Fast microscale acoustic streaming driven by a temperature-gradient-induced non-dissipative acoustic body force

TL;DR

This paper demonstrates that non-dissipative acoustic body forces induced by temperature gradients can generate significantly stronger microscale acoustic streaming than traditional boundary-driven methods, enabling improved flow control and heat transfer.

Contribution

It introduces a novel thermoacoustic streaming mechanism driven by light-induced temperature gradients, surpassing traditional boundary-driven streaming in magnitude and controllability.

Findings

Thermoacoustic streaming velocity is ~50 times higher than boundary-driven Rayleigh streaming.

Streaming velocity is ~90 times higher than Rayleigh-Benard convection at 10 K/mm gradient.

Alteration of Rayleigh streaming occurs at only 0.5 K/mm temperature gradient.

Abstract

We study acoustic streaming in liquids driven by a non-dissipative acoustic body force created by light-induced temperature gradients. This thermoacoustic streaming produces a velocity amplitude approximately 50 times higher than boundary-driven Rayleigh streaming and 90 times higher than Rayleigh-Benard convection at a temperature gradient of 10 K/mm in the channel. Further, Rayleigh streaming is altered by the acoustic body force at a temperature gradient of only 0.5 K/mm. The thermoacoustic streaming allows for modular flow control and enhanced heat transfer at the microscale. Our study provides the groundwork for studying microscale acoustic streaming coupled with temperature fields.