Forming the Convective Flows and a Cluster of Particles under Spot Heating

ABSTRACT

The behavior of self-organization of convective flows in a thin layer of liquid under point (local) heating is investigated experimentally. The interaction of thermocapillary and thermogravitational-free convection can lead both to self-organization of a cluster of micro-vortices in the form of hexagonal structures and to its partial disintegration. Correlation analysis of the velocity field shows that the characteristic convection scales change continuously over time. The largest size of the vortex flow corresponds to the layer diameter (20 mm); the integral convection scale (2.5 mm) characterizes the established interaction of vortex structures in a wide range of sizes; and the dimensions of hexagonal convective cells (80–100 µm) show the lower limit of the characteristic scale of vortex structures. The observed flow macrostructure is determined by the complex nonlinear interaction of vortices of the specified scales. The resulting value of the average integral convection scale can be effectively used to predict the convection velocity.

KEYWORDS:

• Benard–Marangoni convection
• self-assembly
• micro-particles
• liquid interface
• laser heating

Acknowledgments

The investigation with the laser technology was supported by the Tomsk Polytechnic University Competitiveness Enhancement Program.

The studies of heat and mass transfer were carried out within the framework of the state assignment with the IT SB RAS.

Declaration of interest statement

The authors declared that they had no interest conflict.