, scalable and able to efficiently compute the geometric intersection of arbitrary polyhedral elements. We then analyse the properties of the projection error and we numerically assess the obtained theoretical estimates. Finally, we address two relevant aeroacoustic benchmarks, namely the corotating vortex pair and the noise induced by a laminar flow around a squared cylinder, to demonstrate in practice the effectiveness of the proposed approach. The flow computations are performed with OpenFOAM , an open-source finite volume library, while the inhomogeneous Lighthill's wave equation is solved with SPEED, an open-source spectral element library.

翻译：我们提出了一种基于Lighthill声学类比的分离有限体积-谱元法，用于模拟气动声学现象。首先，采用有限体积法计算流体解。然后，将声源项投影至声学网格，并采用谱元法求解非齐次Lighthill波动方程。该新型投影方法通过离线计算声学网格与流体网格的交集来保证精度。所提出的交集算法具有鲁棒性、可扩展性，并能高效计算任意多面体单元的几何交集。随后，我们分析了投影误差的特性，并通过数值方法验证了理论估计结果。最后，我们针对两个经典气动声学基准问题——共旋涡对以及层流绕方柱诱导噪声——进行实际验证，以证明所提方法的有效性。流体计算采用开源有限体积库OpenFOAM执行，而非齐次Lighthill波动方程则通过开源谱元库SPEED求解。