A COMPUTER ALGORITHM FOR SIMULATING THE SPREAD OF WILDLAND FIRE PERIMETERS FOR HETEROGENEOUS FUEL AND METEOROLOGICAL CONDITIONS

This work describes a computer based technique for simulating the spread of wildland fire for heterogeneous fuel and meteorological conditions. The mathematical model is in the form of a pair of partial differential equations, and can model fuels whose fire perimeter for homogeneous conditions is any given shape, such as ellipses, double ellipses, lemniscates etc. Provided the fire does not attempt to burn into an already burnt out region, then the differential equations are easily solved and a simple method of solution is presented. To identify regions that are internal to the fire perimeter an algorithm that uses the turning number of a point in the plane relative to the fire perimeter is used. The algorithm is found to be reliable, and allows for the simulation of highly complex fire scenarios in a reasonable time. Example simulations are presented that involve variations in fuel, barriers, wind direction changes and multiple fires.