Analysis on Physical Mechanism of Sound Generation inside Cavities Based on Acoustic Analogy Method

• 作者: Dangguo Yang Jianqiang Li Jun Liu Yaohua Li Yi Zhang
• 来源期刊: 流体动力学(英文)
• 学科: 医学
• 关键词: CAVITY Physical Mechanism SOUND Generation Aerodynamic Noise SOUND PRESSURE Level SOUND PRESSURE Frequency SPECTRUM
• 年，卷（期）: ltdlxyw_2013,（1）
• 页码范围: 23-31
• 页数: 9页
• 分类号: R73

摘要

Analysis of coupling aerodynamics and acoustics are performed to investigate the self-sustained oscillation and aerodynamic noise in two-dimensional flow past a cavity with length to depth ratio of 2 at subsonic speeds. The large eddy simulation (LES) equations and integral formulation of Ffowcs-Williams and Hawings (FW-H) are solved for the cavity with same conditions as experiments. The obtained density-field agrees well with Krishnamurty’s experimental schlieren photograph, which simulates flow-field distributions and the direction of sound wave radiation. The simulated self-sustained oscillation modes inside the cavity agree with Rossiter’s and Heller’s predicated results, which indicate frequency characteristics are obtained. Moreover, the results indicate that the feedback mechanism that new shedding-vortexes induced by propagation of sound wave created by the impingement of the shedding-vortexes in the shear-layer and rear cavity face leads to self-sustained oscillation and high noise inside the cavity. The peak acoustic pressure occurs in the first oscillation mode and the most of sound energy focuses on the low-frequency region.