Abstract Dynamic acoustic fields offer an interesting alternative for acoustic standing-wave fields in acoustic separation applications. This paper reports on an investigation of two methods for generating dynamic acoustic fields and their applicability for selective particle separation. The first method applies a dual-frequency excitation to generate a standing-wave field that in which the pressure nodes travel at constant velocity. The second method uses frequency-ramping, where the velocity of the nodes in the resulting standing-wave field depends on both time and position. Both methods were investigated analytically and with computational models, yielding a dimensionless number that predicts particle behavior without having to solve the differential equations of motion. This dimensionless number can also be used to estimate the acoustic pressure in practical applications. Experiments carried out with polyethylene particles and the two prototypes confirmed the theoretical and numerical predictions. Both methods are suitable for selective particle separation applications.

中文翻译：

---

厘米尺度尺寸选择性粒子分离的动态声场

摘要 动态声场为声分离应用中的声驻波场提供了一种有趣的替代方案。本文报告了对产生动态声场的两种方法及其在选择性粒子分离中的适用性的研究。第一种方法应用双频激励来生成驻波场，其中压力节点以恒定速度行进。第二种方法使用频率斜坡，其中产生的驻波场中节点的速度取决于时间和位置。这两种方法都经过分析和计算模型的研究，产生了一个无量纲数，可以预测粒子行为，而无需求解运动的微分方程。这个无量纲数也可用于估计实际应用中的声压。用聚乙烯颗粒和两个原型进行的实验证实了理论和数值预测。这两种方法都适用于选择性颗粒分离应用。