Department of Physics, Technical University of Denmark, DTU Physics Building 309, DK-2800 Kongens Lyngby, Denmark.
Phys Rev E. 2023 Jan;107(1-2):015106. doi: 10.1103/PhysRevE.107.015106.
A theoretical model of thermal boundary layers and acoustic heating in microscale acoustofluidic devices is presented. Based on it, an iterative numerical model is developed that enables numerical simulation of nonlinear thermoviscous effects due to acoustic heating and thermal advection. Effective boundary conditions are derived and used to enable simulations in three dimensions. The theory shows how friction in the viscous boundary layers causes local heating of the acoustofluidic device. The resulting temperature field spawns thermoacoustic bulk streaming that dominates the traditional boundary-driven Rayleigh streaming at relatively high acoustic energy densities. The model enables simulations of microscale acoustofluidics with high acoustic energy densities and streaming velocities in a range beyond the reach of perturbation theory, and is relevant for design and fabrication of high-throughput acoustofluidic devices.
提出了一种微尺度声流设备中热边界层和声加热的理论模型。在此基础上，开发了一种迭代数值模型，能够对声加热和热对流引起的非线性热粘性效应进行数值模拟。推导并采用了有效的边界条件，以实现三维模拟。该理论表明，粘性边界层中的摩擦如何导致声流设备的局部加热。由此产生的温度场会产生热声体流，这在相对较高的声能密度下主导传统的边界驱动瑞利流。该模型能够模拟具有高声能密度和流速的微尺度声流，其流速范围超出了微扰理论的范围，与高通量声流设备的设计和制造相关。
