@article {bnh-4976, title = {Improvements to wind field generation in physics-based models to reduce spin-up time and to account for terrain, heated earth surface}, year = {2018}, month = {10/2018}, institution = {Bushfire and Natural Hazards CRC}, abstract = {

Wind is one of the most important environmental variables that affects the wildland fire spread and intensity. Previously, fire analysts and managers have relied on local measurements and site-specific forecasts to determine winds influencing a fire. However, advances in computer hardware increased the availability of electronic topographical data, and advances in numerical methods for computing winds have led to the development of new tools capable of simulating wind flow. Several numerical models have been developed for fire prediction. The most widely used physics-based models come with a limitation of computational expenses, because of which these are not suitable for operational use. Our main intention of this study is to reduce this limitation of physics-based models so that fire forecasts can be made faster and easier. Modelling wind in physics-based models such as Fire Dynamics Simulator (FDS) has been shown to reproduce promising results, but at an inordinate cost. So, we will be using FDS as physics-based model to simulate fire. There are various methods available to generate wind field in FDS. The conventional methods of wind field generation are either an unperturbed inlet profile with a roughness-trip or the by embedding artificial turbulence at the inlet. The wind fields generated by these inlet conditions are compared with each other as well as to the wind field generated using a mean-forcing method for neutral atmospheric conditions. We have then used these inlet conditions to study the effects of fire spread in FDS. Currently, we are working on introducing a method in FDS known as penalization method, so that we can use real time wind data from other wind models, such as Windninja into FDS and perform fire simulations. Our hypothesis is that introduction of this method would reduce the simulation time of fire cases to some extent and moreover can include terrain effect in the wind profiles.

}, issn = {415}, author = {Khalid Moinuddin and Sesa Singha Roy and Duncan Sutherland and Nazmul Khan} }