This experimental investigation concerns the effect of imposed axial acoustic velocity fluctuations on the primary atomization of a hollow cone liquid sheet in the presence of a strong air swirl. The atomization dynamics are elucidated by positioning the spray at an acoustic velocity node, antinode, and a mixed point in the standing wave field generated due to the imposed axial acoustic excitation. High-speed shadowgraph images acquired in-sync with dynamic pressure measurements are processed to clarify the unstable behavior observed in the spray dynamics; this was achieved by extracting key parameters such as breakup length, spatial growth rates, phase differences, and by employing Proper Orthogonal Decomposition (POD). A novel method to obtain the breakup length of a hollow cone spray from the position of maximum wave amplitude is presented. The breakup length is the smallest for the mixed point. The phase difference between the left and right half-angle fluctuations shows that the flapping motion of the spray is predominantly observed at the mixed point for different air-to-liquid ratios. Another novel approach is adopted to identify the physical mechanisms corresponding to each POD spatial mode by comparing POD spatial modes obtained from experiments to those generated artificially.

中文翻译：

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旋流场中空心锥液层的轴向声速相互作用

该实验研究涉及在存在强空气涡流的情况下施加的轴向声速波动对中空锥形液层初级雾化的影响。通过将喷雾定位在声速节点、波腹和由于施加的轴向声激励而产生的驻波场中的混合点，阐明了雾化动力学。处理与动态压力测量同步获取的高速阴影图像，以阐明在喷雾动力学中观察到的不稳定行为；这是通过提取分裂长度、空间增长率、相差等关键参数并采用本征正交分解 (POD) 来实现的。提出了一种从最大波幅位置获取空心锥形喷雾破碎长度的新方法。混合点的分裂长度最小。左右半角波动之间的相位差表明，对于不同的气液比，喷雾的扑动运动主要在混合点观察到。通过比较从实验中获得的 POD 空间模式与人工生成的 POD 空间模式，采用另一种新颖的方法来识别与每个 POD 空间模式对应的物理机制。