振动弹性板从波turbulence到动力皱曲的转变

Intermittent dynamic bursting in vertically vibrated liquid drops

A previously unreported regime of type III intermittency is observed in a vertically vibrated milliliter-sized liquid drop submerged in a more viscous and less dense immiscible fluid layer supported by a hydrophobic solid plate. As the vibration amplitude is gradually increased, subharmonic Faraday waves are excited at the upper surface of the drop. We find a narrow window of vibration amplitudes slightly above the Faraday threshold, where the drop exhibits an irregular sequence of large amplitude bursting events alternating with intervals of low amplitude activity. The triggering physical mec…

A Kolmogorov spectrum for strongly vibrating plates

In fluid turbulence, energy is transferred from a scale to another by an energy cascade that depends only on the energy dissipation rate. It leads by dimensional arguments to the Kolmogorov 1941 (K41) spectrum. Remarkably the normal modes of vibrations in elastic plates manifests an energy cascade with the same K41 spectrum in the fully non-linear regime. Moreover, the elastic deformations present large "eddies" together with a myriad of small "crumpling eddies", such that folds, developable cones, and more complex stretching structures, in close analogy with spots, swirls, vortices and other …

Harmonic and subharmonic waves on the surface of a vibrated liquid drop

Liquid drops and vibrations are ubiquitous in both everyday life and technology, and their combination can often result in fascinating physical phenomena opening up intriguing opportunities for practical applications in biology, medicine, chemistry and photonics. Here we study, theoretically and experimentally, the response of pancake-shaped liquid drops supported by a solid plate that vertically vibrates at a single, low acoustic range frequency. When the vibration amplitudes are small, the primary response of the drop is harmonic at the frequency of the vibration. However, as the amplitude i…

弹性薄板中波turbulence的Fourier分析

Fourier analysis of wave turbulence in a thin elastic plate

利用高速傅里叶变换轮廓术测量了振动平板变形的时空动态特性。分析了空时傅立叶谱。它表现出与弱湍流理论的前提一致的行为。波的各向同性连续谱被激发，非线性色散关系稍微偏离线性色散关系。还测量了色散关系的谱宽。该系统的非线性较弱，符合理论预期。有限尺寸效应进行了讨论。尽管与理论的定性协议，观察到的起源可能是由于耗散，最终吸收的Kolmogorov-Zakharov级联的能量通量的定量不匹配。