What flame spread model moves in the same direction as the airflow?

The concurrent flame spread model is characterized by the flames propagating in the same direction as the airflow. This model is often observed in scenarios where the fire is moving along a surface and the wind or airflow assists in spreading the flames. This alignment with the airflow enhances the intensity of the fire, as the flames are not only advancing due to the combustible material but are also receiving additional oxygen and fuel from the wind, facilitating a rapid combustion process.

In contrast, the counterflow model involves flames moving against the direction of airflow, which can result in reduced flame intensity and altered combustion dynamics. The reversed flow typically relates to situations where the air is being pushed toward the source of the fire, creating a different combustion environment. Static flow, on the other hand, denotes a lack of airflow, meaning that the flames would not benefit from any directionality related to wind, making it distinct from those models where movement and airflow play a critical role.