Boundary layer coupling of solid particles in water in an ultrasonic field

TL;DR

This study investigates how ultrasonic fields influence the localized velocity, pressure, and thermal interactions between silica particles in water, revealing effects relevant to particle agglomeration and concentration.

Contribution

It provides a detailed analysis of the coupled effects of ultrasonic fields on solid particles in water, focusing on the interactions at the nanoscale in the long wavelength regime.

Findings

Localized velocity, pressure, and thermal fluctuations decay rapidly around particles

Coupled particle effects influence agglomeration in ultrasonic fields

Analysis conducted for 500 nm particles at 9.7 MHz frequency

Abstract

In an ultrasonic field the region around a solid particle experiences small, localised velocity, pressure, and thermal fluctuations that decay rapidly over short length scales. Herein, we investigate the overlap of the rapidly decaying fields between two silica particles in water in the case where the particles are aligned with each other in the direction of the applied field. We explore the velocity, pressure, temperature, and vorticity in the region of the particles. We discuss the coupled particle effects in ultrasonic waves as particles begin to agglomerate or become more concentrated. The analysis is conducted in the long wavelength regime for particles of diameter 500 nm and frequency 9.7 MHz.