FIRETEC and WFDS Modeling of Fire Behavior and Smoke in Support of FASMEE

Project Description

Creating a validation dataset for physics-based fire behavior models is a very demanding measurement task for fires that are significantly influenced by variation in vegetation and local winds.

The objective of FASMEE is to obtain measurements that can be used to evaluate and advance operational smoke models. In current operational models, the physical processes driving fire growth, fire behavior, and plume development are not explicitly modeled. However, these processes are explicitly modeled in physics-based fire behavior models that use the methods of computational fluid dynamics (CFD). Thus, these physics-based fire behavior models, if suitably validated, could be used to help advance operational smoke models.

We acknowledge support from the Joint Fire Science Program under Project #16-4-05-1.

Purpose and Scope

The objective of FASMEE is to obtain measurements that can be used to evaluate and advance operational smoke models. This project outlined the design of a field experiment for validation of physics-based wildland fire behavior models.

Methods

A validation dataset would require the characteristics and distribution of vegetation at spatial scales relevant to the behavior of the flank fire, which for these fires is approximately 1 meter. Validation of physics-based fire behavior models, however, requires a wide range of environmental and fire behavior information.

Implementation

The focus of this project shifted to determining what measurements would best support smoke plume model validation, especially from the point of view of what fire behavior measurements would be needed to inform smoke models of the heat source due to the fire. This led to the development of what is called the burner method and an effort to identify the field measurements required to support its implementation.

Key Findings

• Based on a number of factors (including the expected fire behavior, plot size, ping-pong ball ignition procedure, and the outcomes of past field experiments) the proposed FASMEE burns with low to moderate fire intensity are not suitable for a measurement effort whose goal is the creation of validation datasets for physics-based fire behavior models.
• It is possible to provide the necessary observations to run and test the next generation smoke models while not explicitly simulating fire behavior.
• It is critical that design and implementation of the field experiments be conducted within the supporting framework of geospatial science and technology practices. If this is not done, FASMEE is likely to result in a set of disjoint, nonintegrated, datasets that will hinder their wide use by the scientific community of interest.