Departament de Física Aplicada, Universitat Politècnica de Catalunya-BarcelonaTech, c/E. Terradas 5, 08860 Castelldefels (Barcelona), Spain.
Ecole Supérieure de Physique et Chimie Industrielles (ParisTech), Laboratoire de Physique et Mécanique des Milieux Hétérogenes, Unités Mixtes de Recherche 7636 Centre National de la Recherche Scientifique, 10 Rue Vauquelin, 75231 Paris Cedex 05, France.
J Acoust Soc Am. 2014 Mar;135(3):1056-63. doi: 10.1121/1.4864483.
A method for the experimental measurement of inter-particle forces (secondary Bjerknes force) generated by the action of an acoustic field in a resonator micro-channel is presented. The acoustic radiation force created by an ultrasonic standing wave moves suspended particles towards the pressure nodes and the acoustic pressure induces particle volume oscillations. Once particles are in the levitation plane, transverse and secondary Bjerknes forces become important. Experiments were carried out in a resonator filled with a suspension composed of water and latex particles of different size (5-15 μm) at different concentrations. Ultrasound was generated by means of a 2.5 MHz nominal frequency transducer. For the first time the acoustic force generated by oscillating particles acting on other particles has been measured, and the critical interaction distance in various cases has been determined. Inter-particle forces on the order of 10(-14) N have been measured by using this method.
本文提出了一种在谐振器微通道中通过声场作用来测量颗粒间力（次级 Bjerknes 力）的实验方法。超声驻波产生的辐射力将悬浮颗粒推向压力节点，而声压则诱导颗粒体积振动。一旦颗粒处于悬浮平面，横向力和次级 Bjerknes 力就变得很重要。实验在充满悬浮液的谐振器中进行，悬浮液由不同尺寸（5-15μm）和不同浓度的水和乳胶颗粒组成。超声波由 2.5MHz 的标称频率换能器产生。本文首次测量了振动颗粒对其他颗粒产生的声力，并确定了在不同情况下的临界相互作用距离。通过这种方法测量到了量级为 10(-14)N 的颗粒间力。
