A time-domain analysis for aeroacoustics-structure interaction of flexible panel

A time domain numerical method is proposed to investigate flow effect to acoustics in a duct with flexible panel in the present paper. When a mean flow carrying a plane wave is passing over a flexible panel in a duct, complex aeroacoustics-structure interaction (ASI) will occur. The acoustic wave and flow will induce vibration of the panel. The vibration will then re-radiate wave back to the fluid. The flow, acoustics and flexible panel dynamics are affecting each other. A numerical model is developed to correctly solve such kind of ASI problem. The numerical model introduced in the paper involves three parts: aeroacoustic model, structural dynamic model and numerical coupling. The aeroacoustic model resolves flow dynamic and acoustics; and the structural dynamic model resolves the panel vibration. A numerical methodology is developed to make sure two models are strongly coupled together. The ASI model is verified with theoretical analysis. For a single frequency incident wave propagating in duct, we calculated transmission loss for different panel length. Actually, the flexible panel in duct can effectively reduce transmission of acoustic wave. The mechanism of transmission loss due to flexible panel will be discussed. However, the duct system behaves different when a mean flow is present. Cases with Mach number = 0.1, 0.5 and 0.8 are calculated. The transmission loss is found generally much smaller than cases without flow. The flow affects propagation of flexural wave on the panel and effect transmission loss change. This effect of flow will be discussed.