Storm activity is one of the factors in forest fire occurrence in various regions. Such fires are characterized by large areas of burned forests with a relatively small proportion of fires caused by cloud-to-ground lightning in their total number. In the summer of 2016, we conducted field observations of the thunderstorm activity in the territory of the Timiryazevskiy forestry in the Tomsk region using the global World Wide Lightning Location Network data. Thermophysical model of heating a coniferous tree wood trunk due to the electrical current of a cloud-to-ground lightning discharge is considered in the article. The problem is solved for a cylinder, which simulates a tree trunk. We consider a certain cross section of the trunk. The process of wood heating by a cloud-to-ground lightning discharge is described by the system of unsteady heat conduction differential equations with corresponding initial and boundary conditions. The stress-strain state of a tree trunk due to thermal stresses is simulated. A parametric study of the effect of discharge current-voltage characteristics on the temperature distribution in a tree trunk has been conducted. The current ranged from 15 to 35kA at a voltage of about 100kV. The voltage varied in the range from 50 to 120kV at a current of about 23.5kA. Thermal stress dependences on the radial coordinate have been obtained. The sizes of high temperature particles resulting from dispersing the surface layers of a coniferous tree have been determined.
- Cloud-to-ground lightning discharge
- Particle formation
- Thermal stress
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