Optika Atmosfery i Okeana Journal

Vol. 36, issue 07, article # 7

Agafontsev M. V., Gerasimova L. O., Reino V. V., Shesternin A. N. Investigation of convective turbulence characteristics over a heated surface by high-speed thermography. // Optika Atmosfery i Okeana. 2023. V. 36. No. 07. P. 584–590. DOI: 10.15372/AOO20230707 [in Russian].
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Abstract:

The results are presented of laboratory experiments to determine the characteristics of convective turbulence over a heated metal surface for various heights and temperatures by high-speed thermography. The study of convective turbulence characteristics was carried out using a high-speed infrared camera by shooting the temperature field of low-inertia paper targets suspended above the heated surface simultaneously over the entire vertical plane of the IR camera field of view. Based on fluctuations in the temperature field of the target surface, the heat transfer coefficient, the intensity level of the convective flow, the total flow, and the amount of heat generated during measurements at different heights above the surface are determined. The energy spectra of convective turbulence are plotted under various turbulent conditions. An analysis of the turbulence spectra showed the presence of an inertial interval with a slope close to the 8/3 power law for all considered heights above the heated surface, temperatures, and turbulence conditions. Characteristics of convective turbulence obtained can be used when testing various optical adaptive laser beam control systems, studying the propagation of vortex laser beams and combustion centers, which are also characterized by convective turbulence with a further transition to atmospheric turbulence induced by combustion energy.

Keywords:

turbulence, convection, temperature fluctuation, high-speed thermography, laboratory experiment, energy spectrum

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