Published works

The relative humidity of air is directly related to fuel moisture. Fuel moisture is often considered as the index of flammability in the context of bushfires. Variation of relative humidity and fuel moisture is considered to have a significant effect on the rate of spread of grassfire propagation and fire intensity. In this study, two sets of grassfire simulations have been conducted: one set with 0.21m grass and another set with 0.175m grass. For both sets the ambient temperature was kept constant while the relative humidity and fuel moisture were varied, with fuel moisture deduced from the McArthur MKIII-V GFDI model. A lower relative humidity was observed to lead to higher fire intensity and a faster rate of spread, which are intuitively expected. Froude number analysis showed that relative humidity can lead to change in the fire propagation mode (wind driven vs buoyancy driven), but the greater factor appears to be grass height (fuel load).