Experimental and numerical study of the Marangoni convection due to localized laser heating

Abstract

We study experimentally and theoretically convective flows, which are induced in a horizontal liquid layer by a concentrated heat source: the split coherent beam of laser radiation. The layer surface is deformable. Depending on controlling factors, laboratory experiments demonstrate a variety of flow structures and surface configurations. The flow primarily has a single vortex pattern, but in a certain range of governing parameters, secondary nonstationary vortices are superimposed. Among the surface configurations there are the concave meniscus, the convex one, and the concavo-convex one. The numerical simulation is performed on a mathematical model, which involves nonlinear partial di¤erential equations for two-dimensional amplitude functions associated with distributions of temperature, vorticity, and surface deformation. In the long-wave approximation, the model describes the contribution of thermocapillary convection to the heat transfer as well as the degree of the interface deformation. The proposed model generalizes the existing one by taking into account the heating inhomogeneity.

Laser-Induced Thermocapillary Convective Flows: A New Approach for Noncontact Actuation at Microscale at the Fluid/Gas Interface

“…The problem of modeling the convective flow has already been tackled by different authors. Models for the Marangoni convective flow due to continuous laser heating were proposed in [23], [35], models for the thermocapillary convective flow due to continuous laser heating were proposed in [34], [36] and for pulsed laser heating in [37]. These models were used as a base to propose a suitable model for the current system.…”

Thermocapillary flows and interface deformations produced by localized laser heating in confined environment

“…Therefore, it appears that dimple formation does not represent a general rule when fluid confinement starts to play a role, as already supported by classical Marangoni experiments in thin cells [13]. This transition from concave to convex interface deformation has been studied recently [14] but the generalization to two-liquid systems still deserves to be investigated. This is the goal of the present work.…”

Dynamics and flow characterization of liquid fountains produced by light scattering

“…The most famous example is thermal Marangoni flow (called optocapillarity when induced by light) due to heat transfer to the interface when a liquid layer absorbs light at the used optical wavelength. It was widely studied experimentally, theoretically and numerically as it is easily induced by a local laser-heating [1][2][3][4]. With the development of microfluidic toolboxes on the one hand, and the enhancement of the surface to volume coupling contributions with miniaturization, on the other hand, many efforts were concentrated towards the developments of optically induced surface-tensiondriven flows at the microscale.…”