Numerical prediction of size, mass, temperature and trajectory of cylindrical wind-driven firebrands

作者：Oliveira Luis A^*; Lopes Antonio G; Baliga Bantwal R; Almeida Miguel; Viegas Domingos X

来源：International Journal of Wildland Fire, 2014, 23(5): 698-708.

DOI：10.1071/WF13080

• horizontal distance travelled
• mathematical models
• oscillations
• rotations
• spot fires
• total falling time
• trajectories

Mathematical models and numerical solution procedures for predicting the trajectory, oscillation, possible rotation, and mass and size time-evolution of cylindrical wind-driven firebrands are described and discussed. Two test problems and the results, used for validating the mathematical models, are presented. In one, experimental measurements of non-burning cylindrical particles falling in still air are compared to numerical predictions and in the other, predictions of time-evolution of mass and size of stationary burning particles in air flows are compared with experimental results reported in the literature. Results yielded by the proposed models for a demonstration problem involving cylindrical wind-driven firebrands, with the same initial volume, mass and position, but different initial aspect ratios and distinct initial orientations relative to the wind velocity, are then presented. These results show the following: the horizontal distance travelled by the firebrand from release to landing locations is an increasing function of its initial aspect ratio; and the initial orientation of the firebrand, and its subsequent oscillations including possible rotation, have a significant influence on its trajectory, thus it is important to account for them in mathematical models formulated for predicting the spread of fires by spotting.

• 出版日期2014