Hybrid Aero-Acoustics Prediction Method Coupled with RANS/LES Model and LEE Equation

Coupling the turbulent velocity generation model and the linearized Euler equation, a hybrid method of aerodynamic noise prediction is established. The unsteady NS method based on the RANS/LES model is applied to the turbulent velocity generation model of the hybrid method, which provides a reliable source term for the acoustic propagation equation. Linear Euler Equation is selected for the propagation of the sound source. The low-dispersion, low-dissipation and high-order scheme is used in the spatial-temporal discretization, and the Perfect Match Layer boundary condition for the far-field boundary is selected. The high-order interpolation algorithm is adopted for the turbulent velocity information exchange between the flow field grid and the acoustic field grid. The aerodynamic noise prediction of the M219 cavity model was conducted by using the statistical sound source with sound propagation (SNGR) method and the RANS/LES+LEE method respectively. By comparing the distribution and magnitude of sound source, the sound pressure curve and sound pressure level frequency-spectrum curve of the monitoring points, it can be concluded that the RANS/LES+LEE method can accurately capture the peak value of the sound pressure level. Compared with the experimental results, it is shown that the RANS/LES+LEE method is more suitable for simulating the acoustic propagation problems caused by flow-induced oscillations in the cavity than the SNGR method.