Effect of a Model Fire on Atmospheric Turbulence Characteristics

This paper presents the analysis and generalization of the results of studies of turbulence in flame and in the vicinity of a combustion source during model steppe and crown fires performed at the Basic Experimental Complex of Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, in the period from 2019 to 2022. The spectra of air temperature changes and the scales of induced atmospheric turbulence in the vicinity of the front of a model fire are obtained. The ranges of air temperature pulsation frequency corresponding to the inertial and dissipative sections of the energy spectrum are found for a steppe fire; dissipative processes start running at an altitude of 10 m at wavenumbers with log k > 1.58 and the corresponding pulsation frequency f > 3 Hz; no dissipative processes are observed at an altitude of 3 m. During a model crown fire, turbulent processes in the atmosphere correspond to the inertial part of the energy spectrum at an altitude of 10 m; dissipative processes hardly manifest themselves.