AI 中文总结
研究两层流体密度界面处混合，通过随机驱动合成射流阵列产生随机湍流猝发进行实验，用记录密度场解析界面演化，发现界面速度与密度跃变关系及不同密度差下界面变化情况，为地球物理混合动力学提供新见解。
AI 中文摘要
理解密度界面处的混合对于预测分层环境流中的输运至关重要。实验室研究大多依赖稳定、空间均匀的强迫，而自然中的湍流是间歇性和非均匀的。在此，我们展示了关于由随机驱动的合成射流阵列（RASJA）产生的随机湍流猝发驱动的两层盐分层流体的实验。用光衰减技术记录密度场，以解析界面演化。我们测量到界面向上速度随密度跃变减小，这与先前振荡网格研究中的幂律一致。在大密度差时，混合过程中界面锐化，与小密度跃变情况相反。背景势能分析表明两种情况下均存在不可逆混合，能量变化相当。这些结果将经典实验室观测扩展到更各向同性的强迫，为地球物理环境中混合动力学提供新见解。
英文摘要
Understanding mixing at density interfaces is essential for predicting transport in stratified environmental flows. Laboratory studies have mostly relied on steady, spatially uniform forcing, whereas turbulence in nature is intermittent and heterogeneous. Here, we present experiments on a two-layer salt-stratified fluid forced by random turbulent bursts generated with a randomly actuated synthetic jet array (RASJA). Density fields are recorded with the light attenuation technique, allowing us to resolve the interface evolution. We measure that the upward velocity of the interface decreases with the density jump, in agreement with the power-law found in previous oscillating-grid studies. At large density differences, the interface sharpens during mixing, contrary to the smaller density jump case. Background potential energy analysis demonstrates irreversible mixing in both cases, with comparable energy changes. These results extend classical laboratory observations to a more isotropic forcing, offering new insights into the dynamics of mixing in geophysical settings.
Comments23 pages, 12 figures
