Yang Zhang aims to gain new physical insights into the complex phenomena of firebrand spot fires by developing and applying advanced imaging and processing techniques
The recent wildfires in Portugal, Spain, USA and even Manchester have once again demonstrated the devastation a wildfire can make to life and property. How to control the spread of the wildfire and prevent life losses should be on the top agenda.
Firebrands or embers ignite spot fires away from the main fire, which can be very dangerous for several reasons. Firstly, multiple simultaneous spot fires will increase the total area of the active fire very quickly and can even cause a rapid acceleration of fire behaviour – a ‘blow-up’. Secondly, many initially safe areas may suddenly be encircled or cut off by the rapidly propagating and coalescing spot fires. Thirdly, it diminishes the effectiveness of firefighting resources very quickly.
Just weeks before writing this article, thirty firefighters were killed in China by a ‘blow-up’ wildfire. Therefore, it is very important to understand the transportation mechanisms of the firebrands and fire dynamics, and develop the capability to identify the firebrands that have the highest potential to initiate spot fires. As a result, warnings to areas of danger can be given earlier. Mitigation measures for structures and for landscape fuel management can be designed to reduce ignition and sources of firebrands. Firebrands are known to routinely travel several kilometres in the horizontal direction with high winds, which is often difficult for the public to realise and, as a result, the potential danger might be overlooked in the event of a wildfire.
Further quantitative investigation is currently difficult because the aerodynamically critical factors such as the firebrand geometry and its orientation with respect to the wind are hard to measure and model. A good understanding of the aerodynamic properties of firebrands are essential because a firebrand is not merely dragged to a faraway place by wind, it is actually able to glide like a small ‘aircraft wing’. My planned work will tackle these issues directly with unique 3D stereoscopic particle tracking diagnostics. My primary aim is to use advanced imaging based diagnostics to gain physical insights into the complex phenomena of wildland fire dynamics and to communicate with non-scientific stakeholders and the public for better fire control, fire risk reduction and lifesaving.