弹性空腔可压缩流动的剪切层不稳定性及振荡机理研究

高速空腔诱导的可压缩流动结构十分复杂，流场中经常形成高强度且多频率分量的动载荷激励，不仅加速了空腔薄壁结构的疲劳破坏，还可能引发结构共振，严重危及飞行器系统结构安全和作战效能提高。.本申请拟针对弹性空腔可压缩流动的剪切层不稳定性及振荡机理开展研究，以典型薄壁结构空腔为研究对象，通过风洞流场显示、非定常流动/振动特性测量、频谱分析和不稳定性分析等多种研究手段，获取弹性空腔可压缩流动时均/动态特性以及腔体结构振动特性，分析流场中涡扰动增长特性和波系演化规律，揭示弹性边界对扰动反馈回路和剪切层Kelvin-Helmholtz不稳定性的影响机制，阐明弹性空腔非定常气动激励对腔体结构振动的作用规律，研究空腔可压缩流动与结构振动相互作用机理，为探索飞行器非定常流动/振动/噪声耦合机理等前沿基础问题和解决内埋武器系统振动与噪声控制等工程实际问题提供技术储备。

The compressible flow over a cavity produces complex flow phenomena, which always involve intense aerodynamic load with several resonant frequencies. The load in such kind of flow can bring about structural damage to an aircraft, and its combat effectiveness may be severely affected. Characteristics of the compressible flow and structural vibration during interaction between a high-speed flow and elastic cavities with thin walls will be investigated through wind-tunnel experiments and theoretical analysis. Flow visualization, measurements of pressure fluctuation and vibration, analysis on spectrum and instability are conducted to obtain time-average and dynamic features of the interaction. Results provide access to study on instability of vortical perturbations and evolution of wave patterns, which can be used to reveal elastic boundaries’ effects on the feedback of vortical perturbations and the Kelvin-Helmholtz instability in a cavity flow. Based on similarity principal of aerodynamics and vibrations, we will investigate the interaction between elastic cavity walls and aerodynamic load. The present work is expected to shed light on coupling of unsteady flow, vibration and noise in a high-speed aircraft, as well as structural design and oscillations control of internal weapon bays.